Glass technology

Publications Glass and Glass Technology

2024

  • Gomes Fernandes, R., Selle, S., Wagner, T., Menzel, M., Deubener, J.
    Local fluctuation of the relative density of glass powders over the entire viscous sintering process
    Journal of Non-Crystalline Solids 625 (2024) 122746, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2023.122746.
    (https://www.sciencedirect.com/science/article/pii/S0022309323006117)

    Abstract
    Using high-resolution X-ray computed tomography and 3D image analysis, the global relative density was determined and fluctuations in relative density were localized and quantified in a series of sintered glass bodies made of 80 μm glass spheres over the entire sintering process. A representative volume element (RVE) in the sintered body was divided into cubic volumes of 500, 250 and 125 µm edge length by an automatic segmentation routine. It was found that the expected decrease in coarseness C from the initial to the final sintering stage is interrupted by an intermediate stage with highest C and a characteristic bimodal density distribution. The bimodality of the intermediate stage is due to spatially separated denser arrangements within the RVE with closed pores and less dense arrangements with a network of interconnected or open pores. The spatial heterogeneity is biased in the z-direction due to friction caused by adhesion with the substrate.
     
  • Zandona, A.,  G. Helsch, J. Deubener
    Nomenclature of functional crystals in glass-ceramics: A recommendation based on aluminosilicate solid solutions
    Journal of Non-Crystalline Solids 633 (2024) 122954, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2024.122954.
    (https://www.sciencedirect.com/science/article/pii/S0022309324001352)

    Abstract
    The need for a homogeneous nomenclature has become particularly acute due to the increasing digitization and open accessibility of research data provided by peer-reviewed scientific publishers and other online repositories and databases, and the resulting big-data mining approaches. Therefore, basic guidelines for a general nomenclature system based on the crystallographic structure are presented to enable scientists, engineers and technologists to name the crystalline phases detected in glass-ceramics as uniformly and unambiguously as possible and exemplified by quartz, keatite and indialite solid solutions. The adoption of a standardized nomenclature is essential to ensure effective use of the vast scientific knowledge available today in accordance with the FAIR (findable, accessible, interoperable, reusable) data management systems.
     
  • Ueberricke, L., T. Murata, H. Ikeda, S. Nakane, J. Deubener
    Crystal Growth in Oxide Melts – From CALPHAD Thermodynamic Modeling to Statistical Prediction
    Acta Materialia 273 (2024) 119960, ISSN 1359-6454,
    doi.org/10.1016/j.actamat.2024.119960.
    (https://www.sciencedirect.com/science/article/pii/S1359645424003124)

    Abstract
    Using a thermodynamic database approach (CALPHAD), thermodynamic parameters of crystal growth of 31 stoichiometric and non-stoichiometric glasses are calculated. Together with these parameters, the measured growth rates, taken from both literature and in-house measurements, are interpreted in the framework of four interface-controlled growth models: normal, screw-dislocation, 2D growth and a combination of the latter two. A multiple linear regression model is used to explain the maximum crystal growth rate and viscosity at the liquidus temperature with the above growth mechanisms. This finding seems to reflect a general trend and can therefore be used to avoid unintentional devitrification phenomena or to derive their temperature-time range based on the sole knowledge of glass viscosity and liquidus temperature. In future research, it can also help to reduce the experimental workload required for the development of novel glasses and glass-ceramics.
     
  • Zhang, X., Sibari, R., Chakraborty, S., Baz, S., Gresser, G.T., Benner, W., Brämer, T., Steuernagel, L., Ionescu, E., Deubener, J., Beuermann, S., Ziegmann, G. and Wilhelm, R.
    Epoxy-Based Carbon Fiber-Reinforced Plastics Recycling via Solvolysis with Non-Oxidizing Methanesulfonic Acid.
    Chemie Ingenieur Technik (2024)
    https://doi.org/10.1002/cite.202300243

    Abstract
    The urgent requirement for efficient recycling strategies in the wind energy industry prompted this study to explore the behavior of methanesulfonic acid (MSA) in the solvolysis of carbon fiber-reinforced plastics (CFRP), as an alternative to standard solvents and acids. For the investigation, two layers of carbon fibers, infused with amine-based epoxy through a vacuum-assisted resin infusion process, were applied. The results showed that MSA was the most effective solvent for the solvolysis of CFRP, compared to other investigated common acids. The recycled products demonstrated satisfactory properties for both the matrix and fiber, which were comparable to those of the virgin materials.
     
  • Alessio Zandonà, Beatriz Paiva Da Fonseca, Gundula Helsch, Vinzent Olszok, Michael J. Pitcher, Haytem Bazzaoui, Alfred P. Weber, Mathieu Allix, Joachim Deubener
    Structural features and thermal expansion of zinc aluminosilicate quartz solid solutions
    Journal of the European Ceramic Society (2024), ISSN 0955-2219
    doi.org/10.1016/j.jeurceramsoc.2024.05.046.
    (https://www.sciencedirect.com/science/article/pii/S0955221924004631)

    Abstract
    Zinc aluminosilicate (ZAS) glasses were synthesized along the peraluminous join (SiO2 contents between 95 and 50 mol%) by melt-quenching or sol-gel spray-drying and subjected to controlled heat treatments to obtain ZAS quartz solid solutions (Zn-Qz-ss). The precipitation of Zn-Qz-ss is non-stoichiometric with respect to their parent glass and the crystals undergo a compositional evolution during annealing, even in absence of secondary crystalline phases. Near-hexagonal high-quartz-like crystals with negative thermal expansion (down to −3 × 10−6 K−1) can be obtained in the range 50–80 mol% SiO2, while SiO2-richer crystals exhibit positive thermal expansion at room temperature (up to 29 × 10−6 K−1). Zn2+ ions occupy two distinct positions within the structural channels of quartz, with a strong preference for 4-fold coordination. In analogy to lithium aluminosilicate quartz solid solutions (Li-Qz-ss), the low-to-high phase transition exhibits a linear correlation to the composition of the crystals.
     
  • Alessio Zandonà, Victor Castaing, Alexander I. Shames, Gundula Helsch, Angela Pirri, Guido Toci, Joachim Deubener, Mathieu Allix, Adrian Goldstein
    Effect of the interaction between basicity and reductive character of melting atmosphere – both extreme – on the oxidation and coordination states assumed by transition metals when doped to silicate glasses
    Journal of Non-Crystalline Solids 637 (2024) 123038, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2024.123038.
    (https://www.sciencedirect.com/science/article/pii/S0022309324002175)

    Abstract
    The influence of an extremely reductive melting atmosphere on the oxidation and coordination states adopted by transition metals in an ultrabasic host was evaluated. An invert glass (46SiO2·11Na2O·21CaO·22BaO, basicity = 0.71) was synthesized in container-less conditions, on a jet of Ar−5%H2. Performed measurements included optical absorption, optical emission and electron paramagnetic resonance spectroscopy. The results revealed that the used atmosphere dramatically decreases the oxidation state(s) dopants assume, compared to those stable under oxidative melting in such a host. After reductive melting: (i) Ti3+ appears alongside Ti4+; (ii) V3+ is added to V5+; (iii) Mn2+ fully substitutes Mn3+ and Mn5+; (iv) Cu2+ is entirely replaced by Cu+and Cu0. These results could be rationalized considering the action of additional factors like ligand-field stabilization energy, ionization energy and special filling numbers of the 3d-subshell. They modulate the interaction between basicity and atmosphere redox character, in a way specific to each transition metal.
     
  • Bornhöft,H., J. Deubener
    Processes to ensure adherence and their kinetics at the interface between vitreous porcelain enamels and sheet steel
    Email – Mitteilungen des Deutschen Emailverbandes e.V. 72 (2024) 20-23

    Abstract
    To unravel the effect of minor steel components on enamel adherence, 22 sheet steals (different producers, 0.5-3 mm thick) were subjected to a standardized coating and firing protocol (one coat, one fire at 800-840 °C for 1-20 min) and a subsequent deep drawing test. Chemical composition of sheet steal was analysed using optical emission spectroscopy (Spark-OES), while line-scans across the enamel-steel interface were recorded using electron microscopy and energy dispersive X-ray spectroscopy (EDX). To collect chemical information from larger lateral sizes (up to 80 mm2), depth-profiles across the interface were carried out using secondary neutral-mass spectrometry (SNMS). Mechanical adherence of the enamel on the sheet steal was assessed from the formation of an interface layer, which is uncovered by the deep drawing test and can be scaled with an adherence index F between 0 and 100%. The kinetic analysis includes time-temperature-adherence index (T-T-F) representations, which emphasize that interface processes and concurrent adherence development (F up to 100%) are generally fast (1-2 min) in the considered temperature range. However, they also reveal that certain minor elements, such as phosphorous can cause a noticeably restriction in the growth of F and insufficient adherence layer formation.
     

  • Gogula, S., H. Bornhöft, L. Wondraczek, M. Sierka, A. Diegeler, R. Müller, J. Deubener
    Optical Real-Time Castability Evaluation for High-Throughput Glass Melting
    Glass Europe 2 (2024) 83-93
    doi.org/10.52825/glass-europe.v2i.1359

    Abstract
    A novel optical real-time method for evaluating the castability of glass forming melts for laboratory furnaces is presented. The method is based on the analysis of top view images of the melt surface inside the crucible during melting after being subjected to a small mechanical impulse. In this way, the melt surface is excited to oscillate. The difference in contrast between two images taken in quick succession scales with the viscosity, with a larger difference occurring at lower viscosities. The method is designed as an instrument for the in-line evaluation of the castability for a high-throughput glass melting system as part of the joint project “GlasDigital” in the framework of the German Platform Material Digital initiative but is applicable to other laboratory furnaces as well.
     

  • Selle, S., Bornhöft, H., Wendel, J. C., Deubener, J.
    Overview of the Precipitates in a Ground-Coat Vitreous Enamel Using Analytical TEM
    Glass Europe 2, 95–114
    doi.org/10.52825/glass-europe.v2i.1269

    Abstract
    Precipitates in the ground-coat vitreous enamel, which form when the dried coating is fired and cooled on sheet steel, are essential for the function of the enamelling. They lead to an interlocked metal-glass interface and are triggered by redox-driven processes in a glass layer saturated with iron. Using analytical transmission electron microscopy, it is shown that alloys of the Fe-Co-Ni-Cu system not only precipitate near the interface, where they contribute to adhesion through an interlocking interface, but also form nanocrystallites that are finely distributed in the enamelled glass to a depth determined by the diffusivity of Fe2+ (30 μm after four minutes of firing) and probably contribute to the toughening of this glass layer. The saturation with iron also prevents the segregation of the glass flux and opacifier calcium fluoride, which only occurs far from the interface in the chemically unmodified base glass. At the metal-glass interface, however, phosphorus traces diffuse from the steel and precipitates in the form of calcium phosphate needles that grow into the enamelled glass.

2023

  • Murata, T., S. Nakane, H. Yamazaki, R. Al-Mukadam, J. Deubener
    Heterogeneous crystal nucleation, viscosity and liquidus temperature in the system lithium metasilicate – lithium disilicate
    Journal of Non-Crystalline Solids 605 (2023) 122170, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2023.122170.
    (https://www.sciencedirect.com/science/article/pii/S002230932300039X)

    Abstract
    The heterogeneous crystal nucleation of five glasses along the compositional join between lithium disilicate and lithium metasilicate was studied by differential scanning calorimetry (DSC) and high-temperature optical microscopy (HTOM). In addition to DSC and HTOM, liquidus temperature and viscosity were measured. DSC and HTOM consisted of 147–378 repetitive cooling runs for each melt and method. DSC and HTOM showed that the crystal nucleation rate was highest for a glass of ∼63 mol% silica and that the first crystallite consisted of intergrown lithium metasilicate and quartz. In the case of DSC, primary crystallization of lithium disilicate was additionally observed, which was treated as an oxygen-related artifact. The viscosity at the maximum nucleation rate was almost constant for each melt, while the liquidus temperature resulting from the linear extrapolation of the DSC-endotherm for a heating rate of 0 K min−1 was 20–30 K higher than that calculated from thermodynamic properties.
     
  • Zandona, A.,  V. Castaing, A.I. Shames, G. Helsch, J. Deubener, A.I. Becerro, M. Allix, A. Goldstein
    Oxidation and coordination states assumed by transition metal dopants in an invert ultrabasic silicate glass
    Journal of Non-Crystalline Solids, 603 (2023) 122094, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2022.122094.
    (https://www.sciencedirect.com/science/article/pii/S0022309322006883)

    Abstract
    An ultrabasic invert silicate glass (46SiO2·11Na2O·21CaO·22BaO, optical basicity index equal to 0.71) was synthesized (O2 atmosphere) and used as host for various transition metal dopants. Optical absorption, emission and electron paramagnetic spectroscopies were used to characterize oxidation and coordination states. Some of the dopants displayed only their maximal oxidation state (Ti4+, V5+, Cr6+, Mo6+ and W6+). Others exhibited mixed valences: (i) Mn3+ was the dominant species, alongside Mn2+ and Mn5+; (ii) stable Fe3+ prevailed, although some Fe2+ was preliminarily suggested by the absorption spectrum; (iii) Co3+ probably accompanied the dominant Co2+ tetrahedral oxide complex; (iv) like in “conventional” silicate glasses, only Ni2+ was detected, though simultaneously located in tetrahedral and octahedral sites (somewhat distorted); (v) Cu+ was surprisingly identified alongside the expected 6-fold coordinated Cu2+. Drastic reduction of the oxygen content in the melting atmosphere led to conversion of Cr6+ to Cr3+, despite the extreme basicity of the host.
     

  • Fritzsche, J.O., B. Rüdinger, J. Deubener
    Slow coarsening of tetragonal zirconia nanocrystals in a phase-separated sodium borosilicate glass
    Journal of Non-Crystalline Solids 606 (2023) 122206, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2023.122206.
    (https://www.sciencedirect.com/science/article/pii/S0022309323000753)

    Abstract
    A Zr4+-containing sodium borosilicate glass (ZNBS) and a zirconium-free reference glass (NBS) were prepared by melt quenching. Thermal analysis revealed two glass transitions, indicating that both glasses exhibit phase separation into boron- and silica-rich domain structures already after quenching to room temperature. Electron micrographs showed that annealing of NBS and ZNBS glasses initiated the coarsening of these domains and the precipitation of metastable t-ZrO2 in the boron-rich matrix of the ZNBS glass. The coarsening kinetics of the silica-rich domains followed the theoretical predictions (power law exponent = 1/3), while the coarsening of the t-ZrO2 crystallites was much slower. The time evolution of the average size of t-ZrO2 nanocrystallites from small angle X-ray scattering (SAXS) and high-temperature X-ray diffraction (HTXRD) experiments revealed a coarsening exponent of ∼1/6. This slow coarsening of t-ZrO2 is assumed to be confined by the domain structure of the primary phase separation.
     

  • Di Genova, D., D. Bondar,  A. Zandonà, P. Valdivia, R. Al-Mukadam, H. Fei, A.C. Withers, T. Boffa Ballaran, A. Kurnosov, C. McCammon, J. Deubener, T. Katsura
    Viscosity of anhydrous and hydrous peridotite melts
    Chemical Geology 625 (2023) 121440, ISSN 0009-2541
    doi.org/10.1016/j.chemgeo.2023.121440.
    (https://www.sciencedirect.com/science/article/pii/S0009254123001407)

    Abstract
    The melt viscosity (η) of anhydrous and hydrous peridotite was investigated using a multipronged approach combining micropenetration viscometry, conventional DSC, flash DSC and Brillouin spectroscopy. Raman spectroscopy measurements were used to verify the absence of crystallization and/or degassing during high-temperature measurements of these extremely reactive glasses and melts, ensuring that the data corresponded to the crystal-free melt viscosity. Based on the experimental data, an accurate description of the viscosity of peridotite melts over thirteen orders of magnitude (from Tg to η ≈ 10−1 Pa s) is provided in a broad range of compositions and oxidation states. Since empirical models predict viscosities that can significantly deviate from measured data to varying degrees, a new model was developed for the temperature- and H2O-dependent viscosity of peridotite melts (up to 12 mol% H2O content).

  • Zandonà, A., E. Véron, G. Helsch, A. Canizarès, J. Deubener, M. Allix, C. Genevois
    Crystallization Mechanism of Gel-Derived SiO2–TiO2 Amorphous Nanobeads Elucidated by High-Temperature In Situ Experiments
    Crystal Growth & Design (2023)
    doi.org/10.1021/acs.cgd.3c00300

    Abstract
    SiO2–TiO2 amorphous nanobeads with a TiO2 content up to 50 mol % were synthesized by sol–gel spray drying. Their crystallization during heat treatments was then characterized by in situ high-temperature techniques including X-ray diffraction, Raman spectroscopy, and particularly high-resolution transmission electron microscopy. Intrinsic nanoscale chemical modulations could be identified already in the as-prepared nanobeads and were shown to play a major role for the nonisochemical precipitation of TiO2 nanocrystals during heating experiments: the size and compositional contrast of such fluctuations progressively evolved and increased until the emergence of long-range ordering. The formation of TiO2 polymorphs occurred according to Ostwald’s rule of stages, with the metastable TiO2(B) phase acting as a precursor to stabilize anatase and rutile. The temporary appearance of TiO2(B) nanocrystals at early annealing stages was interpreted as the first direct experimental observation of subcritical crystalline nuclei.

  • Hampel, S., F. Sand, D.A. Murcia Gonzalez, G. Pepponi, G. Helsch, J. Deubener, T. Schirmer, A. Fittschen, U.E.A. Fittschen
    Chelate complexed multi-elemental printing performance of a small and cost efficient picoliter droplet printing device for micro preparation
    Spectrochimica Acta Part B: Atomic Spectroscopy, 206 (2023) 106716, ISSN 0584-8547
    doi.org/10.1016/j.sab.2023.106716.
    (https://www.sciencedirect.com/science/article/pii/S0584854723001039)

    Abstract
    We introduce an inexpensive modular picoliter pipetting device using modified commercially available thermal inkjet cartridges. The system is capable of reliable deposition of 65 elements. The printing solutions were modified to prevent the dissolution of Ni from the nozzle head, keeping those at a pH of >9. Loss of cations to the glass surfaces inside the nozzle head is prevented by forming anionic complexes with ethylenediaminetetraacetic acid in basic conditions. For some elements, e.g., Si, additives like tetramethylammonium hydroxide are necessary.
    The volumes of the droplets were obtained, weighing 30,000–360,000 droplets ejected by the printer using a laboratory scale. The droplet volume was within a range of 142–184 pL, depending on the formulation. The delivered elemental masses and the reproducibility were determined using total reflection X-ray fluorescence analysis and inductively coupled plasma optical emission spectrometry. Delivered masses were in the range of 0.98 pg – 11.9 pg per element and droplet.
    The shape of deposits of about 31 pg per element was studied using atomic force microscopy, optical microscopy, and confocal laser scanning microscopy. They were mostly spherical and ca. 14 μm in diameter and ca. 2 μm in height. The broad range of printable elements allows for the micro preparation of solid compounds for establishing a grazing incidence X-ray diffraction analysis library. As an example, the MgAl2O4 spinel was synthesized by printing of the formulation and subsequent calcination. Here we show its performance for the preparation of minerals in the context of recycling of critical elements from pyrometallurgical slags.

  • Deubener, J., H. Behrens, R. Müller
    An overview on the effect of dissolved water on the viscosity of soda lime silicate melts
    Journal of Non-Crystalline Solids X, 19 (2023) 100195, ISSN 2590-1591
    doi.org/10.1016/j.nocx.2023.100195.
    (https://www.sciencedirect.com/science/article/pii/S259015912300047X)

    Abstract
    In this review article, the impact of dissolved water on the viscous properties of soda lime silicate melts is addressed against the background of the upcoming switch from natural gas to hydrogen combustion. This change will lead to an increase in the total water content of the glasses by up to 0.4 mol%. In order to better define possible influences of water speciation, water-rich glasses were synthesised under increasing pressure up to the kbar range. It is shown that a distinction must be made between the influence of dissolved OH-groups and H2O-molecules in order to accurately reflect the dependence of isokom temperatures on water content. In addition, an increase of one order of magnitude in the tolerance to higher deformation rates was observed for the range of expected increased water contents during isothermal deformation processes, which is based on the time-temperature superposition principle, i.e. congruent flow curves were determined under isokomal conditions.
     

  • Fielitz, P., G. Helsch, G. Borchardt, J. Deubener
    Al-26 and O-18 tracer diffusion in a titania-coated sodium aluminosilicate glass
    Journal of Non-Crystalline Solids 614 (2023) 122400, ISSN 00223093
    doi.org/10.1016/j.jnoncrysol.2023.122400.
    (https://www.sciencedirect.com/science/article/pii/S0022309323002661)

    Abstract
    Although TiO2 is a common nucleating agent in the production of aluminosilicate glass-ceramics, its role as a catalyst for the nucleation of the functional crystal remains unclear. Therefore, the Ti, Al and O mobility was studied in situ using 26Al and 18O tracer diffusion and Ti chemical diffusion experiments in an aluminosilicate melt of albite composition. The albite glass serves as a surrogate for lithium and magnesium aluminosilicate glass-ceramic compositions, as it allows to study atomic mobilities free of crystallisation artefacts. The depth profiles showed that Al mobility increased significantly and became comparable to that of oxygen when Ti simultaneously diffused into the glass. In the absence of Ti, the diffusivity of Al was two orders of magnitude lower than that of oxygen. The co-diffusion coefficients of Ti and Al seem to confirm a proposed preferential structural linkage between Al and Ti species in the network structure of aluminosilicate melts.
     

  • Reinsch, S., T. Welter, R. Müller, J. Deubener
    Hydrogen Permeability of Tectosilicate Glasses for Tank Barrier Liners
    Glass Europe 1 (2023) 1–11.
    doi.org/10.52825/glass-europe.v1i.425

    Abstract
    The permeation of hydrogen gas was studied in meta-aluminous (tectosilicate) glass powders of Li2O×Al2O3×SiO2 (LAS), Na2O×Al2O3×SiO2 (NAS) and MgO×Al2O3×SiO2 (MAS) systems by pressure loading and vacuum extraction in the temperatures range 210–310 °C. With this method, both the solubility S and the diffusivity D were determined, while the permeability was given by the product SD. For all glasses, S was found to decrease with temperature, while D increased. Since the activation energy of diffusion of H2 molecules exceeded that of dissolution, permeation increased slightly with temperature. When extrapolated to standard conditions (25 °C), the permeability of tectosilicate glasses was found to be only 10-22–10-24 mol H2 (m s Pa)-1, which is 8–10 magnitudes lower than most polymers. Thin glass liners of these compositions are expected to be the most effective barrier for tanks of pressurised hydrogen.
     

  • Fielitz, P., G. Helsch, J. Löschmann, R. Gustus, G. Borchardt, J. Deubener
    Oxygen-18 tracer diffusion in a crystallised lithium-aluminosilicate glass
    Journal of Non-Crystalline Solids 616 (2023) 122470, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2023.122470.
    (https://www.sciencedirect.com/science/article/pii/S0022309323003368)

    Abstract
    In this work we present first 18O tracer diffusion data in a crystallized LAS4 glass. The glass of LAS4 composition (close to Li2O⋅Al2O3⋅4SiO2) is free of nucleating agents and has a very low tendency to nucleate crystals in the volume. A thin ZrTiO4 layer (∼70 nm thick) was deposited by argon ion beam sputtering and served to preferentially nucleate high-quartz solid solution crystallites from the surface. All samples crystallised at the very early stage of the respective diffusion annealing time, i.e. virtually before the onset of the 18O tracer diffusion. The microstructure of the crystallised LAS glass is composed of crystalline domains (high-quartz solid solutions and keatite solid solutions) and a glassy phase of low viscosity in the domain boundaries. The oxygen transport occurs predominantly in the glassy phase of the domain boundaries and is faster than the transport of network forming cations or larger configurations in the glassy phase.
     

  • Processes to ensure adherence and their kinetics at the interface between vitreous porcelain enamels and sheet steel
    Hansjörg Bornhöft, Joachim Deubener
    International Enamellers Congress, Kyoto, Japan, May 8-11, 2023, 4 (E-04)
    ieiworlddotorg.wordpress.com/congress/
    ieiworlddotorg.files.wordpress.com/2023/10/final-international-enamellers-congress.pdf
     

  • Valdivia, P., A. Zandonà, A. Kurnosov, T.B. Ballaran, J. Deubener, D. Di Genova
    Are volcanic melts less viscous than we thought? The case of Stromboli basalt
    Contrib Mineral Petrol 178 (2023) 45
    doi.org/10.1007/s00410-023-02024-w

    Abstract
    Melt viscosity is one of the most critical physical properties controlling magma transport dynamics and eruptive style. Although viscosity measurements are widely used to study and model the flow behavior of magmas, recent research has revealed that nanocrystallization of Fe–Ti-oxides can compromise the reliability of viscosity data. This phenomenon can occur during laboratory measurements around the glass transition temperature (Tg) and lead to the depletion of iron and titanium in the residual melt phase, with a significant increase in viscosity. Accurate viscosity measurements play a crucial role in determining the reliability of empirical models for magma viscosity, which are used to evaluate eruptive scenarios in hazardous areas. Here, we quantify the reliability of empirical models by elaborating a new viscosity model of Stromboli basalt that relies exclusively on viscosity data obtained from nanocrystal-free samples. We show that empirical models so far used to estimate melt viscosity at eruptive conditions overestimate Stromboli viscosity by a factor ranging between 2 and 5. In the context of numerical modelling of magmatic processes at Stromboli volcano, we analyse and interpret this finding. Based on our findings, we draw the conclusion that Stromboli basalt is anticipated to ascend from the storage area to the vent at a faster rate than previously hypothesized.

  • Paiva Da Fonseca, B., Zandonà, A., Helsch, G., & Deubener, J.
    Co2+-Stuffed Quartz Solid Solutions With Zero Thermal Expansion Synthesized by Sol-Gel Spray-Drying
    Glass Europe1 (2023) 25–36
    doi.org/10.52825/glass-europe.v1i.460

    Abstract
    Glassy nanobeads of nominal composition CoO·Al2O3·4SiO2, doped with some Li2O to foster their crystallization, were synthesized by spray-drying from a methanol-based solution. Heat treatments at 850 °C and 900 °C successfully induced the formation of quartz solid solution crystals, whose thermal expansion was found to be very close to zero between 25 °C and 625 °C (average linear coefficient of thermal expansion CTE = 0.3 x 10-6 K-1). Annealing at higher temperatures induced structural unstuffing of the solid solutions, accompanied by the parallel formation of CoAl2O4 spinel and by a color shift of the powders from purple to blue. Sol-gel spray-drying stands out as a highly versatile synthesis method that can harness the thermal expansion tunability of quartz solid solution phases within a (quasi) lithium-free compositional landscape.
     

  • Zandonà, A., A. Scarani, J. Löschmann, M.R. Cicconi, F. Di Fiore, D. de Ligny, J. Deubener, A. Vona, M. Allix, D. Di Genova
    Non-stoichiometric crystal nucleation in a spodumene glass containing TiO2 as seed former: Effects on the viscosity of the residual melt
    Journal of Non-Crystalline Solids 619 (2023) 122563, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2023.122563.
    (https://www.sciencedirect.com/science/article/pii/S0022309323004295)

    Abstract
    A spodumene glass (LiAlSi2O6), doped with 4 mol% TiO2 as a nucleating agent, was synthesized by containerless melting. Its accurate viscosity characterization by micropenetration viscometry or calorimetry is shown to be very challenging in the vicinity of the glass transition, due to the unpreventable occurrence of thermally activated non-stoichiometric crystal nucleation, closely overlapping the relaxation into the liquid state. TiO2 crystal nucleation brings about a compositional modification of the residual melt, with an associated increase in measured viscosity by up to 2 log units. A careful experimental approach and a profound understanding of seed formation are essential to circumvent or at least minimize such inaccuracies, getting as close as possible to the viscosity of the parent homogeneous melt.
     

  • Gomes Fernandes, R., Al-Mukadam, R., Bornhöft, H., Reinsch, S., Müller, R., Selle, S., Deubener, J.
    Viscous Sintering of Acid Leached Glass Powders
    Glass Europe 1 (2023) 37–53
    doi.org/10.52825/glass-europe.v1i.681

    Abstract
    The process of viscous flow sintering is a phenomenon that is closely linked to the surface properties of the glass particles. In this work, we studied the extreme case of acid-leaching of soda-lime-silicate glass beads of two different particle size distributions and its effects on non-isothermal viscous sintering of powder compacts. Depth profiling of the chemical composition after leaching revealed a near-surface layer depleted in alkali and alkaline earth ions, associated with concurrent hydration as mass loss was detected by thermogravimetry. Heating microscopy showed that acid treatment of glasses shifted the sinter curves to higher temperatures with increasing leaching time. Modelling of the shrinkage with the cluster model predicted a higher viscosity of the altered surface layer, while analysis of the time scales of mass transport of mobile species (Na+, Ca2+ and H2O) during isochronous sintering revealed that diffusion of Na+ can compensate for concentration gradients before sintering begins. Also, exchanged water species can diffuse out of the altered layer, but the depletion of Ca2+ in the altered surface layer persists during the sinter interval, resulting in a glass with higher viscosity, which causes sintering to slow down.
     

  • Selle, S., Bornhöft, H., Wendel, J. C., Deubener, J.
    Overview of the Precipitates in a Ground-Coat Vitreous Enamel Using Analytical TEM
    Glass Europe, 2, 95–114
    doi.org/10.52825/glass-europe.v2i.1269

    Abstract
    Precipitates in the ground-coat vitreous enamel, which form when the dried coating is fired and cooled on sheet steel, are essential for the function of the enamelling. They lead to an interlocked metal-glass interface and are triggered by redox-driven processes in a glass layer saturated with iron. Using analytical transmission electron microscopy, it is shown that alloys of the Fe-Co-Ni-Cu system not only precipitate near the interface, where they contribute to adhesion through an interlocking interface, but also form nanocrystallites that are finely distributed in the enamelled glass to a depth determined by the diffusivity of Fe2+ (30 μm after four minutes of firing) and probably contribute to the toughening of this glass layer. The saturation with iron also prevents the segregation of the glass flux and opacifier calcium fluoride, which only occurs far from the interface in the chemically unmodified base glass. At the metal-glass interface, however, phosphorus traces diffuse from the steel and precipitates in the form of calcium phosphate needles that grow into the enamelled glass.
     

2022

  • Scarani, A., Vona, A., Di Genova, D. Al-Mukadam, R., Romano, C., Deubener, J.
    Determination of cooling rates of glasses over four orders of magnitude.
    Contrib Mineral Petrol177, 35 (2022).
    doi.org/10.1007/s00410-022-01899-5

    Abstract
    Volcanic materials can experience up to eleven orders of magnitude of cooling rate (qc) starting from 10–5 K s−1. The glassy component of volcanic material is routinely measured via differential scanning calorimeter (DSC) to obtain qc through the determination of the glass fictive temperature (Tf). Conventional DSC (C-DSC), which has been employed for decades, can only access a relatively small range of qc (from ~ 10–2 to ~ 1 K s−1). Therefore, extrapolations up to six orders of magnitude of C-DSC data are necessary to derive qc of glasses quenched both at extremely low and high qc. Here, we test the reliability of such extrapolations by combining C-DSC with the recently introduced flash calorimetry (F-DSC). F-DSC enables to extend the qc exploration up to 104 K s−1. We use three synthetic glasses as analogs of volcanic melts. We first apply a normalization procedure of heat flow data for both C-DSC and F-DSC to derive Tf as a function of experimental qc, following the “unified area-matching” approach. The obtained Tf–qc relationship shows that Arrhenius models, widely adopted in previous studies, are only valid for qc determination within the calibration range. In contrast, a non-Arrhenius model better captures qc values, especially when a significant extrapolation is required. We, therefore, present a practical “how-to” protocol for estimating qc using DSC.
     

  • Bornhöft, H., Deubener J.
    Enamelling ability and adherence of enamels on heterogeneous types of steel with varying proportions of accompanying elements
    Email – Mitteilungen des Deutschen Emailverbandes e.V. 70 (2022) 4-18
    Report available: www.tib.eu/de/suchen/id/TIBKAT:1809317940/Emaillierf%C3%A4higkeit-und-Haftung-von-Emails-auf-heterogenen

    Abstract
    Various European manufacturers provided 21 different types of sheet steel suitable for enamelling. Two commercially available ground enamels (RTU, Ready To Use) and a direct white enamel (RTU) from two enamel frit manufacturers were used in the experiments. Enamelling of the test specimens was performed in an electric furnace with increasing firing duration. The characterization comprised the primary adherence test by deep drawing the enamelled sheet steel using a standard testing machine. The adherence properties were determined based on the type and extent of the destroyed enamel surface and the quantification of the adherence layer proportions. By scanning the fracture pattern and computer-aided evaluation, the results were calculated as an adherence index, with 100 percent being the target value as complete coverage with an adherence layer. The electron microscopic examination of polished sections of all test specimens included the topographical representation of sheet steel, adherence layer and enamel as well as the recording of chemical profiles with 16 relevant elements using EDX from the steel into the enamel layer.
    From the large number of individual investigations, it was possible to gain important information on the reactions occurring during firing and on the formation of the adherence layer between sheet steel and enamel, and compared them with the alloy components present in the sheet steel. According to the state of knowledge achieved up to now, higher alloyed steel sheets (Fe content: 98.6 mass percent) can be enamelled just as perfectly as lower alloyed steel sheets (Fe content: 99.7 mass percent). The quantities of alloying elements that change certain properties of the sheet steel, such as resistance to scaling (e.g. due to the elements silicon or carbon), i.e. the restriction of the oxidizing ability, or a subsequent refinement by phosphatizing to prevent corrosion, are of particular importance for the enamelling ability.
    An important prerequisite for successful enamelling with intensive adherence is the formation of a fresh iron oxide layer on the steel surface, which is formed during the firing process, with immediate dissolution of the FeO in the enamel melt. Depending on the firing duration, a characteristic chemical gradient of the Fe concentration in the enamel is found. This pronounced Fe concentration gradient should ensure a higher fraction of chemical bonds in the form of Fe – O – Si bridges close to the metal-to-enamel interface. In the case of hot-rolled steel sheets, the existing iron oxide layer of several microns must be removed completely before the enamelling, as otherwise, no adherence occurs. Obviously, this “old” iron oxide layer interferes with the redox reactions that take place normally at the surface due to the adherence oxide being present in the ground enamel. The “old” oxide layer is evidently very slow in reacting and hardly dissolves in the melt, or only with time delay. A sufficient amount of fresh FeO can only be formed on the steel if enough oxygen is present in the atmosphere. With the progressive dissolution of FeO a super saturation of iron in the enamel melt occurs and, in presence of adherence metals, alloys can precipitate at the interface showing elevated concentrations of cobalt, nickel and copper. Chemical analyses confirm this precipitation as a secondary formation due to higher amounts of these metals regarding to the base metal. The docking of the precipitated, droplet-shaped aggregating metal alloy phases on the sheet steel surface leads to a characteristic structure with a large specific surface and correspondingly high mechanical interlocking of metal and enamel. The process is supported by the sharp decrease in melt viscosity during the dissolution of FeO in the melt. Tests in an inert gas atmosphere with argon or nitrogen show that the reactions described for the formation of an adherence layer do not occur and therefore no adherence can arise. For this reason, checking the furnace atmosphere with sufficient atmospheric oxygen is of huge importance for the success of the enamelling process.

  • Löschmann,J., Fielitz, P., Helsch,G., Bornhöft, H., Cassar, D.R. , Borchardt, G., Deubener, J.
    Accelerated crystal growth in a lithia aluminosilicate glass
    Acta Materialia (2022) 117837, ISSN 1359-6454,
    doi.org/10.1016/j.actamat.2022.117837.
    (https://www.sciencedirect.com/science/article/pii/S1359645422002245)

    Abstract
    No viscosity change in the vicinity of the crystal/melt interface is to be expected for crystal growth in silicate systems at constant temperature in a deeply undercooled isochemical melt. In most experimental studies, however, absolute chemical conformity is not realized and the formation of an interfacial zone with presumably strongly altered viscosity will occur. In the present investigation isolated Li2O⋅Al2O3⋅4SiO2 (LAS4) single crystals grew in a slightly alumina deficient base glass at temperatures above glass transition. Due to the depletion of alumina (and the enrichment of excess components and impurities) of the continuously growing interfacial zone (“shell”), its viscosity will change. Dedicated experiments showed that the viscosity of the interfacial zone is up to 7 orders of magnitude lower than the viscosity of the base glass. The decreased viscosity at the crystal growth front is assumed to cause the experimentally observed increase of the crystallisation velocity with the crystal radius. This behaviour can be quantitatively modelled introducing a linear decrease of the activation enthalpy with the crystal radius. Obviously, the proposed model can be likewise used in the opposite case, i.e. for an increasing viscosity of the interfacial zone during crystal growth. According to the standard concept of a fractional viscosity relation, a coupling factor can formally be extracted from the comparison between the experimentally determined activation enthalpies of the crystal growth velocity and of the base glass viscosity. The resulting unrealistically low numerical value indicates that it is not the high viscosity of the base glass, but the lower viscosity of the interfacial zone that must be considered for the determination of a physically meaningful coupling factor.
    Keywords: 0non-linear crystal growth kinetics; lithia aluminosilicate glass; glass-ceramics; viscosity

  • C. Tielemann, S. Reinsch, R. Maaß, J. Deubener, R. Müller
    Internal nucleation tendency and crystal surface energy obtained from bond energies and lattice data
    Journal of Non-Crystalline Solids X (2022) 100093, ISSN 2590-1591
    doi.org/10.1016/j.nocx.2022.100093.
    (https://www.sciencedirect.com/science/article/pii/S2590159122000139)
    Abstract
    We present an easy-to-apply method to predict structural trends in the internal nucleation tendency of oxide glasses. The approach is based on calculated crystal fracture surface energies derived from easily accessible diatomic bond energy and crystal lattice data. The applicability of the method is demonstrated on literature nucleation data for isochemically crystallizing oxide glasses.
    Keywords: Glass; Nucleation tendency; Fracture surface energy; Crystal lattice; Bond energy

  • Maiwald, M.; Bornhöft, H., Deubener, J.
    Simultaneous thermal analysis and evolved gas analyses by mass spectrometry on mixtures of steel and ground coat enamel in different atmospheres
    Email – Mitteilungen des Deutschen Emailverbandes e.V. 70 (2022) 24-35

    Abstract
    The method of simultaneous thermal analysis is used to identify reaction processes between steel and ground coat enamel. The thermal behaviour of mixtures of steel chips of different steel grades and one RTU ground coat powder is characterized under the influence of different gas atmospheres (standard air and nitrogen) with regard to mass change, differential thermoanalytical signal and emission of gas as well as gas species. The results of the measurements carried out prove that more intensive exothermic signal curves are recognized when oxygen is present in the measuring atmosphere. However, the thermogravimetric data in air showing a pronounced increase in mass in the range of 5-8 percent up to the end of the test are much more revealing, while in a nitrogen atmosphere only a very small loss in mass in the range of 0.05 to 0.2 percent is measured.
    Gas emissions of the species H2O and CO2 are registered in both measurement atmospheres, although the respective emission peaks are at different temperatures. While adsorbed water shows a peak in the ion current signal at around 100 °C with low intensities, the enhanced emission peaks at temperatures around 450-500 °C are assigned to the released H2O from the decomposition reaction of clay with chemically combined water. In a nitrogen atmosphere, these peaks are shifted to lower temperatures.
    The evaluations of CO2 emissions yield different results that raise questions. A low-intensity CO2 peak is detected in all steel-ground coat mixtures examined both in air at around 280 °C and in N2 at ~310 °C, which is in large part related to the oxidation of organic material from the clay. Of interest is the CO2 gas emission process at temperatures above 550 °C. While some samples show CO2 release (in air and N2) with pronounced peaks, the other steel-ground coat mixtures either lack these peaks or have CO2 ion current signals just barely above background. The reason for this different behaviour is not yet fully understood especially in nitrogen atmosphere. A higher carbon content in the volume of the steel sheets may play a role, while the surface of the enamel steel is largely decarburized. More in-depth analyses of this could no longer be carried out as part of the student project.

  • Fielitz, P., Cassar, D.R., Yuritsyn, N.S., Abyzov, A.S., Fokin, V.M., Borchardt, G., Deubener, J.
    Decelerated crystal growth in a soda-lime-silica glass
    Journal of Non-Crystalline Solids, 596 (2022) 121879, ISSN 0022-3093,
    doi.org/10.1016/j.jnoncrysol.2022.121879.
    (https://www.sciencedirect.com/science/article/pii/S0022309322004744)

    Abstract
    Isolated Na2O⋅2CaO⋅3SiO2 (NC2S3) single crystals grew at temperatures above glass transition in a melt with a slight soda excess. The enrichment of Na in the continuous solid solution Na4+2zCa4–z[Si6O18] (with 0 ≤ z ≤ 1) upon crystallisation causes a depletion of soda of the growing interfacial diffusion zone. Therefore its viscosity will change. Experimental data and idealized model calculations of the viscosity show the same trend and indicate that the viscosity of the interfacial zone would be up to several orders of magnitude higher than the viscosity of the melt. This increased viscosity at the crystal growth front and the experimentally observed decrease of the crystallisation velocity with crystal size suggest a linear increase of the effective activation enthalpy of the diffusional transport through the diffusion zone with crystal size, which allows to quantitatively model crystal growth data of the NC2S3 glass investigated.
     

  • Heuser, L, Nofz, M., Müller, R.,Deubener, J.
    Silver dissolution and precipitation in a Na2O-ZnO-B2O3 metallization paste glass
    Int J Appl Glass Sci. 2022, 2041-1286
    doi.org/10.1111/ijag.16613

    Abstract
    Thermally stimulated interactions between silver and glass, i.e., silver dissolution as Ag+ and precipitation as Ag0 were studied in two glass series of molar target composition xAg2O-(19-x)Na2O-28ZnO-53B2O3 with x = 0, 0.1, 0.5, 5 and (19Na2O-28ZnO-53B2O3)+yAg2O with y = 0.01, 0.05. These act as model for low-melting borate glasses being part of metallization pastes. The occurrence of metallic silver precipitates in melt quenched glass ingots demonstrated that silver dissolved only in traces (< 0.01 mol%) in the glasses. The dissolved silver was detected by means of Raman and EDX spectroscopies. Increasing x in the batch could not lead to a significant increase of the silver ion fraction in the glass as possible in binary silver borate glasses. In situ observation of heated AgNO3 mixed with the base glass frit in a hot stage microscope showed that Ag0 precipitation occurs already at the solid state. At higher temperatures, small droplets of liquid silver were found to move freely within the melt, while coalescence caused a stepwise increase of their size. These results contribute to the understanding of formation of silver precipitates in metallization pastes described in the literature.

     

  • Zandona, A., E. Chesneau, G. Helsch, A. Canizarès, J. Deubener,  V. Montouillout, F. Fayon, M. Allix
    Glass-forming ability and structural features of melt-quenched and gel-derived SiO2-TiO2 glasses
    Journal of Non-Crystalline Solids, 598 (2022) 121967, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2022.121967
    (https://www.sciencedirect.com/science/article/pii/S0022309322005622)

    Abstract
    SiO2-TiO2 glasses produced by aerodynamic levitation coupled to laser heating or by sol-gel spray-drying were compared to highlight their structural differences. Glass formation was possible by melt-quenching up to 10 mol% TiO2, while higher contents led to devitrification. Raman spectroscopy and solid-state 17O and 29Si magic-angle-spinning nuclear magnetic resonance confirmed the clear emergence of Ti-O-Si bonds and a tetrahedral oxygen coordination of Ti4+ leading to full network connectivity, as also substantiated by the synthesis of TiO2-doped cristobalite. In gel-derived glasses, water content induced partial network depolymerization, thereby enhancing the solubility of TiO2 in the hydrous silicate matrix. However, full dehydration during heating proved challenging due to a competing tendency towards devitrification: the glass-forming range in the anhydrous binary SiO2-TiO2 system does not therefore appear to be significantly enlarged by the sol-gel synthesis route.

  • Scarani, A.; A. Zandonà, F. Di Fiore, P. Valdivia, R. Putra, N. Miyajima, H. Bornhöft, A. Vona, J. Deubener, C. Romano, D. Di Genova
    A chemical threshold controls nanocrystallization and degassing behaviour in basalt magmas
    Commun Earth Environ 3 (2022) 284
    doi.org/10.1038/s43247-022-00615-2

    Abstract
    An increasing number of studies are being presented demonstrating that volcanic glasses can be heterogeneous at the nanoscale. These nano-heterogeneities can develop both during viscosity measurements in the laboratory and during magma eruptions. Our multifaceted study identifies here total transition metal oxide content as a crucial compositional factor governing the tendency of basalt melts and glasses towards nanolitization: at both anhydrous and hydrous conditions, an undercooled trachybasalt melt from Mt. Etna readily develops nanocrystals whose formation also hampers viscosity measurements, while a similar but FeO- and TiO2-poorer basalt melt from Stromboli proves far more stable at similar conditions. We therefore outline a procedure to reliably derive pure liquid viscosity without the effect of nanocrystals, additionally discussing how subtle compositional differences may contribute to the different eruptive styles of Mt. Etna and Stromboli.
     

2021

  • P. Stabile, S. Sicola, G. Giuli, E. Paris, M.R. Carroll, J. Deubener, D. Di Genova
    The effect of iron and alkali on the nanocrystal-free viscosity of volcanic melts: A combined Raman spectroscopy and DSC study
    Chemical Geology 559 (2021) 119991, ISSN 0009-2541
    https://doi.org/10.1016/j.chemgeo.2020.119991
    (http://www.sciencedirect.com/science/article/pii/S0009254120305301)

    Abstract
    The iron coordination, its oxidation state (Fe2+/Fetot.), and alkali ratio [Na/(Na + K)] greatly influence the structure and thus the viscosity of volcanic melts, which is known to play a key role in the dynamics of volcanic eruptions. Furthermore, it has been recently reported that volcanic melts can suspend iron-bearing nanocrystals and this makes it difficult to isolate and quantify the chemical contribution to the viscosity of magmas.
    Here, we present Raman spectroscopic and differential scanning calorimetry (DSC) data on nanocrystal-free peralkaline rhyolites with different Fe2+/Fetot. (0.15–0.84) and Na/(Na + K) (0–1) molar ratios. Raman spectra are used to infer the structural changes occurring with varying iron oxidation state and alkali content, whereas the combination of Raman spectroscopy and DSC measurements allow the characterization of the anhydrous nanocrystal-free viscosity as a function of temperature. Results suggest that at similar and high Fe2+/Fetot. ratio the Raman spectral feature controlled by the iron coordination changes with Na/(Na + K). Conversely, the change of alkali content at a fixed Fe2+/Fetot. ratio results in a variation of the spectral feature that reflects the size distribution of rings of tetrahedra in the melt structure.
    We further discuss the implications of our findings for magma transport and estimate that the viscosity of anhydrous peralkaline rhyolites at the eruptive temperature of 750 °C can increase up to 3.5 log units when Fe2+/Fetot. and Na/(Na + K) ratios decrease contemporaneously from 0.84 to 0.15 and from 1 to 0, respectively. Finally, the comparison of our viscosity data with those from the literature suggests that the DSC-approach presented and adopted in this study is independent on chemical composition and thus can be used also to retrieve the effect of nanocrystals on the viscosity of volcanic melts. The results presented here have profound implications for the modelling of magma viscosity.
    Keywords: Peralkaline rhyolites; Raman spectroscopy; Alkali effect; Iron oxidation state; Viscosity

     
  • R. Al-Mukadam, A. Zandona, J. Deubener
    Kinetic fragility of pure TeO2 glass
    Journal of Non-Crystalline Solids 554 (2021) 120595
    https://doi.org/10.1016/j.jnoncrysol.2020.120595

    Abstract:
    Pure TeO2 glass was prepared in a flash differential scanning calorimeter by applying fast quenching rates to a TeO2 melt. Matching cooling and heating rates of up to 30,000 K s−1 were then used to determine the respective fictive temperatures, corresponding to viscosity values as low as 105.3 Pa s. The interdependence between calorimetric data and viscosity was verified and fine-tuned for this compositional system utilizing sodium tellurite glasses. The fragility index of pure TeO2 (m = 64) is by far the highest reported for a single-component oxide melt.
    Keywords: Glass; TeO2; Sodium tellurite; FDSC; Fragility; Viscosity
     

  • A. Zandona, G. Helsch, A. Martínez Arias, AP. Weber, J. Deubener
    Spray-dried sol-gel glass-ceramic powders based on the tunable thermal expansion of quartz and keatite solid solutions
    J Am Ceram Soc. 2021; 00: 1– 10.
    https://doi.org/10.1111/jace.18057

    Abstract
    Lithium aluminosilicate glass-ceramic powders were synthesized by the heat treatment of spray-dried sol-gel glassy nanobeads, obtaining quartz solid solution (Qss) and keatite solid solution (Kss) crystals. Their composition ranged between 75 mol% SiO2 and pure silica along the spodumene join. The metastable crystals displayed tunable coefficients of thermal expansion ranging from +30 × 10−6 to −2.7 × 10−6 K−1 at room temperature, as obtained from their crystallographic characterization. The solid solution boundaries of Kss could be extended to 85 mol% SiO2. Concurrently, X-ray diffraction measurements performed in situ at high temperature and at cryogenic conditions confirmed the known linear shift of the high-low quartz inversion temperature upon increasing Al+Li doping. The obtained results qualify aerosol synthesis as a very versatile method for the production of glass-ceramic powders in the LAS system.
     

  • T. Waurischk, S. Reinsch, T. Rouxel, H. Behrens, J. Deubener, R. Müller
    Vacuum crack growth in alkali silicate glasses
    Journal of Non-Crystalline Solids 572 (2021) 121094, ISSN 0022-3093,
    https://doi.org/10.1016/j.jnoncrysol.2021.121094.
    (https://www.sciencedirect.com/science/article/pii/S0022309321004579)

    Abstract
    Crack growth velocity in alkali silicate glasses was measured in vacuum across 10 orders of magnitude with double cantilever beam technique. Measured and literature crack growth data were compared with calculated intrinsic fracture toughness data obtained from Young´s moduli and the theoretical fracture surface energy estimated from chemical bond energies. Data analysis reveals significant deviations from this intrinsic brittle fracture behavior. These deviations do not follow simple compositional trends. Two opposing processes may explain this finding: a decrease in the apparent fracture surface energy due to stress-induced chemical changes at the crack tip and its increase due to energy dissipation during fracture.

  • Zerong Yang, Raschid Al-Mukadam, Moritz Stolpe, Matthias Markl, Joachim Deubener, Carolin Körner,
    Isothermal crystallization kinetics of an industrial-grade Zr-based bulk metallic glass,
    Journal of Non-Crystalline Solids 573 (2021) 121145, ISSN 0022-3093,
    https://doi.org/10.1016/j.jnoncrysol.2021.121145
    (https://www.sciencedirect.com/science/article/pii/S0022309321005081)

    Abstract
    Bulk metallic glasses (BMGs), due to their amorphous structure, exhibit remarkable mechanical properties, and there is an increasing interest in their commercialization. For the industrial fabrication of BMG, knowledge about the isothermal crystallization kinetics of industrial-grade BMG is required. Previous investigations on isothermal crystallization kinetics are mainly based on high-purity samples with very good glass forming ability and/or mainly limited to the low temperature regime. In the present study, a systematic investigation on the isothermal crystallization kinetics of an industrial-grade Zr-based BMG (Zr59.3Cu28.8Al10.4Nb1.5 at.%, trade name: AMZ4) has been performed using conventional and flash differential scanning calorimetry. We report the time-temperature-transformation (TTT) diagrams of the AMZ4 with two different oxygen levels. The diagrams cover the temperature range from glass transition temperature up to liquidus temperature, that have the typical “C-shaped” noses. Faster crystallization of the higher oxygen level AMZ4 was observed, and the underlying mechanisms were investigated. The universal isothermal Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was employed to model the isothermal crystallization kinetics. Satisfactory match was achieved between the experimental facts and the JMAK model, and the interfacial energies between the crystalline phase and liquid were determined as ∼0.04 J/m2 for the industrial-grade AMZ4. The crystallization fraction dependence of Avrami index and activation energy is studied and found to be neglectable in the JMAK modeling. The critical casting thicknesses were estimated based on the TTT diagrams.
    Keywords: Crystallization kinetics; Bulk metallic glass; JMAK Model; Classical nucleation theory; Time-temperature-transformation diagram; Fast scanning calorimetry; Selective laser melting

  • Bornhöft, H., A. Zellmann, J. Deubener
    Kinetics of the adherence layer formation of direct white enamel on sheet steel with a layer of Cobalt, deposited without external current as well as electrolytically
    Email – Mitteilungen des Deutschen Emailverbandes e.V. 69 (2021) 56-71

    Abstract
    In a previous issue of the email-Mitteilungen [BOR2021] it is reported about the chronological sequence of the adherence layer development of direct white enamel (DWE) during firing after pre-treatment of the steel sheet after dipping into a nickel sulphate bath (Ni-DIP). The focus of this work is the investigation of the development of the adherence layer in direct white enamelling using cobalt as the adherence element deposited on the surface of the steel sheet. On the one hand, the coating with cobalt was carried out without external current, analogous to the nickel DIP process, and on the other hand, an electrolytic method was used due to a better deposition rate.
    Depending on the coating method, different results arise in the layer application, which is of decisive importance for the subsequent enamelling and the development of the adherence layer. Subsequently, by means of different firing duration on DWE sheet steel plates, the enamel adherence could be tested and assessed by means of deep drawing the sheets.
    The microstructure at the metal-enamel interface was examined using scanning electronic microscopy and element-specific X-ray analysis (EDX). It is found that the coating with cobalt on the steel sheet surface does not prevent diffusion of iron ions into the enamel melt during firing. The diffusion behaviour can be described by means of a root-time dependency.
    Depending on the deposition process used, deposited cobalt can be detected in an increased concentration at the steel-enamel interface. Together, it is found that the cobalt deposited on the steel sheet remains in the adherence layer and does not diffuse further into the enamel layer. Before coating with cobalt, a pickling process is necessary to ensure good deposition. The adherence of the direct white enamel starts after a very short firing duration of the steel sheet (thickness 1 mm) treated with cobalt and reaches a maximum value after about 3-5 minutes. The investigations confirm an adherence mechanism that is based on the formation of crystalline structures in the form of ilmenite (FeTiO3) at the metal-enamel interface.

  • R. Al-Mukadam, I.K. Götz, M. Stolpe, J. Deubener,
    Viscosity of metallic glass-forming liquids based on Zr by fast-scanning calorimetry
    Acta Materialia,
    Volume 221, 2021, 117370, ISSN 1359-6454, https://doi.org/10.1016/j.actamat.2021.117370
    (https://www.sciencedirect.com/science/article/pii/S1359645421007497)

    Abstract
    Fast-scanning calorimetry was applied to retrieve the viscosity of supercooled liquids of the Zr-based bulk metallic glasses (BMGs) Vitreloy 105 and AMZ4 for temperatures from standard glass transition down to ∼0.78Tg/T. Characteristic temperatures of the glass transition were translated into viscosity values by means of composition-independent shift factors based on the equivalency between structural relaxation and viscous flow. The extended MYEGA model with a fragile term dominant at high-temperatures and a strong term dominant at low-temperatures describes the entire viscous range. The analysis revealed that Vitreloy 105 and AMZ4 are strong liquids for log10η ≥ 4.9–5.5. In turn, the fragile-to-strong crossover is centred on 0.69Tg/T for Vitreloy 105 and on 0.66Tg/T for AMZ4. The extent of the fragile-to-strong transition was found to be larger for Vitreloy 105 than for AMZ4, while their values agreed well with the inverse relation between transition factor and kinetic fragility of the strong regime established for BMG-forming liquids.
    Keywords: BMG; Vitreloy 105; AMZ4; Viscosity; Fragility; Fragile-to-strong crossover; Fast-scanning calorimetry
     

  • Ehrenberg, A., N.R. Sarcos, D. Hart, H. Bornhöft, J. Deubener
    Dry and wet granulation of blast furnace slag and their influence on its reactivity
    Cement International 19 (2021) 40-51 (Part 1); 54-62 (Part 2)

    Abstract
    The transformation of liquid blast furnace slag into granulated blast furnace slag usually takes place via wet granulation, i.e. the fragmentation and abrupt cooling of the liquid slag by means of a high excess of water. This ensures a generally very high glass content, which is the prerequisite for the latent hydraulic behaviour of the blast furnace slag. The disadvantage of this is that granulated blast furnace slag has about 10 mass % residual moisture and, in particular, that the high heat content of the liquid slag cannot be utilised. For about ten years, therefore, more and more work has been done on plants that are intended to achieve dry cooling of the liquid blast furnace slag to a glassy material. In the years 2009 to 2019, the FEhS Institute was involved in several such projects. It was found several times that dry-produced blast furnace slag was less reactive than conventionally produced slag despite a comparably high glass content. The explanation for this behaviour could be found in a research project worked on with the Clausthal University of Technology to determine the fictive temperature, i.e. the real "freezing temperature" of the liquid blast furnace slag to glass, as well as the subsequent calculation of the cooling rate previously realised under practical conditions. It could be demonstrated that blast furnace slag particles of comparable size have a higher cooling rate, a higher fictive temperature and a higher enthalpy content when produced wet. Furthermore, parallel investigations on conventionally produced granulated blast furnace slags were able to demonstrate for the first time a concrete correlation between the fictive temperature as a measure of the enthalpy content of the granulated blast furnace slag and its reactivity in a cementitious system.
     

2020

  • P. Kiefer, J. Deubener, R. Müller, H. Behrens
    Statistical analysis of propagation rates of indentation-induced radial cracks in soda-lime-silica glass
    Journal of Non-Crystalline Solids 527 (2020) 119739
    https://doi.org/10.1016/j.jnoncrysol.2019.119739
    ISSN 0022-3093
    (https://www.sciencedirect.com/science/article/pii/S002230931930609X)

    Abstract:
    Due to the stochastic nature of crack nucleation by Vickers indentation, a statistical analysis of propagation rates of 185 radial cracks was performed. Crack growth was observed directly using a video camera with high image acquisition rate. It is found that propagation rates are controlled by the environmental reactions at the crack-tip shortly after their initiation (< 1 s). Calibration of the stress intensity KI showed that the residual stress factor χ and the exponent n of the equation KI = =χPc−n (with P = =load and c = =crack length) are broadly distributed among the 185 analyzed cracks, ranging from 10−16 to 104 and from 0.1 to 5, respectively. For the most frequent crack, the equation KI = =0.052Pc−1.47 holds. The results show that correlations of indentation-induced crack length to stress intensity necessitate the use of statistical significant data that are calibrated by the environmental reactions at the crack-tip.
    Keywords: Vickers indentation; Subcritical crack growth; Soda-lime-silica glass; Stress intensity factor
     
  • T. Welter, R. Müller, J. Deubener, U. Marzok, S. Reinsch
    Hydrogen Permeation Through Glass
    Frontiers in Materials 6 (2020) 342  
    (https://www.frontiersin.org/article/10.3389/fmats.2019.00342)
    https://doi.org/10.3389/fmats.2019.00342
    ISSN: 2296-8016  

    Abstract
    Physical storage of gaseous hydrogen under high-pressure in glassy micro-containers such as spheres and capillaries is a promising concept for enhancing safety and the volumetric capacity of mobile hydrogen storage systems. As very low permeation through the container wall is required for storage of compressed hydrogen, development of glasses of minimal hydrogen permeability is needed. For this purpose, one has to understand better the dependence of hydrogen permeability on glass structure. The paper points out that minimizing the accessible free volume is a sound strategy to minimize hydrogen permeability. Based on previously measured and comprehensive literature data, it is shown that permeation is independently controlled by ionic porosity and network modifier content. Thus, ionic porosity in modified and fully polymerized networks can be decreased equally to the lowest hydrogen permeability among the glasses under study. Applying this concept, a drop of up to 30,000 with respect to the permeation of hydrogen molecules through silica glass is attainable.
     
  • L.C. Briese, S. Selle,  J. Deubener, T. Höche
    Formation of ε-Co nanocrystals in borosilicate and aluminosilicate glasses
    Journal of Non-Crystalline Solids 535 (2020) 119961
    https://doi.org/10.1016/j.jnoncrysol.2020.119961
    ISSN 0022-3093
    (https://www.sciencedirect.com/science/article/pii/S0022309320300788)

    Abstract
    Formation of cobalt nanocrystals in durable borosilicate and aluminosilicate glass matrices is studied. Using a hydrogen gas flow treatment, ε-Co nanocrystals precipitate primarily in these glasses. This rare Co allotrope, which so far has mainly been synthetized by organometallic routes is found for the first time in a glass. XRD and TEM results indicate that ε-Co is present in glasses ≥ 500 °C and that it successively transforms into the more stable α- and β-Co allotropes. Primary formation of the ε-Co in glasses is in agreement with the Ostwald-Volmer rule of stage as it yields the lowest density change with respect to the parent glass among the three Co allotropes.
    Keywords: Epsilon (ε) cobalt; Nanocrystals; Borosilicate glass; Aluminosilicate glass; Hydrogen gas treatment
     
  • R. Al-Mukadam, D. Di Genova, H. Bornhöft, J. Deubener
    High rate calorimetry derived viscosity of oxide melts prone to crystallization
    Journal of Non-Crystalline Solids, 536 (2020) 119992
    https://doi.org/10.1016/j.jnoncrysol.2020.119992
    ISSN 0022-3093
    (https://www.sciencedirect.com/science/article/pii/S0022309320301095)

    Abstract
    A gap in viscosity data spreads between glass transition and liquidus temperature for glass compositions, which are prone to crystallization. Alternatively, differential scanning calorimetry (DSC) is used to calculate viscosity as both the cooling rate in a DSC experiment and the shear viscosity at the fictive temperature are related by a constant shift factor. However, the low cooling rate (≤ 30 K min−1) of conventional calorimeters limits the accessible range of viscosities around 1012 Pa s. This study reports on measurements using a Flash DSC (FDSC) with cooling rates up to 3 × 105 K min−1. Under such extreme conditions, the fictive temperature is shifted considerably to higher temperatures and viscosity is accessible down to the softening point (viscosity = 106.6 Pa s) without the occurrence of crystallization during measurements. We provide a composition-independent shift factor to retrieve the viscosity of silicate and fluorophosphate melts over six orders of magnitude.
    Keywords: Fast scanning calorimetry; Flash DSC; Viscosity; Lithium disilicate glass; Diopside glass; Fluorophosphate glass
     
  • Ehrenberg, A.*, Romero Sarcos, N., Hart, D., Bornhöft, H., Deubener, J.
    * FEhS – Institut für Baustoff-Forschung E.V.
    Influence of the Thermal History of Granulated Blast Furnace Slags on Their Latent Hydraulic Reactivity in Cementitious Systems
    J. Sustain. Metall. 6 (2020) 207-215
    https://doi.org/10.1007/s40831-020-00269-4

    Abstract
    Together with about 1180 million tons of hot metal (2017) about 380 million tons of blast furnace slag are produced yearly worldwide. Most of it (about 280 million tons) is quenched forming the glassy granulated blast furnace slag (GBS). For more than 130 years, this by-product is used as a clinker substitute in cement and concrete. Many approaches exist to evaluate the reactivity of ground granulated blast furnace slag (GGBS) in cementitious systems based on glass content, chemical composition, fineness, etc. But all approaches fail to define a suitable tool for judging an unknown GBS in a way that its strength contribution can be predicted. Only a rough differentiation might be possible. Compared to other parameters influencing GBS reactivity, the thermal history and the glass structure are mostly not investigated so far. However, from thermodynamic and kinetic points of view it is obvious that the thermal history of the slag should have a significant influence on glass structure and reactivity. The basic idea of the research project was to use analytical techniques being already established, for example, lime–soda–silica glasses. The differential scanning calorimetry and viscosity measurements have been combined for GBS characterization in order to measure the fictive temperature Tf (glass transition temperature on cooling during industrial quenching process) and to calculate retroactively the unknown cooling rates of liquid slags. Using these methods in combination with classical cementitious tests, it was possible to verify a correlation between the thermal history of GBS and its reactivity in a cementitious system.
    Keywords: Granulated blast furnace slag, Cement, Glass transition temperature, Fictive temperature, Granulation process, Slag valorization
     

  • L.C. Briese, J. Deubener, S. Selle, T. Höche
    Thermal expansion of ε-Co and β-Co nanocrystals in glass matrices
    Materials Letters, Volume 270 (2020) 127707
    https://doi.org/10.1016/j.matlet.2020.127707
    ISSN 0167-577X
    (http://www.sciencedirect.com/science/article/pii/S0167577X20304122)

    Abstract
    Metastable ɛ-Co nanocrystals precipitate in silicate glass matrices together with stable β-Co nanocrystals at temperatures up to 873 K, whereas rapid thermal decomposition of ε-Co is reported if formed by wet-chemical routes. Hence, high-temperature X-ray diffraction was used to determine the unknown coefficient of thermal expansion (CTE) of ε-Co stabilized in glasses. The liquid character of the matrix provides free expansion of ε-Co nanocrystals above the glass transition temperature (Tg), while a strain correction was performed for lattice constants below Tg using the co-precipitated β-Co as internal reference. It is found that CTE (298–873 K) of ε-Co nanocrystals is 10.1 ppm K−1, which is slightly larger than CTE of β-Co nanocrystals (9.4 ppm K−1).
    Keywords: Epsilon (ε) cobalt; Beta (β) cobalt; Nanocrystals; Coefficient of thermal expansion (CTE); Glass matrix
     

  • T. Waurischk, R. Müller, S. Reinsch, P. Kiefer, J. Deubener, R. Balzer, H. Behrens
    Crack Growth in Hydrous Soda-Lime Silicate Glass  
    Frontiers in Materials 7 (2020) 66
    https://doi.org/10.3389/fmats.2020.00066
    ISSN 2296-8016
    www.frontiersin.org/article/10.3389/fmats.2020.00066

    Abstract
    Stable crack growth was measured for nominal dry and water-bearing (6 wt%) soda-lime silicate glasses in double cantilever beam geometry and combined with DMA studies on the effects of dissolved water on internal friction and glass transition, respectively. In vacuum, a decreased slope of logarithmic crack growth velocity versus stress intensity factor is evident for the hydrous glass in line with an increase of β-relaxation intensity indicating more energy dissipation during fracture. Further, inert crack growth in hydrous glass is found to be divided into sections of different slope, which indicates different water related crack propagation mechanism. In ambient air, a largely extended region II is observed for the hydrous glass, which indicates that crack growth is more sensitive to ambient water.
     

  • R. Balzer, H. Behrens, T. Waurischk, S. Reinsch, R. Müller, P. Kiefer, J. Deubener, M. Fechtelkord
    Water in Alkali Aluminosilicate Glasses
    Frontiers in Materials 7, (2020) 85
    ISSN 2296-8016, Frontiers Media SA,
    https://doi.org/10.3389/fmats.2020.00085

    Abstract
    To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of <4 wt%, and molecular water becomes dominating at water content of >5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses.
     

  • D. Di Genova, A. Zandona, J. Deubener
    Unravelling the effect of nano-heterogeneity on the viscosity of silicate melts: Implications for glass manufacturing and volcanic eruptions
    Journal of Non-Crystalline Solids 545 (2020) 120248, ISSN 0022-3093,
    https://doi.org/10.1016/j.jnoncrysol.2020.120248
    (https://www.sciencedirect.com/science/article/pii/S0022309320303616)

    Abstract
    Traditionally depicted as homogeneous materials, manmade and volcanic glasses are often subjected to nanostructuration during demixing and crystallization of their parental melt. While the controlled formation of nanocrystals has been exploited for decades in the industrial production of glass-ceramics to obtain materials with superior properties, nano-heterogeneities have been recently recognized in volcanic products erupted explosively. Here, a multi-pronged approach is adopted to highlight how the emergence of nano-heterogeneities exerts a previously unexplored influence on the viscosity of multicomponent silicate melts. Calorimetry and viscometry provide evidence of how the formation of TiO2- and FeO-bearing nanocrystals increases the effective viscosity of suspensions. Raman spectroscopy and transmission electron microscopy allow the correlation between the increase in viscosity and the degree of sample modification. This study has implications for glass and glass-ceramics manufacturing and for the development of better numerical models of volcanic eruptions, which are key for the operational assessment of volcanic risk.
    Keywords: Glasses; Nanoceramics; Crystallization; Nanocrystals; Viscosity; Volcanoes
     

  • A. Zandona, B. Rüdinger, O. Hochrein, J. Deubener
    Chemical gradients at the surface of TiO2-doped cordierite glass-ceramics
    Journal of Non-Crystalline Solids, 547 (2020) 120298, ISSN 0022-3093,
    https://doi.org/10.1016/j.jnoncrysol.2020.120298
    (http://www.sciencedirect.com/science/article/pii/S0022309320304105)

    Abstract
    After crystallizing monolithic cordierite glass samples nucleated by TiO2, ToF-SIMS, GI-XRD and Raman spectroscopic measurements were performed on their surface. Compositional gradients (Mg and Al depletion, Si and Ti enrichment) and a different crystalline assemblage from the one in the interior were identified. The Al-Si ordering process during the indialite-cordierite phase transition appeared moreover to proceed slower on the surface. These differences were absent in the TiO2-free reference sample; they were therefore related to the role of TiO2 as a nucleating agent and to the resulting crystallization sequence. In addition, similar effects were observed in powders of the same composition as the monoliths.
    Keywords: Magnesium aluminosilicate glasses; Glass-ceramics; Surface effects; Cordierite; Si-Al ordering
     

  • A. Zandona, G. Helsch, J. Deubener
    Inversion of quartz solid solutions at cryogenic temperatures
    Journal of the American Ceramic Society, 2020
    https://doi.org/10.1111/jace.17393
    doi.org/10.1111/jace.17393

    Abstract
    Quartz solid solution crystals of six different compositions were obtained from crystallization of glass powders belonging to the Li2O–Al2O3–SiO2 (LAS) system. They were analysed in‐situ by laboratory‐based X‐ray diffraction down to cryogenic temperatures (‐190 °C). Temperature‐resolved analysis of their lattice parameters allowed determination of the critical inversion temperature Tc in these materials, marking the displacive phase transition from a high‐quartz‐ to a low‐quartz‐like lattice. Integrating available data from other literature sources, an updated phase diagram for the occurrence of high and low quartz solid solution phases is provided for the LAS system; this data is expected to support future development of functional materials relying on these crystalline phases.
    Keywords: cryogenics, LAS glass-ceramics, quartz inversion, quartz solid solution, X-ray diffraction
     

  • D.V. Okhrimenko, C.F. Nielsen, L.Z. Lakshtanov, K.N. Dalby, D.B. Johansson, M. Solvang, J. Deubener, S.L.S. Stipp
    Surface Reactivity and Dissolution Properties of Alumina–Silica Glasses and Fibers
    ACS Appl. Mater. Interfaces, 2020
    https://doi.org/10.1021/acsami.0c09362
    doi.org/10.1021/acsami.0c09362

    Abstract
    The ability of bulk glass and fibers to react in aqueous solution, with organic polymers and coupling agents, depends on the surface charge, reactivity, and adsorption properties of the glass surface, i.e. the character and density of surface −OH groups, whereas glass and fiber chemical stability and biosolubility depend on the resistance to dissolution. If glass dissolution products are accumulated in a media, they can change the surface properties by specific adsorption. We determined the −OH surface concentration, reactivity, adsorption, and dissolution properties of aluminosilicate glasses containing various modifiers and compared the results with the behavior of complex mineral wool fibers. Using proton consumption and element release from batch surface titration experiments, over the range 5 < pH < 10, surface −OH adsorption properties were modeled with the FITEQL program. During titration, network modifiers in the glass subsurface are preferentially replaced by protons, resulting in cation accumulation in the solution and formation of a leached layer enriched with Si on the solid. The behavior of Al was different. At 5 < pH < 9, only very small amounts of Al were found in the leachates, which can be explained by almost complete Al adsorption as stable surface complexes, i.e. >XOAl(OH)2 (where X = Si or Al and > represents the surface). At pH > 9, divalent cations adsorbed specifically, as >XOMe+ complexes (Me = Ca or Mg). This deeper understanding of the surface behavior of glasses and fibers is important for the design of composite materials, for applications in biology and medicine and in materials production in general, as well as for understanding natural processes, such as global uptake estimates of CO2 during rock weathering.
    Keywords: surface titration, surface complexation, glass corrosion behavior, glass surface, fibers
     

  • R.G. Fernandes, S. Selle, T. Wagner, M. Menzel, H. Bornhöft, T. Höche, J. Deubener
    Local relative density fluctuation in the early stage of a sintered glass sphere compact determined by X-ray computed tomography
    Journal of Non-Crystalline Solids (2020) 120316, ISSN 0022-3093
    https://doi.org/10.1016/j.jnoncrysol.2020.120316
    (http://www.sciencedirect.com/science/article/pii/S0022309320304282)

    Abstract
    The relative density of a sintered glass-powder compact varies at the local level due to its heterogeneous nature, which makes its characterization essential. In this work, high-resolution X-ray computed tomography (XCT) was used to quantitatively characterize the local relative density fluctuation of a sintered glass compact in its initial stage. The degree of heterogeneity of the microstructure was calculated taking into account the coarseness parameter. With a basis of 23,500 particles scanned in the representative volume element (RVE), the local environment was subdivided into three different groups of particles, represented by a cubic cell with a volume equivalent to that of approximately 600, 80 and 10 spherical particles with a diameter of 80 μm. Independent of the particle group analysed, we found that the maximum of the local relative density distributions, which could be described by a normal distribution function, always occurs around the relative density of the RVE. However, the fluctuation of the data showed a considerable change regarding the width, which increases as the volume of the analysed group of particles decreases, suggesting that particle packing is more heterogeneous on a small scale. In particular, we observed that the heterogeneity of the microstructure for the RVE under consideration becomes pronounced for groups of approximately 10 to 80 particles.
    Keywords: Viscous flow sintering; Heterogeneous microstructure; Local relative density fluctuation; Coarseness; X-ray computed tomography
     

  • P. Kiefer, M. Maiwald, J. Deubener, R. Balzer, H. Behrens, T. Waurischk, S. Reinsch, R. Müller
    Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses
    Frontiers in Materials 7 (2020) 268, ISSN=2296-8016
    https://www.frontiersin.org/article/10.3389/fmats.2020.00268
    doi.org/10.3389/fmats.2020.00268

    Abstract
    To explore the impact of ambient and structural water on static fatigue, the initiation and growth of 3279 Vickers induced median radial cracks were automatically recorded and analyzed. We find that humidity is more efficient in initiating cracks and promoting their growth than water, which is dissolved in the glass structure. In particular for slow crack growth (< 3 × 10–6 m s–1), tests in dry nitrogen showed a considerable decrease in the crack growth exponent with increasing water content of the glasses. On the other hand, if tests were performed in humid air, the crack growth exponent was independent of the water content of the hydrous glasses, while stress intensity decreased slightly. These observations indicate that water promotes the processes at the crack-tip regardless of its origin. However, ambient water is more efficient.
     

  • L.C. Briese, S. Selle, C. Patzig, Y. Hu, J. Deubener, T. Höche
    Compositional study on the size distribution of nickel nanocrystals in borosilicate glasses
    Journal of Non-Crystalline Solids 549 (2020) 120357, ISSN 0022-3093
    https://doi.org/10.1016/j.jnoncrysol.2020.120357
    (http://www.sciencedirect.com/science/article/pii/S0022309320304695)

    Abstract
    For three borosilicate glasses of different B-to-Si ratio, annealed under reducing atmosphere, the effect of glass composition on the size distribution of nickel nanocrystals formed therein was studied. Depth-dependent crystal size distributions were analyzed using transmission electron microscopy, while the glass structure was examined by optical and X-ray absorption spectroscopy (XAS) and related to magnetic measurements using a superconducting quantum interference device (SQUID). A B-to-Si ratio of 0.092 resulted in a uniform crystal size distribution of small width, both with depth and with time, therefore exhibiting a large share of small nanocrystals close to the superparamagnetic limit. XAS and SQUID results indicate a more effective reduction of Ni ions in the glass of higher boron oxide content due to a higher Tg and a mean lower oxidation state induced via lowering of the glass basicity.
    Keywords: Metal nanocluster composite glasses; Nickel nanocrystals; Hydrogen gas-flow treatment; Transmission electron microscopy; Magnetization
     

  • S. Blotevogel, L. Steger, D. Hart, L. Doussang, J. Kaknics, M. Poirier, H. Bornhöft, J. Deubener, C. Patapy, M. Cyr
    Effect of TiO2 and 10 minor elements on the reactivity of ground granulated blast furnace slag (GGBS) in blended cements
    J. Am. Ceram. Soc. (2020)
    https://doi.org/10.1111/jace.17431

    Abstract
    Ground granulated blast furnace slags (GGBS) are glasses (>99%) of the CaO‐Al2O3‐SiO2 compositional system and are widely used as supplementary cementitious materials. Differences in reactivity of GGBS were screened by modifying the content of 11 minor elements (namely Ba, Ce, Cs, Cr, Mn, P, Sn, Sr, Ti, V, Zr). SEM observations showed that most elements entered the silicate glass matrix, only Sn was reduced to its metallic form and P accumulated in minor minerals. Mortar strength tests showed that 2d‐compressive strength was reduced by > 50% for a TiO2 content of 2.5 wt.% in the slag. At 28 days the loss in compressive strength was still > 40%. Calorimetric tests on other element additions showed that network modifiers (Ba, Cs and Sr) and GGBS reactivity are positively correlated, whereas Ce, Cr, V and Zr significantly decreased reactivity. It is shown that these effects can be well estimated by the weighted field strength of the added element.
     

  • D. Di Genova, R.A. Brooker, H.M. Mader, J.W.E. Drewitt, A. Longo, J. Deubener, D.R. Neuville, S. Fanara, O. Shebanova, S. Anzellini, F. Arzilli, E.C. Bamber, L. Hennet, G. La Spina, N. Miyajima
    In situ observation of nanolite growth in volcanic melt: A driving force for explosive eruptions
    Science Advances  23 Sep 2020: Vol. 6, no. 39, eabb0413
    DOI: 10.1126/sciadv.abb0413
    https://dx.doi.org/10.1126/sciadv.abb0413

    Abstract
    Although gas exsolution is a major driving force behind explosive volcanic eruptions, viscosity is critical in controlling the escape of bubbles and switching between explosive and effusive behavior. Temperature and composition control melt viscosity, but crystallization above a critical volume (>30 volume %) can lock up the magma, triggering an explosion. Here, we present an alternative to this well-established paradigm by showing how an unexpectedly small volume of nano-sized crystals can cause a disproportionate increase in magma viscosity. Our in situ observations on a basaltic melt, rheological measurements in an analog system, and modeling demonstrate how just a few volume % of nanolites results in a marked increase in viscosity above the critical value needed for explosive fragmentation, even for a low-viscosity melt. Images of nanolites from low-viscosity explosive eruptions and an experimentally produced basaltic pumice show syn-eruptive growth, possibly nucleating a high bubble number density.
     

  • Zandona, A., B. Rüdinger, J. Deubener
    Mg-bearing quartz solid solutions as structural intermediates between low and high quartz
    Journal of the American Ceramic Society 0002-7820
    https://doi.org/10.1111/jace.17517
    doi:10.1111/jace.17517

    Abstract
    Glass powder samples of cordierite composition (doped with 8 mol% TiO2) were heat‐treated to produce a series of increasingly SiO2‐enriched Mg‐bearing quartz solid solutions (Qss). The obtained materials were then analysed by X‐ray diffraction: Rietveld structural refinements revealed that Mg‐bearing Qss phases possess trigonal symmetry and a compositionally dependent intermediate structural arrangement between those of low and high quartz. High‐temperature diffraction measurements were performed up to 700 °C to characterize the thermal expansion behaviour of the crystals. At SiO2‐rich compositions, a reversible high‐to‐intermediate inversion of the quartz structure is observed, which shifts with increasing stuffing to lower temperatures than the conventional 573 °C for pure quartz. Similarities and differences to the better‐established Li‐bearing Qss are discussed in the text.
    Keywords glass-ceramics, magnesium aluminosilicate, quartz inversion, quartz solid solutions, X-ray diffraction
     

2019

  • A. Zandona, B. Rüdinger, O. Hochrein, J. Deubener
    Crystallization sequence within the keatite solid solution – cordierite mixed compositional triangle with TiO2 as nucleating agent
    Journal of Non-Crystalline Solids, Volume 505, 2019, Pages 320-332, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2018.11.012.
    (https://www.sciencedirect.com/science/article/pii/S0022309318306677)

    Abstract
    Sixteen glasses of mixed keatite solid solution – cordierite stoichiometry, with 4 mol% TiO2 as nucleating agent, were produced and ceramized to investigate their crystallization sequence. Employed analytical methods included differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. Differences were identified already during the first ceramization stages: Al2O3/(Al2O3 + SiO2) and Li2O/(Li2O + MgO) ratios were crucial to determine which seed former phases would precipitate and the nucleation efficiency of each glass, reaching its maximum at Mg-free composition. Metastable formation of high quartz solid solution was observed in all samples; this phase was most persistent at Li2O/(Li2O + MgO) ratio equal to 0.33 and high SiO2-enrichment. Its destabilization led to the appearance of keatite solid solution and/or indialite, whose crystallization sequence and final relative amounts, as well as the microstructure of the glass-ceramics, were strongly influenced by the composition of the parent glasses.
    Keywords: Lithium-magnesium aluminosilicate glasses; Crystallization; High quartz solid solution; Keatite solid solution; Cordierite
     
  • A. Zandona, C. Patzig, B. Rüdinger, O. Hochrein, J. Deubener,
    TiO2(B) nanocrystals in Ti-doped lithium aluminosilicate glasses
    Journal of Non-Crystalline Solids: X, Volume 2, 2019, 100025, ISSN 2590-1591
    doi.org/10.1016/j.nocx.2019.100025.
    (https://www.sciencedirect.com/science/article/pii/S259015911930038X)

    Abstract
    Three different compositions of TiO2-doped lithium aluminosilicate glass were annealed and analyzed to investigate their first stages of crystallization. After phase separation had occurred, monoclinic TiO2(B) was invariably observed as the first seed forming phase. Phase identification was confirmed by Raman spectroscopy and transmission electron microscopy, disproving its interpretation as pseudobrookite in previous literature sources. The phase was observed to undergo gradual transformation into anatase with increasing temperature, but its persistence was longer in the Si-richer samples. It disappeared right before the volume crystallization of high quartz solid solution and keatite solid solution.
    Keywords: TiO2(B); Lithium aluminosilicate glass; Titania nucleation; Glass-ceramics
     
  • R. Balzer, H. Behrens, S. Schuth, T. Waurischk, S. Reinsch, R. Müller, M. Fechtelkord, J. Deubener
    The influence of H2O and SiO2 on the structure of silicoborate glasses
    Journal of Non-Crystalline Solids, Volume 519, 2019, 119454, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2019.05.030.
    (https://www.sciencedirect.com/science/article/pii/S0022309319303138)

    Abstract
    To understand the impact of dissolved water on structure and properties, four boron-rich glasses of molar compositions 15-x Na2O x CaO 15 SiO2 70 B2O3 (with x = 0, 7.5, 10) and 10 Na2O 15 SiO2 75 B2O3 were prepared and subsequently hydrated (up to 8 wt% H2O). Density measurements show a non-linear trend upon hydration implying large structural changes in particular at water contents <2 wt%. Near-infrared spectroscopy shows hydroxyl groups are the dominant species in all glasses upon the entire range of water content. Molecular H2O is detectable only at total water contents >2 wt%. 11B MAS NMR spectra show that the abundance of BO4 species is mainly controlled by ratio of (Na2O + CaO)/B2O3 while incorporation of water plays a minor role. Compared to borate glasses, the efficiency of formation of BO4 tetrahedra is favored by crosslinking of the network by SiO4-units. The glass transition temperatures, determined by differential thermal analysis, decreases continuously with water content due to breakage of B-O-B bonds by hydrolysis. However, compared to silicates and aluminosilicates, the effect of dissolved water is less pronounced which can be explained by weaker B-O-B bonds in comparison to Si-O-Si bonds.
    Keywords: Water speciation; Silicoborate glasses; Infrared spectroscopy; NMR spectroscopy; High pressure
     
  • P. Kiefer, R. Balzer, J. Deubener, H. Behrens, T. Waurischk, S. Reinsch, R. Müller
    Density, elastic constants and indentation hardness of hydrous soda-lime-silica glasses
    Journal of Non-Crystalline Solids, Volume 521, 2019, 119480, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2019.119480.
    (https://www.sciencedirect.com/science/article/pii/S0022309319303515)

    Abstract
    The effect of structural water on density, elastic constants and microhardness of water-bearing soda-lime-silica glasses of up to 21.5 mol% total water is studied. It is found that the Poisson ratio and the water content are positively correlated, while density and the elastic moduli decrease with increasing water content. Vickers hardness decreases by approximately 27% from the dry to the most hydrous glass. For water fractions <3 mol%, the dependencies are non-linear reflecting the non-linear change in the concentrations of OH and H2O molecules dissolved, whereas for water fractions >3 mol% linear dependencies are found. To distinguish the effect of structural water and environmental water, indentations were performed in toluene, nitrogen gas and air. Time-dependent softening was evident for testing dry glasses in humid atmospheres as well as for tests of hydrous glasses in dry atmospheres. This indicates that the response times of dissolved water species are effectively equal in both scenarios.
    Keywords: Soda-lime-silica glass; Water content; Microhardness; Elastic constants
     
  • L.C. Briese, S. Selle, C. Patzig, J. Deubener, T. Höche
    Depth-profiling of nickel nanocrystal populations in a borosilicate glass – A combined TEM and XRM study
    Ultramicroscopy, Volume 205, 2019, Pages 39-48, ISSN 0304-3991,
    doi.org/10.1016/j.ultramic.2019.06.004.
    (https://www.sciencedirect.com/science/article/pii/S0304399119301032)

    Abstract
    Populations of nickel nanocrystals in a borosilicate glass were studied by TEM and XRM. It is found that XRM, which is applied for the first time to this type of material, is superior for the precise determination of the depth-dependent number densities and volume fractions of precipitated Ni crystals. Statistical precision is gained by imaging 3D data of up to 60 times larger volumes as compared to the volume of the electron transparent rim that a standard TEM wedge specimen provides. Depth-dependent particle-size distributions of XRM were in agreement with those of TEM as the mean sizes of the Ni crystal populations were considerably larger than the XRM resolution limit.
    Keywords: Transmission electron microscopy; X-ray microscopy; Borosilicate glasses; Nickel nanocrystals; Crystallization kinetics
     
  • T. Welter, U. Marzok, J. Deubener, S. Reinsch, R. Müller
    Hydrogen diffusivity in sodium aluminosilicate glasses
    Journal of Non-Crystalline Solids, Volume 521, 2019, 119502, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2019.119502.
    (https://www.sciencedirect.com/science/article/pii/S0022309319303734)

    Abstract
    Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartz-albite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized). Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4 × 10−12 to 3 × 10−14 m2 s−1 (Qz-Np) and from 4 × 10−13 to 3 × 10−15 m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend.
    Keywords: Hydrogen diffusivity; Aluminosilicate glasses; Ionic porosity
     
  • R. Al-Mukadam, J. Deubener
    Effects of cooling rate and oxygen partial pressure on heterogeneous crystal nucleation of supercooled lithium disilicate melt in PtRh20 containers
    Journal of Non-Crystalline Solids, Volume 524, 2019, 119642, ISSN 0022-3093
    doi.org/10.1016/j.jnoncrysol.2019.119642.
    (http://www.sciencedirect.com/science/article/pii/S0022309319305137)

    Abstract
    Lithium disilicate melt in DSC containers made of platinum rhodium alloy PtRh20 is repetitively supercooled at two different oxygen partial pressures. Using 5 different cooling rates and 332 runs per cooling rate, kinetic data of heterogeneous crystal nucleation are determined with high statistical significance. Two different types of crystallizations are evident. A first at higher supercooling temperature exclusively consists of lithium disilicate crystals and a second at lower supercooling temperature consists of a mix of lithium metasilicate and quartz crystals. Increasing oxygen partial pressure shifts the probabilities of both nucleation types to higher temperatures and shorter times. It is assumed that under oxidizing conditions an increasing oxygen saturation coverage at the surface of the platinum alloy promotes crystal nucleation close to the three-phase boundary between oxidized metal, supercooled melt and furnace atmosphere.
    Keywords: Lithium disilicate glass; Supercooling; Heterogeneous crystal nucleation; Platinum container; Repetitive scanning calorimetry
     
  • M. Rampf, M. Fisch, G. Helsch, J. Deubener, C. Ritzberger, W. Höland, M. Dittmer
    Quartz‐containing glass‐ceramics in the SiO2–Li2O–K2O–MgO–CaO–Al2O3–P2O5 system.
    Int J Appl Glass Sci. 2019; 10: 330– 338.
    doi.org/10.1111/ijag.13095

    Abstract
    Volume crystallization of quartz, triggered by adding P2O5, was investigated in the multicomponent  SiO2–Li2O–K2O–MgO–CaO–Al2O3–P2O5 glass system. Glass-ceramics comprising quartz as the main crystal phase besides lithium disilicate (Li2Si2O5) as a minor crystal phase were produced by controlled crystallization from the parent glass. According to quantitative crystal phase analysis by means of Rietveld refinement the mass fraction of the minor Li2Si2O5 phase decreased with increasing P2O5 content, while the fraction of quartz increased. Scanning electron microscopy revealed lath-like Li2Si2O5 embedded in a matrix of rather globular quartz crystals forming an interlocking microstructure. Well machinable glass-ceramics with a mean biaxial flexural strength of about 300 MPa and a fracture toughness of about 2.0 MPa × m0.5 could be realized. With mean values ≥13.6 × 10−6 K−1 the glass-ceramics coefficient of thermal expansion is close to the one reported for low-quartz crystals. The ease of production based on conventional glass melting and fabrication technology together with the good mechanical, optical, and machining properties enables the application of these materials in prosthodontics.

2018

  • N. Pronina, S. Krüger, H. Bornhöft, J. Deubener, A. Ehrenberg
    Cooling history of a wet-granulated blast furnace slag (GBS)
    Journal of Non-Crystalline Solids, 499 (2018) 344-349
    (https://doi.org/10.1016/j.jnoncrysol.2018.07.054)

    Abstract
    Granulated blast furnace slag (GBS) is a glassy by-product of the steel industry that is formed during quenching of the molten slag after the blast furnace in a water-jet. To elucidate the cooling history of GBS, calorimetric scanning in the glass transition range and viscometric experiments at temperatures above the liquidus were performed. The GBS studied was of industrial origin with a d50 = 700 μm and > 99% glassy. It is found that GBS glass is of high potential energy, showing a fictive temperature that is approx. 160 K higher than the glass transition temperature under standard cooling conditions. Using different viscosity models and the relationship between quench rate and shear viscosity at the fictive temperature it is calculated that GBS was formed at a cooling rate of approx. 2.6 × 105 K s−1 corresponding to a shear viscosity of 105.9 Pa s. Due to the high Tf and high amount of heat that is released during structural relaxation, GBS is assigned to the class of hyperquenched glasses.
    Keywords: Blast furnace slag; Cooling rate; Calcium aluminosilicate glass; Thermal history; Fictive temperature; Hyperquenched glass

     
  • A. Zandona, B. Rüdinger, O. Hochrein, J. Deubener
    Crystallization and SiAl ordering in cordierite glass-ceramics
    Journal of Non-Crystalline Solids 498 (2018) 160-166
    (https://doi.org/10.1016/j.jnoncrysol.2018.06.013)

    Abstract
    Glass samples of cordierite composition Mg2Al4Si5O18, increasingly doped with TiO2 as nucleating agent, were ceramized up to 1300 °C and analyzed to highlight differences in their crystalline evolution. Employed analytical methods included HT-XRD, DSC and Raman spectroscopy. Glass-ceramics displayed a gradual transition to effective bulk crystallization with increasing TiO2-doping, manifested by earlier and sharper formation of MgO-Al2O3-SiO2 solid solutions of high-quartz structure. The further phase transformation into indialite equally appeared to be influenced by TiO2-content and to be closely related to the compositional and structural evolution of the seed formers, Mg-Al-titanate and rutile. Furthermore, the indialite-cordierite ordering process was investigated by computation of the ordering index at various temperatures from XRD and Raman, again revealing marked differences between TiO2-free and TiO2-bearing compositions.
    Keywords: Magnesium aluminosilicate glasses; Crystallization; Glass-ceramics; Cordierite; Si-Al ordering
     
  • J. Deubener, M. Allix, M.J. Davis, A. Duran, T. Höche, T. Honma, T. Komatsu, S. Krüger, I. Mitra, R. Müller, S. Nakane, M.J. Pascual, J.W.P. Schmelzer, E.D. Zanotto, S. Zhou
    Updated definition of glass-ceramics
    Journal of Non-Crystalline Solids (2018)
    (https://doi.org/10.1016/j.jnoncrysol.2018.01.033)

    Abstract
    Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products for consumer and specialized markets. Evolution of novel glass and ceramic processing routes, a plethora of new compositions, and unique exotic nano- and microstructures over the past 60 years led us to review the definition of glass-ceramics. Well-established and emerging processing methods, such as co-firing, additive manufacturing, and laser patterning are analyzed concerning the core requirements of processing glass-ceramics and the performance of the final products. In this communication, we propose a revised, updated definition of glass-ceramics, which reads “Glass-ceramics are inorganic, non-metallic materials prepared by controlled crystallization of glasses via different processing methods. They contain at least one type of functional crystalline phase and a residual glass. The volume fraction crystallized may vary from ppm to almost 100%”.
    Keywords: Glass-ceramics; Crystallization; Processing
     

  • L. Wondraczek, Z. Pan, T. Palenta, A. Erlebach, S. T. Misture, M. Sierka, M. Micoulaut, U. Hoppe, J. Deubener, G. N. Greaves
    Kinetics of Decelerated Melting
    Adv. Sci. 2018, 1700850.
    (https://doi.org/10.1002/advs.201700850)

    Abstract
    Melting presents one of the most prominent phenomena in condensed matter science. Its microscopic understanding, however, is still fragmented, ranging from simplistic theory to the observation of melting point depressions. Here, a multimethod experimental approach is combined with computational simulation to study the microscopic mechanism of melting between these two extremes. Crystalline structures are exploited in which melting occurs into a metastable liquid close to its glass transition temperature. The associated sluggish dynamics concur with real-time observation of homogeneous melting. In-depth information on the structural signature is obtained from various independent spectroscopic and scattering methods, revealing a stepwise nature of the transition before reaching the liquid state. A kinetic model is derived in which the first reaction step is promoted by local instability events, and the second is driven by diffusive mobility. Computational simulation provides further confirmation for the sequential reaction steps and for the details of the associated structural dynamics. The successful quantitative modeling of the low-temperature decelerated melting of zeolite crystals, reconciling homogeneous with heterogeneous processes, should serve as a platform for understanding the inherent instability of other zeolitic structures, as well as the prolific and more complex nanoporous metal-organic frameworks.

  • G. Helsch, J. Deubener, M. Rampf, M. Dittmer, C. Ritzberger
    Crystallization and quartz inversion temperature of sol-gel derived LAS solid solutions
    Journal of Non-Crystalline Solids, 492 (2018) 130-139.
    (https://doi.org/10.1016/j.jnoncrysol.2018.04.031)

    Abstract
    Crystallization and inversion temperature of sol-gel derived high-quartz solid solutions (HQss) of composition LixAlxSi1−xO2 (with 0 ≤ x ≤ 0.2) in the pseudo-binary system SiO2-LiAlO2 (LAS) are studied. Lithium, aluminum and silicon containing precursors are used to prepare a sol to coat seeded silicon wafers with a thin amorphous LAS film. Using lithium disilicate as a seed material, HQss is formed readily at temperatures >700 °C between the nominal compositions 83.3–100 mol% SiO2, whereas using zirconium titanate as seed, HQss crystallization is observed at higher temperatures (>950 °C) and only at the LiAl-rich side of the compositional join. HQss transforms to keatite solid solution and to high-cristobalite when heated above 1000–1100 °C, respectively. The chemical substitution of Si4+ by Al3+ + Li+ lead to an increase in the a0 unit cell parameter. In films of x < 0.193 a reversible transformation of high-to-low quartz solid solution is evident. The quartz inversion temperature Tc decreased linearly with increasing x. The dependence is best described by the equation Tc (°C) = (569 ± 3) − (2.82 ± 0.06)·103x.
     
  • H. Behrens, U. Bauer, S. Reinsch, P. Kiefer, R. Müller, J. Deubener,
    Structural relaxation mechanisms in hydrous sodium borosilicate glasses,
    Journal of Non-Crystalline Solids 497 (2018) 30-39
    (https://doi.org/10.1016/j.jnoncrysol.2018.05.025.)

    Abstract
    Borosilicate glasses (16Na2O–10B2O3–74SiO2, NBS) with water contents up to 22 mol% H2O were prepared to study the effect of water on structural relaxation using DTA, viscometry and internal friction measurements. The results show that the glass transition temperature Tg of DTA and the isokom temperature T12, of viscometry are in excellent agreement, confirming the equivalence of enthalpy and viscous relaxation for NBS glass. Combining Tg data with water speciation data demonstrates that OH groups are mainly responsible for the decrease of Tg with increasing hydration, while molecular water plays only a minor role. Internal friction spectra at 7.125 Hz confirm the decisive influence of water on mechanical relaxation. The temperature range of α-relaxation (glass transition) strongly decreases while two β-relaxation peaks (sub-Tg) progressively appear with increasing water content. A high temperature β-relaxation peak, attributed to the presence of OH groups, shifts from 670 to 450 K as total water content increases from 0.01 to 5 wt%. A low temperature β-relaxation peak, attributed to molecular water, appears at 380 K and 330 K in glasses containing 3 and 5 wt% H2O, respectively. These findings suggest that relaxation mechanism of different hydrous species at low temperature may contribute to fatigue of stressed glasses.
    Keywords: Borosilicate glasses; Water; Relaxation; Internal friction; Glass transition

  • H. Bornhöft, S. Striepe, J. Wendel, J. Deubener
    Reaction kinetics at the glass steel interface during firing of vitreous porcelain enamels
    Email – Mitteilungen des Deutschen Emailverbandes e.V. 66 (2018) 66-70

    Abstract
    The formation of a bonding layer between steel and a cobalt, nickel and copper oxide containing enamel frit is studied. In particular, micro-probe analysis is used to determine the evolution of microstructure and the change in chemical composition of the enamelsteel boundary as a function of the firing conditions. In the initial stage, an over-saturation of ferrous cations in the enamel glass after the dissolution of the initial scale layer is evident, which leads to a redox potential driven precipitation of iron micro alloys close to the enamel-steel boundary. In the ongoing firing process, a deposition and growing of alloy particles on the steel substrate takes place. Iron is alloyed by cobalt, nickel and copper, which are reduced from their ionic state, while parts of the ferrous iron are oxidized to ferric iron to provide electrons for the reduction processes. It is found that the deposition of iron alloy particles at the steel surface is an additive process. It leads to an adhesive highly structured interface that comprises alloyed iron pins into the enamel. Processes at the steel surface which suggest an electrochemical corrosion of the steel by the cations mentioned above were not observed.

2017

  • S. Krüger, J. Deubener,
    Thermal analysis of repetitive single crystallization events in glass-forming liquids at low undercooling,
    Journal of Non-Crystalline Solids, 2017.
    (https://doi.org/10.1016/j.jnoncrysol.2017.12.037)

    Abstract
    Thermal analyses of 284 repetitive single crystallization events were carried out. In particular, the isothermal liquid-to-crystal transformation kinetics of Poisson-distributed and non-Gaussian shaped exothermic DSC signals are calculated individually and by superimposition. It is found that modes of impingement for anisotropic growth, random and regular dispersions fail to accurately predict the growth exponent if a single crystal or a low number of crystals are growing. Non-stationary effects are evident at low and large crystal fractions which diminish when virtual signals of multiple crystallization events are superimposed. The results show that the precise analytic formulation to calculate the degree of transformation relies on an ensemble of crystals growing simultaneously. Where this is not the case, as in glass-forming liquids cooled from above liquidus temperature, the proper approach is to use a time-averaged signal of repetitive crystallization runs.
    Keywords: Crystallization kinetics; Thermal analysis; DSC; Nucleation; Growth; Impingement

     
  • G. Helsch, J. Deubener
    Interface Crystallization of Ceria in Porous Silica Films for Solar Applications
    Crystals 7(3) (2017) 80
    (https://doi:10.3390/cryst7030080)

    Abstract
    Antireflective (AR) coatings with photocatalytic activity for solar cover glasses are extensively investigated at present, mostly in multilayer systems including titania. In this study, bifunctional single coats from porous silica in combination with up to 33 mol % ceria were prepared by sol–gel dip-coating on low-iron soda-lime float glass. After heat treatment for one hour at 350 °C, the coated glasses were characterized. Solar transmittance decreased with increasing ceria content, whereas photocatalytic activity increases. Crystallization of cubic ceria was detected by grazing incidence X-ray diffraction. Chemical depth profiling by secondary neutral mass spectrometry revealed the enrichment of cerium at the coating surface as well as at the interface to the glass substrate. Self-assembled ceria crystallization at the interfaces resulted in a three-layered mesostructure of the coating, which was verified by field-emission scanning electron spectroscopy. Cubic ceria crystals at the interface act as a barrier for the sodium diffusion from the substrate, which prevents the poisoning of the photocatalyst, while those crystals at the surface act as an electron donor for photooxidation processes, both enabling adequate photocatalytic activity. The triple-layer architecture with the sequence of high/low/high refractive index materials allows for optical interference sustaining the AR-function.
    Keywords: AR-coating; porous silica; photocatalytic activity; ceria; interface crystallization
     
  • J. Deubener, M. Montazerian, S. Krüger, O. Peitl, E.D. Zanotto
    Heating rate effects in time-dependent homogeneous nucleation in glasses
    J. Non-Cryst. Solids 474 (2017) 1-8
    (https://doi.org/10.1016/j.jnoncrysol.2017.07.019)

    Abstract
    Nucleation kinetics of glass-ceramics is frequently determined using Tammann's double-stage heat-treatment. This method requires a complex deconvolution of the experimentally observed induction time (tind), i.e. the intercept of the linear part of the crystal number density curve with the nucleation time axis, into two components. In this paper, double-stage heat treatments were performed, with heating rates between the nucleation and development temperatures covering two orders of magnitude, in samples of a homogeneously nucleating glass-forming system, lithium disilicate. Our results show that tind increases with increasing heating rates with cubic root dependence. In accordance with the theory, tind was split into the intrinsic time required to establish a steady-state cluster size distribution, τ (time-lag) at the nucleation temperature and an incubation time (ti), which is a size, heating rate and development temperature (Td) dependent growth time. We demonstrate that the Collins-Kashchiev nucleation model performs poorly if ti is approximated by the time needed to experimentally detect the first crystal. In contrast, the Shneidman approach is consistent with theory. We found that at any given nucleation temperature, ti is a strong function of the heating rate, and is proportional to tind, whereas τ is a constant, as expected.
    Keywords: Homogeneous crystal nucleation; Induction time; Transient nucleation; Heating rate effect; Lithium disilicate; Glass
     
  • M. Krichevskaya, S. Preis, A. Moiseev, N. Pronina, J. Deubener
    Gas-phase photocatalytic oxidation of refractory VOCs mixtures: Through the net of process limitations
    Catalysis Today 280 1 (2017) 93-98
    (https://doi.org/10.1016/j.cattod.2016.03.041)

    Abstract
    Photocatalytic oxidation (PCO) of volatile organic compounds (VOCs) presents an effective means of indoors air treatment. Shortcomings, however, include relatively low oxidation rate, sometimes formation of toxic by-products and catalyst deactivation. These obstacles are to be surmounted via synthesis of active catalytic materials and efficient catalyst regeneration at properly chosen process parameters. The article describes the photocatalytic performance of a novel flame aerosol synthesised nano-structured titania F3 and the method of accelerated photocatalyst activity restoration using small amounts of ozone. The experimental research into PCO abating VOCs in mixtures was undertaken following the performance of F3 compared to the benchmarking commercially available photocatalyst P25. The mixture containing acrylic acid, acrylonitrile and toluene was degraded at F3 and P25 photocatalysts, whereas the mixture of acrylonitrile, styrene and toluene—at P25 with admixtures of ozone; ozone was also used for regeneration of P25. The contact time, VOCs and ozone concentration in mixtures, temperature, and air humidity varied. In the experimental conditions, the novel photocatalyst showed activity substantially surpassing the one of the benchmark: within the experimental conditions, F3, contrary to P25, showed no symptoms of deactivation, emitting only trace amounts of toxic HCN product. The novel photocatalyst thus confirmed its promising efficiency in abatement of VOCs mixtures. Ozone appeared to be effective aid in both PCO of VOCs and the photocatalyst activity restoration dramatically shortening the photocatalyst regeneration time.
    Keywords: Titanium dioxide; Deactivation; Hydrogen cyanide; Ozone; Photocatalyst; Regeneration
     
  • J. Deubener, W. Höland
    Nucleation and Crystallization of Glasses and Glass-Ceramics
    Frontiers in Materials 4 (2017) 14
    (https://www.frontiersin.org/article/10.3389/fmats.2017.00014)

2016

  • S. Reinsch, C. Roessler, U. Bauer, R. Müller, J. Deubener, H. Behrens
    Water, the other network modifier in borate glasses
    J. Non-Cryst. Solids 432 (2016) 208-217.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2015.10.010)

  • A. Christmann, J. Deubener, O. Hochrein, M. Mondeshki
    Batch-to-Melt Conversion Kinetics in Sodium Aluminosilicate Batches Using Different Alumina Raw Materials
    Int. J. Appl. Glass Sci. 7 (2016) 394-404.
    (http://dx.doi.org/10.1111/ijag.12183)

  • S. Striepe, J. Deubener, M. Potuzak, M.M. Smedskjaer, A. Matthias
    Thermal history dependence of indentation induced densification in an aluminosilicate glass
    J. Non-Cryst. Solids 445 (2016) 34-39
    (https://doi.org/10.1016/j.jnoncrysol.2016.04.046)

  • S. Striepe, H. Bornhöft, J. Deubener, J. Wendel
    Microalloy Precipitation at the Glass-Steel Interface Enabling Adherence of Porcelain Enamel
    Int. J. Appl. Ceram. Technol. 13 (2016) 191–199.
    (http://dx.doi.org/10.1111/ijac.12435)

  • H. Bornhöft, S. Striepe, J. Deubener
    Schlußbericht zum IGF-Vorhaben 17346 N (Teil 4)
    Mitt. DEV 64 (2016) 2-6, 11.

  • A. Pönitzsch, M. Nofz, L. Wondraczek, J. Deubener
    Bulk elastic properties, hardness and fatigue of calcium aluminosilicate glasses in the intermediate-silica range
    J. Non-Cryst. Solids 434 (2016) 1-12.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2015.12.002)

  • S. Dultz, H. Behrens, G. Helsch, J. Deubener
    Electrolyte effects on surface chemistry of basaltic glass in the initial stages of dissolution
    Chemical Geology 426 (2016) 71-84.
    (http://dx.doi.org/10.1016/j.chemgeo.2016.01.027)

  • S. Krüger, J. Deubener
    The TTT Curves of the Heterogeneous and Homogeneous Crystallization of Lithium Disilicate – A Stochastic Approach to Crystal Nucleation
    Frontiers in Materials, Volume 3, Article 42 (2016)
    (http://dx.doi.org/10.3389/fmats.2016.00042)

2015

  • U. Bauer, H. Behrens, M. Fechtelkord, S. Reinsch, J. Deubener
    Water- and boron speciation in hydrous soda-lime-borate glasses
    J. Non-Cryst. Solids 423-424 (2015) 58-67.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2015.05.004)

  • S. Krüger, J. Deubener
    Lag time to crystal nucleation of supercooled lithium disilicate melts: A test of the classical nucleation theory
    J. Non-Cryst. Solids 426 (2015) 1-6.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2015.06.023)

  • S. Krüger, J. Deubener
    Heterogeneous surface nucleation of lithium disilicate glass: An isothermal DSC study
    J. Non-Cryst. Solids 417 (2015) 45-51.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2015.03.013)

  • N. Pronina, D. Klauson, A. Moiseev, J. Deubener, M. Krichevskaya
    Titanium dioxide sol–gel-coated expanded clay granules for use in photocatalytic fluidized-bed reactor
    Appl. Catalysis B: Environmental 178 (2015) 117-123.
    (http://dx.doi.org/10.1016/j.apcatb.2014.10.006)

  • S. Striepe, H. Bornhöft, J. Deubener
    Haftung verbessernde Fayalitschicht am Kontakt Email-Stahl in eisenreichen Emails
    Mitt. DEV 63 (2015) 18-25.

  • I. Hasdemir, S. Striepe, J. Deubener, K. Simon
    A 2000-year perspective on indentation crack resistance and brittleness of glass
    J. Non-Cryst. Solids 408 (2015) 51-56.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2014.10.012)

  • N. Rosenkiewitz, J. Schuhmacher, M. Bockmeyer, J. Deubener
    Nitrogen-free sol–gel synthesis of Al-substituted cubic garnet Li7La3Zr2O12 (LLZO)
    J. Power Sources 278 (2015) 104-108.
    (http://dx.doi.org/10.1016/j.jpowsour.2014.12.066)

  • H. Bornhöft, S. Striepe, J. Deubener
    Schlußbericht zum IGF-Vorhaben 17346 N (Teil 1)
    Mitt. DEV 63 (2015) 58-65.

  • H. Bornhöft, S. Striepe, J. Deubener
    Schlußbericht zum IGF-Vorhaben 17346 N (Teil 2)
    Mitt. DEV 63 (2015) 76-82.

  • H. Bornhöft, S. Striepe, J. Deubener
    Schlußbericht zum IGF-Vorhaben 17346 N (Teil 3)
    Mitt. DEV 63 (2015) 90-96.

2014

  • M. Dressler, B. Rüdinger, J. Deubener
    Crystallization kinetics in a lithium alumosilicate glass using SnO2 and ZrO2 additives
    J. Non-Cryst. Solids 389 (2014) 60-65.
    (http://dx.doi.org/10.1016)/j.jnoncrysol.2014.02.008)

  • A. Matthias, N. Raicevic, R. Donfeu Tchana, D. Kip, J. Deubener
    Density dependence of refractive index of nanoparticle-derived titania films on glass
    Thin Solid Films 558 (2014) 86-92.
    (http://dx.doi.org/10.1016/j.tsf.2014.02.078)

  • R. Donfeu Tchana, T. Pfeiffer, B. Rüdinger, J. Deubener
    Spectroscopy study on the nucleation kinetics of ZrTiO4 in a lithium alumosilicate glass
    J. Non-Cryst. Solids 384 (2014), 25-31.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2013.03.006)

  • J. Deubener
    10th International Symposium on Crystallization in Glasses and Liquids (Crystallization 2012), September 23–26, 2012, Goslar, Germany
    J. Non-Cryst. Solids 384 (2014), 1.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2013.11.014)

  • Stochastic nature of the liquid-to-crystal heterogeneous nucleation of supercooled lithium disilicate liquid
    S. Krüger, J. Deubener
    J. Non-Cryst. Solids 388 (2014), 6-9.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2014.01.036)

  • S. Striepe, H. Bornhöft, J. Deubener
    Einfluss der Rauheit von Stahlblechoberflächen auf die Haftung von Grundemails bei reduzierten Kobalt- und Nickel-Anteilen
    Mitt. DEV 62 (2014) 38-44.

  • S. Striepe, H. Bornhöft, J. Deubener
    Mechanismen der Haftung von haftoxid-haltigem Grundemail auf Stahlblech
    Mitt. DEV 62 (2014) 86-93.

2013

  • S. Striepe, J. Deubener, M.M. Smedskjaer, M. Potuzak
    Environmental effects on fatigue of alkaline earth aluminosilicate glass with varying fictive temperature
    J. Non-Cryst. Solids 379 (2013), 161-168

  • S. Striepe, M.M. Smedskjaer, J. Deubener, U. Bauer, H. Behrens, M. Potuzak, R.E. Youngman, J.C. Mauro, Y. Yue
    Elastic and micromechanical properties of isostatically compressed soda–lime–borate glasses
    J. Non-Cryst. Solids 364 (2013), 44-52.
    (doi: 10.1016/j.jnoncrysol.2013.01.009)

  • S. Striepe, M. Potuzak, M. M. Smedskljaer, J. Deubener
    Relaxation kinetics of the mechanical properties of an aluminosilicate glass
    J. Non-Cryst. Solids 362 (2013), 40-46.

  • S. Krüger, J. Deubener, C. Ritzberger, W. Höland
    Nucleation Kinetics of Lithium Metasilicate in ZrO2-Bearing Lithium Disilicate Glasses for Dental Application
    Int. J. Appl. Glass Sci. 4 (2013), 9-19.
    (doi:10.1111/ijag.12011)

  • H. Bornhöft, J. Deubener
    Kobalt- und Nickel-freie Emails
    Mitt. DEV 61 (2013), 33-37.

  • M. Lepke, P. Fielitz, G. Borchardt, G.H. Frischat
    Oxygen-18, aluminium-26 and silicon-30 self diffusion in aluminosilicate glasses.
    Phys. Chem. Glasses: Eur. J. Glass Sci. Technol. B, 54 (2013), 15 - 19.

  • G.H. Frischat
    Libyan Desert Glass - Mystery and Challenge.
    In: How Science Spies on Nature and how Technology Imitates Nature (A.M. Klonkowski, M. Jaskula, eds.), Publication of the Societas Humboldtiana Polonorun, Vol. 11, 2013, Danzig/Polen, S. 11 - 20.

  • I. Hasdemir, S. Striepe, J. Deubener, B. Schmidt
    Micromechanical properties of banded alterations of archaeological glass fragments
    J. Non-Cryst. Solids 376 (2013), 126–132.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2013.05.012)

  • S. Striepe, J. Deubener
    Effect of lithium-to-magnesium ratio in metaphosphate glasses on crack-tip condensation and sub-critical crack growth
    J. Non-Cryst. Solids 375 (2013), 47-54.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2013.04.063)

  • A. Dittmar, H. Bornhöft, J. Deubener
    Coarsening kinetics in demixed lead borate melts
    J. Chem. Phys. 138, 224502 (2013)
    (http://dx.doi.org/10.1063/1.4808162)

  • A. Moiseev, M. Krichevskaya, F. Qi, A.P. Weber, J. Deubener
    Analysis of photocatalytic performance of nanostructured pyrogenic titanium dioxide powders in view of their polydispersity and phase transition: Critical anatase particle size as a factor for suppression of charge recombination
    Chem. Eng. J. 228 (2013), 614-621.
    (http://dx.doi.org/10.1016/j.cej.2013.05.038)

2012

  • S. Striepe, J. Deubener
    Viscosity and kinetic fragility of alkaline earth zinc phosphate glasses
    J. Non-Cryst. Solids 358(12-13) (2012), 1480–1485.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2012.03.031)
  • S. Striepe, N. Da, J. Deubener, L. Wondraczek
    Micromechanical properties of (Na,Zn)-sulfophosphate glasses.
    J. Non-Cryst. Solids 358(6-7) (2012), 1032-1037.
    (http://dx.doi.org/10.1016/j.jnoncrysol.2012.01.045)
  • G. Helsch, J. Deubener
    Compatibility of antireflective coatings on glass for solar applications with photocatalytic properties.
    Solar Energy 86 (3) (2012), 831-836.
    (http://dx.doi.org/10.1016/j.solener.2011.12.010)
     
  • S. Jõks,  D. Klauson, M. Krichevskaya, S. Preis, F. Qi, A. Weber, A. Moiseev, J. Deubener
    Gas-phase photocatalytic activity of nanostructured titanium dioxide from flame aerosol synthesis.
    Applied Catalysis B-Environmental 111 (2012), 1-9.
    (http://dx.doi.org/10.1016/j.apcatb.2011.09.007)
     
  • C. Müller-Fildebrandt, H. Bornhöft, Y. Shen, P. Hellmold, J. Deubener
    Emailhaftung auf Gusseisen, Teil 1: Methodenentwicklung zur Charakterisierung der Haftfähigkeit von Email auf Gusseisensubstraten
    Mitt. DEV 60 (2012), 34-39.
     
  • Y. Shen, C. Müller-Fildebrandt, H. Bornhöft, P. Hellmold, J. Deubener
    Emailhaftung auf Gusseisen, Teil 2: Experimentelle Durchführung und Ergebnisse der Abzugmethode
    Mitt. DEV 60 (2012), 66-72.

2011

  • G.H. Frischat, M. Szurman, T. Pfeiffer
    Role of sulfur and its diffusion in silicate glass melts
    Int. J. Appl. Glass Sci. 2 (2011), 47-51.

  • J. Deubener, M. Holand, W. Holand, N. Janakiraman, V.M. Rheinberger
    Crack tip fracture toughness of base glasses for dental restoration glass-ceramics using crack opening displacements
    J. Mech. Behav. Biomed. Mat. 4 (2011), 1291-1298.

  • L. Backnaes, J. Deubener, H. Behrens, J. Stelling, S.B. Cichy, A. Bartels Diffusion of the (35)S isotope in soda-lime-silica and sodium trisilicate glass melts
    J. Non-Cryst. Solids 357 (2011), 2941-2948.

  • A. Moiseev, F. Qi, J. Deubener, A. Weber
    Photocatalytic activity of nanostructured titanium dioxide from diffusion flame synthesis
    Chemical Engineering Journal 170 (2011), 308-315.

  • J. Deubener, M. Dressler, B. Rüdinger
    An In Situ High-Temperature X-Ray Diffraction Study of Early-Stage Crystallization in Lithium Alumosilicate Glass-Ceramics
    J. Am. Ceram. Soc. 94 (2011), 1421-1426.

  • F. Qi, A. Moiseev, J. Deubener, A. Weber
    Thermostable photocatalytically active TiO2 anatase nanoparticles
    J. Nanoparticle Res. 13 (2011), 1325-1334.

  • A. de Pablos-Martín, N. Hémono, G.C. Mather, S. Bhattacharyya, T. Höche, H. Bornhöft, J. Deubener, F. Muñoz, A. Durán, M.J. Pascual
    Crystallization Kinetics of LaF3 Nanocrystals in an Oxyfluoride Glass
    J. Am. Ceram. Soc. 94 (2011), 2420–2428.

  • L. Backnäs, J. Deubener
    Experimental Studies on Sulfur Solubility in Silicate Melts at Near-Atmospheric Pressure.
    Revs. Mineral. Geochem. 73 (2011), 143 – 165

  • M. Dressler, B. Rüdinger, J. Deubener
    An in-situ high-temperature X-ray diffraction study of early stage crystallization in lithium alumosilicate glass-ceramics.
    J. Am. Ceram. Soc. 94 (2011), 1421 – 1426

  • L. Wondraczek, J. C. Mauro, J. Eckert, U. Kühn, J. Horbach, J. Deubener, T. Rouxel
    Towards Ultrastrong Glasses.
    Adv. Mater. 23 (2011), 4578 – 4586

2010

  • M.M. Smedskjaer, J.C. Mauro, S. Sen, J. Deubener, Y. Yue
    Impact of network topology on cationic diffusion and hardness of borate glass surfaces
    J. Chem. Phys. 133, 154509 (2010)
     
  • G. Helsch, A. Mös, J. Deubener, M. Höland
    Thermal resistance of nanoporous antireflective coatings on silica glass for solar tower receivers
    Solar Energy Materials and Solar Cells 94 (2010) 2191-2196.
     
  • M.M. Smedskjaer, Y. Yue, J. Deubener, S. Mørup
    Impact of cationic diffusion on properties of iron-bearing glass fibres
    Phys. Chem. Glasses - Eur. J. Glass Sci. Technol. Part B 51 (2010) 271-280.
     
  • M.M. Smedskjaer, Y. Yue, J. Deubener, H.P. Gunnlaugsson, S. Mørup
    Modifying glass surfaces via internal diffusion
    J. Non-Cryst. Solids 356 (2010) 290-298.
     
  • M.M. Smedskjaer, Y. Yue, J. Deubener, H. P. Gunnlaugsson,S. Mǿrup
    Modifying glass surfaces via internal diffusion.
    J. Non-Cryst. Solids 356 (2010) 290 – 298.
     
  • R. Santos, L.F. Santos, R.M. Almeidaa, J. Deubener, L. Wondraczek
    Crystallization of niobium germanosilicate glasses
    J. Solid State Chem. 183(2010) 128-135.
     
  • H. Döscher, G. Lilienkamp, P. Iskra, W. Daum, G. Helsch, S. Becker, R. J. Wrobel, H. Weiss, Y. Suchorski
    High-quality ZrO2/Si(001) thin films by a sol-gel process: Preparation and characterization
    J. Appl. Phys. 107, 094103 (2010).
     
  • G.H. Frischat, M. Leschik, G. Heide, H. Behrens, M. Wiedenbeck
    Hydration and cor-rosion of polymerised aluminosilicate glasses.
    Phys. Chem. Glasses: Eur. J. Glass Sci. Technol. B 51 (2010) 107 – 116.
     
  • M. Lepke, P. Fielitz, G. Borchardt, G.H. Frischat, A. Goß, E. Pösl
    Simultaneous alu-minium-26 and oxygen-18 transport in an alumosilicate glass.
    J. Non-Cryst. Solids 356 (2010) 1604 – 1606.
     
  • M. Lepke, P. Fielitz, G. Borchardt, G.H. Frischat, A. Goß, E. Pösl
    Aluminium-26 and oxygen-18 tracer diffusion measurements in an alumosilicate glass: temperature dependence
    Phys. Chem. Glasses: Eur. J. Glass Sci. Technol. B 51 (2010), 266 - 270.

2009

  • M.M. Smedskjaer, J. Deubener Y. Yue
    Inward cationic diffusion and formation of silica-rich surface nanolayer of glass
    Chem. Mat. 21 (2009), 1242-1247.
     
  • M. Eberstein, S. Reinsch, R. Müller, J. Deubener, W.A. Schiller
    Sintering of glass matrix composites with small rigid inclusions
    J. Eur. Ceram. Soc. 29 (2009), 2469-2479.
     
  • M. Smedskjaer, Y. Yue, J. Deubener, H. Gunnlaugsson
    Correlation between Cationic Diffusion and Fragility of Silicate Glasses
    J. Phys. Chem. B 113 (2009), 11194-11200.
     
  • R. Müller, R. Meszaros, B. Peplinski, S. Reinsch, M. Eberstein, W.A. Schiller, J. Deubener
    Dissolution of alumina, shrinkage and crystallization behavior of glass ceramic composites for LTCC
    J. Am. Ceram. Soc. 92 (2009), 1703-1708
     
  • J. Wu, J. Deubener, J. F. Stebbins, L. Grygarova, H. Behrens, L. Wondraczek, Y. Yue
    Structural response of a highly viscous aluminoborosilicate melt to isotropic and anisotropic compression
    J. Chem. Phys. 131 (2009), 104504
     
  • J. Deubener, G. Helsch, A. Moiseeva, H. Bornhöft
    Glasses for solar energy conversion systems
    J. Eur. Ceram. Soc. 29 (2009), 1203–1210.
     
  • J. Deubener, H. Bornhöft, S. Reinsch, R. Müller, J. Lumeau, L.N. Glebova, L.B. Glebov
    Viscosity, relaxation and elastic properties of photo-thermo-refractive glass
    J. Non-Cryst. Solids 355 (2009), 126–131.
     
  • C.C. de Araujo, C. Bischoff, H. Eckert, A. Buksak, G.H. Frischat
    Structural elucida-tion of alkali fluorozirconate glasses using high-resolution solid state NMR.
    Z. Phys. Chem. 223 (2009) 1217 – 1227.
     
  • K. Kanzler, G.H. Frischat, P. Hellmold
    Prinzipien der Herrstellung und Nutzung von Schaumemails
    Mitt. DEV 57 (2009), 42 - 51.

2008

  • R. Müller, S. Reinsch, M. Eberstein, J. Deubener, W.A. Schiller
    Effects of dispersed Al2O3 particles on sintering of LTCC
    Advanced Mat. Res. 39-40 (2008), 375-380.
     
  • C.W. Sinton, A. Crawford, S. Misture, J. Seeger, L. Wondraczek, J. Deubener
    High temperature reactions between soda–lime–silica glass and lithium aluminosilicate glass ceramics
    Glass Technol.: Eur. J. Glass Sci. Technol. A 49 (2008), 133-138.
     
  • E. Apel, J. Deubener, A. Bernard, M. Höland, R. Müller, H. Kappert, V. Rheinberger, W. Höland
    Phenomena and mechanisms of crack propagation in glass ceramics
    J. Mech. Behav. Biomed. Mat. 1 (2008), 313-325.
     
  • J. Deubener, Y.Z. Yue, H. Bornhöft, M. Ya
    Decoupling between birefringence decay, enthalpy relaxation and viscous flow in calcium boroalumosilicate glasses
    Chem. Geol. 356 (2008), 299-305.
     
  • J. Deubener, H. Behrens, R. Müller, S. Zietka, S. Reinsch
    Kinetic fragility of hydrous soda-lime-silica glasses
    J. Non-Cryst. Solids 354 (2008) 4713-4718.
     
  • J. Deubener, Y. Yue, H. Bornhöft, M. Ya
    Decoupling between birefringence decay, enthalpy relaxation and viscous flow in calcium boroalumosilicate glasses
    Chemical Geology, 256 (2008) 299-305.
     
  • M. Ya, J. Deubener, Y. Yue
    Enthalpy and anisotropy relaxation of glass fibers
    J. Am. Ceram. Soc. 91 (2008) 745-752.
     
  • L. Backnäs, J. Stelling, H. Behrens, J. Goettlicher, S. Mangold, O. Verheijen, RGC Beerkens, J. Deubener
    Dissolution mechanisms of tetravalent sulphur in silicate melts: Evidences from sulphur K edge XANES studies on glasses
    J. Am. Ceram. Soc. 91 (2008) 721-727.
     
  • F. de Moraes, W. Müller, G.H. Frischat, R. Müller
    Corrosion and crystallization at the inner surfaces of glass bricks
    J. Non- Cryst. Solids 354 (2008) 284-289.
     
  • B. Heid, G.H. Frischat, P. Hellmold
    Emaillierungen für Edelstähle
    Mitt. DEV 56 (2008), 2 - 11.

2007

  • Y. Yue, L. Wondraczek, H. Behrens, J. Deubener
    Glass transition in an isostatically compressed calcium metaphosphate glasses
    J. Chem. Phys. 126 (2007) 144902
     
  • L.F. Santos, L. Wondraczek, J. Deubener, R.M. Almeida
    Vibrational spectroscopy study of niobium germanosilicate glasses
    J. Non- Cryst. Solids 353 (2007) 1875-1881
     
  • L. Wondraczek, H. Behrens, Y. Yue, J. Deubener, G.W. Scherer
    Relaxation and glass transition in an isostatically compressed diopside glass
    J. Am. Ceram. Soc. 90 (2007) 1556-1561
     
  • F. Vetere, H. Behrens, V. Misiti, G. Ventura, F. Holtz, R. De Rosa, J. Deubener
    The viscosity of shoshonitic melts (Vulcanello Peninsula, Aeolian Islands, Italy): insights on the magma ascent in dikes
    Chem. Geol. 245 (2007) 89 -102
     
  • R. Müller, M. Eberstein, S. Reinsch, J. Deubener, A. Thiel, W. A. Schiller
    Effect of rigid inclusions on sintering of LTCC
    Eur. J. Glass Sci. Technol. B48 (2007) 259-266
     
  • M. Krzyzak, G. H. Frischat, P. Hellmold
    Surface finishing of enamels by sol-gel coating
    J. Sol-Gel Sci. Techn. 41 (2007) 99-102
     
  • P. Del Gaudio, H. Behrens, J. Deubener
    Viscosity and glass transition temperature of hydrous float glass
    J. Non-Cryst. Solids 353 (2007) 223-236
     
  • M. Opyd, G.H. Frischat, M.L. Aigner, D. Köpsel
    Determination of inert gas solubilities in borosilicate glass melts
    Eur. J. Glass Sci. Technol. A 48 (2007) 31 - 34
     
  • H. Behrens, Y. Zhang, M. Leschik, M. Wiedenbeck, G. Heide, G.H. Frischat
    Molecular H2O as carrier for oxygen diffusion in hydrous silicate melts
    Earth Plantet. Sci. Lett., 254 (2007) 69-76
     
  • M. Opyd, G.H. Frischat, M.L. Aigner, D. Köpsel
    Determination of inert gas solubilities in borosilicate glass melts with special reference to nitrogen
    Eur. J. Glass Sci. Technol. A 48 (2007) 130 - 132
     
  • A. Buksak, G. H. Frischat, G. Heide
    Lithium self-diffusion in some heavy metal fluoride glasses
    J. Non-Cryst. Solids 353 (2007) 2447 - 2451
     
  • M. Szurman, G. Heide, G.H. Frischat, T. Pfeiffer
    Sulphur diffusion in silicate glass melts with particular reference to Schott AF45 glass
    Eur. J. Glass Sci. Technol. A48 (2007) 242-246
     
  • G.H. Frischat, A. Buksak, G. Heide, B. Roling
    Transport processes in heavy metal fluoride glasses
    J. Phys. Chem. Solids 68 (2007) 747-752
     
  • S. Zietka, J. Deubener, H. Behrens, R. Müller
    Glass transition and viscosity of hydrated silica glasses.
    Physics and Chemistry of Glasses 48 (2007) (6), 380 – 387

2006

  • Stelling J., Behrens H., Backnäs L., Mangold S., Göttlicher J.
    Diffusivity and speciation of sulphur in simple silicate melts
    Beih. Eur. J. Mineral. 18 (2006) 136
     
  • Stelling J., Behrens H., Deubener J., Mangold S., Göttlicher J.
    Diffusivity, solubility and speciation of sulphur in silicate melts
    Adv. Sci. Techn. 46 (2006) 93-97
     
  • Backnäs L., Deubener J., Stelling J., Behrens H., Beerkens R.G.C., Verheijen O., Mangold S., Göttlicher J.
    XANES studies on sulphur speciation in silicate glasses
    Beih. Eur. J. Mineral. 18 (2006) 13
     
  • L. Wondraczek, J. Deubener, S.T. Misture, R. Knitter
    Crystallization kinetics of lithium orthosilicate glasses
    J. Am. Ceram. Soc. 89 (2006) 1342-1346
     
  • L. Wondraczek, A. Dittmar, C. Oelgardt, F. Celarie, M. Ciccotti, C. Marliere
    Real-time observation of a non-equilibrium liquid condensate confined at tensile crack tips in oxide glasses
    J. Am. Ceram. Soc. 89 (2006) 746-749
     
  • K. Wilm, G. H. Frischat
    Coating and diffusion studies to improve the performance of silica glass crucibles for the preparation of semiconducting silicon single crystals
    Eur. J. Glass Sci. Technol. A 47 (2006) 7 - 14
     
  • H. Li, R. Brow, J. Deubener, J. T. Kohli, Y. Z. Yue
    Inorganic crystalline and amorphous fibers - Science and technology
    J. Am. Ceram. Soc. 89 (2006) 1
     
  • A. Buksak, G. Heide, G. H. Frischat
    Na+-Li+ ion exchange on some heavy metal fluoride glasses
    Eur. J. Glass Sci. Technol. B 47 (2006) 203 - 205
     
  • G. Helsch, M. Krzyzak, G. Heide, G.H. Frischat
    Adherent antireflection coatings on borosilicate glass for solar collectors
    Eur. J. Glass Sci. Technol. A, 47 (2006) 153-156
     
  • B. Heid, G.H. Frischat, P. Hellmold
    Möglichkeiten zur gezielten Entwicklung von Edelstahlemails.
    Mitt. DEV 54 (2006) 96 – 101
     
  • K. Kanzler, G. H. Frischat, P. Hellmold
    Möglichkeiten der Herstellung und Nutzung von Schaumemails
    DEV-Mitt. 54 (2006) 46 - 52

2005

  • L. Wondraczek, J. Deubener, U. Lohse.
    Containerless melting of optical glasses by thermal imaging.
    Glass Sci. Technol. 78C (2005), 54-59
     
  • L. Wondraczek, J. Deubener, H. del Pozo, A. Habeck.
    Interfacial energy in phase-separated glasses from emulsion rheology.
    J. Am. Ceram. Soc. 88 (2005), 1673-1675
     
  • C. Römer-Strehl, A. Gebel, G. H. Frischat
    Bleiglasurtechnologie in Mitteleuropa (1. - 12. Jh. n. Chr.): Eine Untersuchung zur Glasurtechnik und -rezeptur.
    Rei Creatariae Romanae Fautorum Acta 39 (2005) 209-216
     
  • B. Martin, Y. Yue, L. Wondraczek, J. Deubener.
    Mechanically induced excess enthalpy in inorganic glasses.
    Appl. Phys. Lett. 86 (2005), 12, 121917
     
  • K. Wondraczek, L. Wondraczek, J. Deubener, D. Johannsmann.
    Application of a quartz crystal microbalance for property determination and functionality analysis of thin hydrophilic coatings on glass.
    Glass Technol. 46 (2005), 2, 179-182
     
  • M. Wagner, G. H. Frischat, P. Hellmold
    Preparation and properties of model glasses of historic enamels of the Green Vault Museum, Dresden. Glass Sci. Technol. 78 (2005), 29-34
     
  • L. Zhang, H. Eckert, G. Helsch, G. H. Frischat
    Network modification of glasses AlPO4: Sol-gel synthesis and structural characterization of the system Na2O- AlPO4. Z. Phys. Chem. 219 (2005) 71-87
     
  • G. Helsch, L. P. Hoyer, G. H. Frischat, L. Zhang, H. Eckert
    Sol-gel synthesis of Na2O-Al2O3-P2O5 glasses and their characterization by NMR, SNMS, and AFM. J. Sol-Gel Sci. Technol. 33 (2005), 341-345
     
  • B. Radomski, G. H. Frischat, P. Hellmold
    Reasons for corrosion damages of segmential, enamelled tanks. In: Proc. 20th Intern. Enamellers Congr., Instanbul, Turkey 2005, 11-21
     
  • M. Krzyzak, G. H. Frischat, P. Hellmold
    Improvement of enamel surfaces by sol-gel coatings. In: Proc. 20th Intern. Enamellers Congr., Instanbul, Turkey 2005, 211-220
     
  • L. P. Hoyer, G. Helsch, G. H. Frischat, L. Zhang, H. Eckert
    Preparation and characterization of Na2O-Al2O3-B2O3 sol-gel glasses with aluminium lactate and formiate as precursors. Glass Sci. Technol. 78 (2005), 165-172
     
  • U. Hoffmann, G. Heide, G. H. Frischat
    Reactions between sol-gel coatings and some technical glass substrates during consolidation. J. Non-Cryst. Solids 351 (2005), 3562-3569

2004

  • A. Khorsandi, U. Willer, L. Wondraczek, W. Schade.
    In situ and on-line monitoring of CO in an industrial glass furnace by mid-infrared difference-frequency generation laser spectroscopy.
    Appl. Optics 43 (2004), 35, 6481-6486
     
  • J. Deubener, L. Wondraczek.
    Anisotropic alkali silicate glasses by frozen-in strain. In: H. Li (Ed.) Melt chemistry, relaxation and solidification kinetics of glasses. The American Ceramic Society
    Ceram. Transact. 170, (2004), 47-56
     
  • L. Wondraczek, G. Heide, J. Deubener.
    Force-field simulated stability of nanoscopic SiO2 and MgO clusters
    J. Non-cryst. solids, 345 (2004), 738-741
     
  • G.H. Frischat, J.-F. Poggemann, G. Heide.
    Nanostructure and atomic structure of glass seen by atomic force microscopy
    J. Non-cryst. solids, 345 (2004), 197-202
     
  • J. Deubener.
    Configurational entropy and crystal nucleation of silicate glasses.
    Phys. Chem. Glass. 45 (2004) 61.
     
  • M. Leschik, H. Behrens, M. Wiedenbeck, H. Geissler, G. Heide, G. H. Frischat.
    Determination of H2O and D2O contents in rhyolitic glasses using IR spectroscopy, SIMS, KFT and NRA.
    Phys. Chem. Glass. 45 (2004) 238-251.
     
  • B. Karmakar, G. Heide, G. H. Frischat.
    Comparative atomic force and scanning electron microscopic studies disclosing nanocrystallinity in cordierite glass-ceramics: examples of surface modification.
    Indian J. Phys. 78A (2004) 47-51.
     
  • L. Wondraczek, A. Khorsandi, U. Willer, W. Schade, G. Heide, G. H. Frischat.
    Mid-infrared laser absorption spectroscopy for process and emission control in the glass melting industry.
    Part II: Difference frequency based MIR laser-spectrometer for glass melting furnaces.
    Glass Sci. Technol. 77, 3 (2004) 131-136.
     
  • L. Wondraczek, A. Khorsandi, U. Willer, W. Schade, G. Heide, G. H. Frischat.
    Mid-infrared laser absorption spectroscopy for process and emission control in the glass melting industry. Part I: Potentials.
    Glass Sci. Technol. 77, 2 (2004) 68-76.
     
  • L. Wondraczek, A. Khorsandi, U. Willer, G. Heide, W. Schade, G. H. Frischat.
    Mid-infrared laser-tomographic imaging of carbon monoxide in laminar flames by difference frequency generation, Combust.
    Flame, 138 (1-2), (2004) 30-39.
     
  • R.J. Hong, X. Jiang, B. Szyszka, V. Sittinger, S.H. Xu, W. Werner, G. Heide.
    Erratum to "Comparison of the ZnO:Al films deposited in static and dynamic modes by reactive mid-frequency magnetron sputtering" (J. of Crystal Growth, 253 (2003), 1, 117-128)
    J. Crystal Growth, 260 (2004), 3, 606
     
  • M. Kryzyzak, G. H. Frischat, P. Hellmold.
    Erhöhung der chemischen Resistenz von Emailoberflächen durch Sol-Gel- Beschichtung.
    Mitt. DEV 52 (2004), 25-32
     
  • M. Krzyzak, G. H. Frischat, P. Hellmold.
    Verbesserung der Eigenschaften von Emailierungen durch Sol-Gel-Beschichtung. Mitt. DEV 52 (2004), 58-66
     
  • C.Römer-Strehl, A. Gebel, G. H. Frischat, S. Krabath
    Werkstoffwissenschaftliche Untersuchungen an bleiglasierten mittelalterlichen Scherben aus der Töpfereiwüstung bei Bengerode bei Fredelsloh, Ldkr. Northeim. Consilium medii aevi 7 (2004), 77-91
     
  • G. H. Frischat, U. Hoffmann, G. Heide
    Reactions between sol-gel coatings and floatglass substrates during consolidation. In: Scient. Proc. Riga Techn. Univ., Series: Mat. Sci. & Appl. Chem., 2004, 15-21
     
  • G. Helsch, G. H. Frischat
    Scratch resistant coatings. In: Sol-gel technologies for glass producers and users (eds. M. A. Aegerter, M. Mennig, Kluwer Acad. Publ.),Boston, 2004, 217-221

2003

  • A. Jiricka, A. Helebrant, J. Hamackova, G. Heide, G Frischat.
    Corrosion modeling of simple glasses from the systems SiO2-NaO2-CaO and SiO2-Na2O-MgO
    Glastechn. Berichte, 76 (2003), 6, 298-308
     
  • R.J. Hong, X. Jiang, B. Szyszka, V. Sittinger, S.H. Xu, W. Werner, G. Heide.
    Comparison of the ZnO:Al films deposited in static and dynamic modes by reactive mid-frequency magnetron sputtering
    J. Crystal Growth, 253 (2003), 1, 117-128
     
  • R.J. Hong, X. Jiang, B. Szyszka, V. Sittinger, W. Werner, G. Heide.
    Growth behaviours and properties of the ZnO:Al films prepared by reactive mid-frequency magnetron sputtering
    J. Crystal Growth, 249 (2003), 3, 461-469
     
  • G. H. Frischat. D. Moseler, G. Heide.
    Comment on Bloom on float glass by Chengzhu Ma et al.
    Glass Technol. 33 (2003) 205.
     
  • J. Deubener, R. Müller, H. Behrens, G. Heide.
    Water and the glass transition temperature of silicate melts.
    J. Non-cryst. Solids, 330 (2003) 268-273.
     
  • J.-F. Poggemann, G. Heide, G. H. Frischat.
    Direct view of the structure of different glass fracture surfaces by atomic force microscopy.
    J. Non-Cryst. Solids 326 & 327 (2003) 15-20.
     
  • A. Buksak, G. H. Frischat.
    Sodium self-diffusion in some heavy metal fluoride glasses.
    J. Non-Cryst. Solids 326 & 327 (2003) 68-71.
     
  • A. Wolter, G. H. Frischat, E. Olbrich.
    Investigation of granulated blast furnace slag (GBFS) reactivity by SNMS.
    G. Grieve, G. Owens (eds.); Proc. 11th Intern. Congr. Chem. Cement (2003) 1866-1877.
     
  • J. Cheng, W. Liang, J. Hu, Q. Chen, G. H. Frischat.
    Development of a new alkali resistent coating.
    J. Sol-Gel Sci. Technol. 27 (2003) 309-313.
     
  • G. Heide, B. Müller, G. Kloess, D. Moseler, G. H. Frischat.
    Structural classification of natural non-crystalline silicates.
    J. Non-Cryst. Solids 323, 1-3 (2003) 303-313.
     
  • L. Wondraczek, G. P. Gross, G. Heide, G. H. Frischat.
    Abbe numbers and refractive indices of tektites and volcanic glasses.
    J. Non-Cryst. Solids 323, 1-3 (2003) 127-130.
     
  • L. Zhang, J. C. C. Chan, H. Eckert, G. Helsch, L. Hoyer, G. H. Frischat.
    Novel Sol-Gel Synthesis of Sodium Aluminophosphate Glass Based on Aluminum Lactate.
    Chem. Mater., 15 (14) (2003) 2702-2710.
     
  • A. R. Boccaccini, S. Atig, Y. H. Han, G. Helsch.
    Herstellung und Eigenschaften transparenter faserverstärkter Glasmatrix-Verbundwerkstoffe.
    In: H. P. Degischer (Hrsg.), Verbundwerkstoffe, Wiley-VCH, Weinheim (2003) 349-354.
     
  • G. Helsch, J. Günster, G. H. Frischat, K. Helmig, B. Roling, S. Murugavel.
    Preparation, characterisation and properties of textured glass ceramics in the system Li2O-Al2O3-SiO2.
    Phys. Chem. Glasses, 44 (2003) 19-25.
     
  • L. Wondraczek, B. Weidenfeller, G. Heide, G. H. Frischat, G. Ziegmann.
    Simulation of thermally induced stresses in glass-polymer composites.
    Glass Sci. Technol. 76, 3 (2003) 103-109.
     
  • W. Schade, U. Willer, L. Wondraczek.
    Mid-infrared laser sensors for mapping environment and combustions.
    Glass Sci. Technol. 76, C2 (2003) 109-114.
     
  • A.R. Boccaccini, S. Atiq, G. Helsch.
    Optomechanical glass matrix composites.
    Composites science and technology 63 (2003) 779 - 783.

2002

  • U. Hoffmann, G. Heide, G. H. Frischat
    Reactions between sol-gel layers and glass substrates during consolidation.
    Glass Sci. Technol. 75C2 (2002), 306 - 309
     
  • H. J. Gläser
    Low-emissive coatings on the outer surface of heat-insulating glasses - a challenge to the flat glass industry.
    Glass Sci. Technol. 75 (2002), 12 - 19.
     
  • K. Bange, O. Anderson, F. Rauch, P. Lehuédé, E. Rädlein, N. Tadokoro, P. Mazzoldi, V. Rigato, K. Matsumoto, M. Farnworth
    Multi-method characterization of soda-lime glass corrosion. Part 2. Corrosion in humidity.
    Glass Sci. Technol. 75 (2002), 20 - 33.
     
  • R. J. Hong; X. Jiang, V. Sittinger, B. Szyszka, T. Höing, G. Bräuer, G. Heide, G. H. Frischat
    Uniformity in large area ZnO:Al films prepared by reactive midfrequency magnetron sputtering.
    J. Vac. Sci. Technol. A 20 (3), 2002, 900 -905.
     
  • L. Wondraczek, G. Heide, M. Kilo, N. Nedeljkovic, G. Borchardt, R. A. Jackson
    Computer simulation of defect structure in sillimanite and mullites.
    Phys Chem Minerals (2002) 29, 341 - 345.
     
  • E. Rädlein, A. Buksak, G. Heide, H. J. Gläser, G. H. Frischat
    Weathering of tin oxide coated glass with low IR emissivity.
    Glass Sci. Technol. 75 (2002), 125 - 131.
     
  • D. Moseler, G. Heide, G. H. Frischat
    Atomic force microscope study of the topography of float glasses and a model to explain the bloom effect.
    Glass Sci. Technol. 75 (2002), 174 - 183.
     
  • B. Radomski, G. H. Frischat, P. Hellmold
    Ursachen von Korrosionsschäden an segmentierten, emaillierten Großbehältern.
    Mitteil. DEV 50 (2002), 84 - 90
     
  • R. A. Jackson, G. Heide, M.E.G. Valerio
    Computer modelling of the structure, lattice and defect properties of F- and OH-topaz.
    Radiation effects defects solids 157 (2002), 845 - 848
     
  • A. Gebel, C. Römer-Strehl, G. H. Frischat
    Untersuchungen zum Gefüge, zur Zusammensetzung und zur Blei-Isotopie von hoch- und spätmittelalterlichen Bleiglasuren aus Südniedersachsen.
    Nachrichten aus Niedersachsens Urgeschichte 71 (2002), 53 - 75
     
  • M. Wagner, G. H. Frischat, P. Hellmold
    Haftung kunsthistorischer Emails auf Edelmetallegierungen.
    Mitteil. DEV 50 (2002), 94 - 98
     
  • G. H. Frischat
    Structure of glass seen by atomic force microscopy.
    G. Kordas, P. Chrysicopoulou (eds.), Symposium "Structure of glass", Harokopio University, Athens, Greece 2002, 229 - 241
     
  • G. H. Frischat
    Tin ions in float glass cause anomalies.
    C. R. Chimie 5 (2002), 759 - 763

2001

  • G. H. Frischat, G. Heide, B. Müller, R. A. Weeks
    Mystery of the Libyan desert glasses.
    Physics Chem. Glasses 42 (2001), 179 - 183.
     
  • K. Bange, O. Anderson, F. Rauch, P. Lehuédé, E. Rädlein, N. Tadokoro, P. Mazzoldi, V. Rigato, K. Matsumoto, M. Farnworth
    Multi-method characterization of soda-lime glass corrosion. Part 1. Analysis techniques and corrosion in liquid water.
    Glastech. Ber. Glass Sci. Technol. 74 (2001), 127 - 141.
     
  • K. Heide, G. Heide, G. Kloess
    Glass chemistry of tektites.
    Planetary and Space Science 49 (2001), 839 - 844.
     
  • G. H. Frischat, B. Hueber, B. Rahmdohr.
    Chemical stability of ZrF4- and AlF3-based heavy metal fluoride glasses in water.
    J. Non-Cryst. Solids 284 (2001), 105 - 109
     
  • G. H. Frischat, C. Müller-Fildebrandt, D. Moseler, G. Heide.
    On the origin of the tin hump in several float glasses.
    J. Non-Cryst. Solids 283 (2001), 246 - 249
     
  • E. Olbrich, G. H. Frischat.
    Corrosion of granulated glassy blast furnace slags in aqueous solutions.
    Glastech. Ber. Glass Sci. Technol. 74 (2001), 86 - 96
     
  • G. H. Frischat.
    Gas bubbles in glass melts under microgravity.
    Proc. 1st Int. Symp. Micrograv. Res. & Appl. Phys. Sci. & Biotechnol. Sorrento 2000 (ESA SP-454, 2001), 475 - 479.
     
  • J.-F. Poggemann, A. Goß, G. Heide, E.Rädlein,G. H. Frischat.
    Direct view of the structure of a silica glass fracture surface.
    J. Non-Cryst. Solids 281 (2001), 221 - 226
     
  • G. Heide, M. Leschik, G. H. Frischat.
    Pechstein. Teil 1: Ein wasserreich glasig erstarrter, vulkanischer Gesteinstyp?
    Chem. Erde Geochem., 61 (2001), 149 - 175

2000

  • M. Wagner, G. H. Frischat, P. Hellmold
    Email auf Edelmetall: Haftung und mechanische Eigenschaften.
    Restauro Heft 6 (2000), 419-421
     
  • G. H. Frischat
    Zwanzig Jahre Weltraumforschung über Glas.
    In: M. H. Keller, P. R. Sahm (Herausg.): Bilanzsymposium Forschung unter Weltraumbedingungen, Norderney 1998, Wissenschaftliche Projektführung RWTH Aachen, 2000, 317 - 321.
     
  • B. Radomski, G. H. Frischat, P. Hellmold
    Korrosion von Emails durch gas- und dampfförmige Komponenten und Kondensate.
    Mitteil. DEV 48 (2000), 93 - 101.
     
  • G. H. Frischat
    Diffusion in glasses and glass melts.
    In: Mass and Charge Transport in Inorganic Materials: Fundamentals to Devices. P. Vincenzini, V. Buscaglia (Eds.), Techna Srl, I-48018 Faenza, 2000, 319 - 328.
     
  • G. Alper, C. Römer-Strehl, A. K. Schuster
    Die Keramik der mittelalterlichen Bergbau- und Hüttensiedlung am Johanneser Kurhaus bei Clausthal-Zellerfeld - Untersuchungen zur Herkunft und Technologie, insbesondere der glasierten Irdenware.
    Ber. Denkmalpflege Nieders. 20 (2000), Nr. 4, 179 - 188.
     
  • G. H. Frischat, C. Müller-Fildebrandt, S. Priller.
    In-depht analysis of a water corroded alkaline earth-rich glass fiber.
    In: Appl Mineralogy, Rammlmair at al. (eds), Balkema, Rotterdam, 2000, 765 - 767
     
  • G. Heide, C. Müller-Fildebrandt, D. Moseler, G. H. Frischat, W. Meisel, A. Maldener, A. Zouine-Thimm, F. Rauch).
    Tin in float glass: A diffusion-reaction model based on surface analysis explains the tin hump.
    Glastech. Ber. Glass Sci. Technol. 73 C2 (2000), 321- 330
     
  • M. Weisz, G. Helsch, G. H. Frischat, K. Helming.
    Textures in glass ceramics of the system Li2O-Al2O3-SiO2.
    Glastech. Ber. Glass Sci. Technol. 73 C1 (2000), 98 - 103
     
  • A. Goß, S. Follner, C. M. Walisch, G. H. Frischat.
    Gas bubbles in glass melts under microgravity. Part 4. An oxygen diffusion experiment.
    Physics Chem. Glasses 41 (2000), 107 - 110
     
  • G. H. Frischat, S. Priller.
    In-depth analysis of the early stage corrosion of technical glass fibers.
    Mikrochim. Acta 133 (2000), 23 - 27
     
  • G. Helsch, E. Rädlein, G. H. Frischat.
    On the origin of the aging process of porous SiO2 antireflection coatings.
    J. Non-Cryst. Solids 265 (2000), 193 - 197
     
  • L. Anselm, G. H. Frischat.
    Early crystallisation stages in a heavy metal fluoride glass prepared under normal and weightless conditions.
    Physics Chem. Glasses 41 (2000); 32 - 37
     
  • H. Kletti, G. Klöß, G. Heide.
    Glaschemische Untersuchungen an massiven Obsidianen von Ikizdere / NO-Türkei
    Terra Nostra, 2 (2000), 58 - 60

1999

  • R. Hauk, G. H. Frischat, K. Ruppert.
    Sol-gel preparation of scratch-resistant Al2O3 coatings on float glass.
    Glastech. Ber. Glass Sci. Technol. 72 (1999), 386 - 392
     
  • J. Liu, E. Rädlein, G. H. Frischat.
    Preparation, nanostructure and properties of indium tin oxide (ITO) films on glass substrates. Part 2. Optimisation of properties.
    Physics Chem. Glasses 40 (1999); 282 - 286
     
  • J. Liu, E. Rädlein, G. H. Frischat.
    Preparation, nanostructure and properties of indium tin oxide (ITO) films on glass substrates. Part 1. Preparation and nanostructure.
    Physics Chem. Glasses 40 (1999), 277 - 281
     
  • R. Mathai, G. H. Frischat.
    Homogeneity of a ZrF4-based glass at the nano-scale.
    J. Non-Cryst. Solids 260 (1999), 175 - 179
     
  • B. Hueber, G. H. Frischat, A. Maldener, O. Dersch, F. Rauch.
    Intitial corrosion stages of a heavy metal fluoride glass in water.
    J. Non-Cryst. Solids 256 & 257 (1999), 130 - 134
     
  • C. Müller-Fildebrandt, S. Priller, G. H. Frischat.
    Analysis of as-prepared and corroded glass fibers by secondary neutral mass spectrometry.
    Glastech. Ber. Glass Sci. Technol. 72 (1999), 227 - 232
     
  • R. P. Heidrich, G. H. Frischat.
    Optimizing the Christiansen-Shelyubskii method and its comparison with industrial control methods for homogeneity determination of glasses.
    Glastech. Ber. Glass Sci. Technol. 72 (1999), 197 - 203
     
  • C. Wünsche, E. Rädlein, G. H. Frischat.
    Morphology of silica and borosilicate glass fracture surfaces by atomic force microscopy.
    Glastech. Ber. Glass Sci. Technol. 72 (1999), 49 - 54

1998

  • S. Priller, G. H. Frischat.
    Early stages of glass fibre corrosion in alkaline solutions.
    Glastech. Ber. Glass Sci. Technol. 71C (1998) 240 - 245
     
  • A. Janke, G. H. Frischat.
    Improved homogeneity of various glasses by gas film levitation.
    Glastech. Ber. Glass Sci. Technol. 71 (1998) 193-198.
     
  • R. Schmitz, G. H. Frischat.
    Depth profiling analysis of lithium and barium disilicate coatings on silica glass.
    Glastech. Ber. Glass Sci. Technol. 71 (1998) 92-96.
     
  • A. Kaufmann, G. H. Frischat.
    High temperature diffusion for the preparation of gradient index lens blanks.
    Solid State Ionics 105 (1998) 297-302.
     
  • S. C. Larson, G. H. Frischat.
    Preparation and properties of R2O-CaO-SiO2-Si3N4 oxynitride glasses and melts.
    Glastech. Ber. Glass Sci. Technol. 71 (1998) 19-24.
     
  • K.H. Holtmann, G. H. Frischat, K. Ruppert
    Mechanism of defect creation on sheet glass by particle impact and its influence on stray light.
    Glastech. Ber. Glass Sci. Technol. 71 (1998), 247 - 255.
     
  • A. Schmidt, G. H. Frischat.
    Atomic force microscopy of early crystallization stages in Li2O.2SiO2 glasses.
    Physics Chem. Glasses 38 (1998) 161-166.
     
  • Y. Du, E. Rädlein, G. H. Frischat.
    Atomic force microscopy study on the crystallization and corrosion of TiO2 coatings on glass by NaOH solutions.
    J. Sol-Gel Sci. Technol. 13 (1998) 763-767.

1997

  • E. Rädlein, G. H. Frischat.
    Atomic force microscopy as a tool to correlate nanostructure to properties of glasses.
    J. Non-Cryst. Solids 222 (1997) 69-82.
     
  • C. Wünsche, E. Rädlein, G. H. Frischat.
    Glass fracture seen with an atomic force microscope.
    Fresenius J. Anal. Chem. 358 (1997) 349-351.
     
  • R. Schmitz, G. H. Frischat, H. Paulus, K.-H. Müller.
    On the quantification of SNMS analyses of silicate glasses and coatings.
    Fresenius J. Anal. Chem. 358 (1997) 42-46.
     
  • L. Anselm, G. H. Frischat.
    Atomic force microscopy of heavy metal flouride glasses.
    J. Non-Cryst. Solids 213 & 214 (1997) 375-380 und 217 (1997) 115-120.
     
  • A. Janke, G. H. Frischat.
    Determination of the critical cooling rate of heavy metal flouride glasses containing nucleating agents.
    J. Non-Cryst. Solids 213 & 214 (1997) 369-374.
     
  • R. Vollmers, E. Rädlein, G. H. Frischat.
    Nanotopography of thin films on glasses as measured with AFM and STM.
    Fundamentals of Glass Sci. Technol. (1997) 23-32.
     
  • H. Kaplan-Diedrich, G. H. Frischat.
    Drawing of oxynitride glass fibers.
    Glastech. Ber. Glass. Sci. Technol. 70 (1997) 109-112.
     
  • G. Mezinskis, E. Rädlein, G. H. Frischat.
    Micro- and nanostructure of Fe2O3-SiO2 sol-gel derived thick coatings.
    J. Sol-Gel Sci. Technol. 8 (1997) 489-492.
     
  • L. Schumacher, G. H. Frischat.
    Laboratory trials to incorporate sulphur in the vitrification of filter ashes from incineration plants and hydrolytic investigation of the melt products.
    Glastech. Ber. Glass Sci. Technol. 70 (1997) 58-63.
     
  • G. H. Frischat, A. Czymai.
    In-depth analysis of glass fibers.
    Mikrochim. Acta 125 (1997) 79-82.

1996

  • E. Larson, L. D. Pye, E. Rädlein, G. H. Frischat, R. A. Weeks.
    Atomic force microscopy investigations on Libyan Desert Glass (LDG) and other silica glasses of different origins.
    Chem. Erde 56 (1996) 423-430.
     
  • G. Buchmayer, E. Rädlein, G. H. Frischat, W. Beier, B. Speit.
    Paramagnetic centers in glasses induced by low earth orbit space radiation.
    J. Non-Cryst. Solids 204 (1996) 253-259.
     
  • K. Engel, G. H. Frischat.
    Textured Li2O-2SiO2glass ceramics.
    J. Non-Cryst. Solids 196 (1996) 339-345.
     
  • S. Priller, G. H. Frischat, L. D. Pye.
    Strengthening of glass through surface crystallization of β-spodumen ss.
    J. Non-Cryst. Solids 196 (1996) 144-149.
     
  • G. Kordas, G. H. Frischat.
    Multifrequency EPR spectroscopy and MNDO calculations for the interpretation of Si-CN-defect centre detected in oxynitride glasses for the first time.
    Phys. Chem. Glasses 37 (1996) 106-110.
     
  • T. von Borstel, G. H. Frischat.
    The influence of residual carbon on the behaviour of superconducting YBa2Cu3O(7-x) derived from sol-gel based precursors.
    cfi/Ber. DKG 73 (1996) 40-43.

1995

  • T. Tenzler, G. H. Frischat.
    Application of the Christiansen-Shelyubskii method to determine homogeneity and refractive index of industrial glasses.
    Glastech. Ber. Glass Sci. Technol. 68 (1995) 381-388.
     
  • R. Ambos, E. Rädlein, G. H. Frischat.
    Surface analysis of sol-gel coatings on glass by secondary neutral mass spectrometry.
    Fresenius J. Anal. Chem. 353 (1995) 614-618.
     
  • M. Hartmann, S. Bintzer-Schmidt, G. H. Frischat.
    Low Tg phosphate glasses with improved water resistance for the coating of fluoride glass fibers.
    Glastech. Ber. Glass Sci. Technol. 68 (1995) 352-359.
     
  • E. Rädlein, R. Ambos, G. H. Frischat.
    Atomic force microscopy of coated glasses.
    Fresenius J. Anal. Chem. 353 (1995) 413-418.
     
  • M. Feike, K. Meise-Gresch, Q. Chen, G. H. Frischat.
    NMR and FTIR characterization of sol-gel derived ternary oxide glasses in the system BaO-TiO2-SiO2.
    Z. Naturforsch. 50a (1995) 837-844.
     
  • A. Czymai, G. H. Frischat.
    A method to determine concentration-distance profiles of corroded glass fibers.
    J. Non-Cryst. Solids 191 (1995) 138-145.
     
  • Y. J. Du, G. H. Frischat.
    Al2O3-TiO2-SiO2 compositions prepared by the alkoxide route. Proc. XVII Intern.
    Congress on Glass, Beijing, V. R. China 1995, Vol. 4, 187-192.
     
  • E. Rädlein, C. Wünsche, G. H. Frischat.
    Atomic force microscopy investigations on vitreous coatings and glass fracture surfaces.
    Proc. XVII Intern. Congress on Glass, Beijing, V. R. China 1995, Vol. 4, 3-8.
     
  • Y. Tang, G. H. Frischat.
    Influence of small additions of Li2O raw materials on glass melting.
    Glastech. Ber. Glass Sci. Technol. 68 (1995) 213-221.
     
  • M. Wendler, H. Krüner, G. H. Frischat.
    Gas bubbles in glass melts under microgravity. Part 3. A further helium diffusion experiment.
    Phys. Chem. Glasses 36 (1995) 109-113.
     
  • K. Engel, G. H. Frischat.
    Texture formation in a glass ceramic of Li2O 2SiO2 composition.
    Textures Microstructures 24 (1995) 155-165.
     
  • H. Kaplan-Diedrich, A. Eckebracht, G. H. Frischat.
    Viscosity and surface tension of oxynitride glass melts.
    J. Am. Ceram. Soc. 78 (1995) 1123-24.
     
  • G. Mezinskis, G. H. Frischat.
    Preparation and optical transmission of BaO-Fe2O3-TiO2-SiO2 gel compositions and coatings.
    In: P. Vincenzini, G. C. Righini (eds.), Advanced Materials in Optics, Elctro-Optics and Communication Technologies, Techna. Srl. (1995) 193-200
     
  • M. Hartmann, K. Högerl, G. F. West, G. H. Frischat.
    Resistant oxide coatings for heavy metal fluoride glasses.
    J. Non-Cryst. Solids 184 (1995) 209-212.
     
  • H. Kaplan-Diedrich, G. H. Frischat.
    Properties of some oxynitride glass fibers.
    J. Non-Cryst. Solids 184 (1995) 133-136.
     
  • R. Ambos, E. Rädlein, G. H. Frischat.
    SNMS and AFM: Combination of two surface sensitive methods for the characterisation of oxide layers and coatings.
    Glastech. Ber. Glass Sci. Technol. 68C1 (1995) 351-359.
     
  • C. Wünsche, E. Rädlein, G. H. Frischat.
    Glass fracture surfaces seen with the atomic force microscope.
    Glastech. Ber. Glass Sci. Technol. 68C1 (1995) 275-282.
     
  • G. Kordas, G. H. Frischat.
    Multifrequency EPR spectroscopy and MNDO calculations for the interpretation of a new nitrogen related paramagnetic defect center detected in oxynitride glasses.
    Glastech. Ber. Glass Sci. Technol. 68C1 (1995) 134-141.

1994

  • G. H. Frischat, M. am Wege, W. Beier, R. A. Weeks.
    Homogeneity of Libyan Desert Glasses.
    J. Non-Cryst. Solids 179 (1994) 309-315.
     
  • Q. Chen, G. H. Frischat, J. Cheng.
    Sol-gel coatings of BaO-TiO2-SiO2compositions.
    J. Sol-Gel Sci. Technol. 2 (1994) 535-538.
     
  • L. Meyer, E. Rädlein, G. H. Frischat.
    Atomare Kraftmikroskopie an synthetischer Dentalkeramik.
    Quintessenz Zahntechn. 20 (1994) 965-972.
     
  • G. H. Frischat.
    Diffusion processes in inorganic glasses and glass melts.
    In: Diffusion in Amorphous Materials., Hrsg. H. Jain, D. Gupta, The Minerals, Metals & Materials Soc., Warrendale, PA, USA (1994) 97-110.
     
  • G. Mezinskis, G. H. Frischat.
    Preparation of SiO2-TiO2-ZrO2 gel compositions by means of a liquid crystal approach.
    Chimica Chronica, New Series 23 (1994) 157-162.
     
  • C. Männicke, G. H. Frischat.
    Crystallization behaviour study of SiO2-Al2O3-MgO glasses containing TiO2 and Na2O.
    Glastech. Ber. Glass Sci. Technol. 67 C (1994) 149-154.
     
  • G. H. Frischat.
    Glass and glass-ceramics in the extreme environment of space.
    J. Non-Cryst. Solids 183 (1994) 92-99.
     
  • E. Rädlein, R. Ambos, G. H. Frischat.
    Hochauflösende Untersuchungsmethoden für die Korrosion an Gläsern.
    In: Korrosion und Verschleiß von keramischen Werkstoffen. R. Telle, P. Quirmbach (Hrsg.), Deutsche Keramische Gesellschaft, 1994, 315-321.

1993

  • M. Meier, G. H. Frischat
    A high temperature centrifuge method to study ion exchange in glass meltsavoiding convective processes.
    Physics Chem. Glasses 34 (1993), 71 - 76.
     
  • B. Steffestun, G. H. Frischat
    Alkali-Resistant Magnesium Aluminosilicate Oxynitride Glasses.
    J. Am. Ceram. Soc. 76 (1993), 699 - 704.
     
  • A. Schmidt - zum Berge, E. Rädlein, G. H. Frischat
    Twin-roller quenching of Bi2Sr2Ca2Cu3O10 melts.
    Glastechn. Ber. 66 (1993), 56 - 60.
     
  • K. Högerl, G. H. Frischat
    Monitoring the glass melting process by using the Christiansen-Shelyubskii Method.
    Ceramic Transactions 29 (1993), 55 - 64.
     
  • P. Frolow, G. H. Frischat
    Influence of different Al2O3-containing batch materials on melting, fining and properties of soda-lime-silica-glass.
    Glastechn. Ber. 66 (1993), 143 - 150.
     
  • E. Rädlein, G. H. Frischat, B. Speit
    Paramagnetic centers in glasses and glass-ceramics induced by simulated space radiation.
    J. Non-Cryst. Solids 162 (1993), 101 - 106.
     
  • A. Becke, R. Reimann, G. H. Frischat, H. L. Ma, C. Blanchetiere, X. H. Zhang, J. Lucas
    Mechanical properties of several TeXAs glasses.
    J. Non-Cryst. Solids 161 (1993), 313 - 315.
     
  • I. Szabo, G. H. Frischat
    Influence of Ag on nucleation and crystallization of fluorozirconate glasses.
    J. Non-Cryst. Solids 161 (1993), 66 - 69.
     
  • G. H. Frischat
    Controlled nucleation and crystallization of fluorozirconate glasses.
    Ceramic Transactions 30 (1993), 233 - 239.
     
  • I. Heinemann, G. H. Frischat
    The sodium transport mechanism in Na2O*2SiO2 glass determined by the Chemla experiment.
    Physics Chem. Glasses 34 (1993), 255 - 260.
     
  • Liang Zhenhua, G. H. Frischat
    The formation and infrared optical properties of some chalcogenide and chalcohalide glasses.
    J. Non-Cryst. Solids 163 (1993), 169 - 176.
     
  • S. Runge, G. H. Frischat
    Interaction between Al2O3-containing droplets and glass melts.
    In: Fundamentals of Glass Sci. Technol., ESG 1993, Venice, Suppl. Rev. Staz. Sper. Vetro 23 (1993), 255 - 260.
     
  • M. Chaissac, J. Claus, G. Borchardt, J. Slowik, G. H. Frischat
    Behaviour of rf sputter deposited SiO2 and Al2O3 diffusion barriers on float glass at 300ºC in air.
    Glastechn. Ber. 66 (1993), 331 - 333.

1992

  • E. Rädlein, G. H. Frischat, B. Speit
    Simulation of the interaction of space radiation with glasses and glass ceramics.
    In: The Physics of Non - Crystalline Solids, ed. by L. D. Pye et al, Taylor & Francis, London (1992), 261 - 265.
     
  • E. Rädlein, G. H. Frischat, B. Speit
    Einsatz von Gläsern und Glaskeramiken im Weltraum.
    Proc. DARA Symp. "Forschung unter Weltraumbedingungen", Aachen, 132 - 137.
     
  • W. - A. Buckermann, W. Müller - Warmuth, G. H. Frischat
    A further 29Si MAS NMR study on binary alkali silicate glasses.
    Glastechn. Ber. 65 (1992), 18 - 21.
     
  • E. de Kever, G. H. Frischat
    Influence of batch moisture and atmosphere on the melting behavior of As2O3 - and Sb2O3 - containing glasses.
    Glastechn. Ber. 65 (1992), 64 - 66.
     
  • B. Speit, E. Rädlein, G. H. Frischat
    Radiation resistant optical glasses.
    Nucl. Instr. Methods Phys. Res. B65 (1992), 384 - 386.
     
  • K. Sebastian, G. H. Frischat
    Silver ion transport in AgI - Ag2O - B2O3 glasses.
    Physics Chem. Glasses 33 (1992), 199 - 203.
     
  • U. Wellbrock, W. Beier, G. H. Frischat
    Preparation of SiO2 - TiO2 - ZrO2 gel glasses and coatings by means of modified alkoxide solutions.
    J. Non - Cryst. Solids 147/148 (1992), 350 - 355.
     
  • L. Meyer, G. H. Frischat
    Kinetics of silver staining in Na2O - CaO - SiO2 glass.
    In: Fundamentals of the Glass Manufacturing Process 1991, Proc. 1st Conf. Europ. Soc. Glass Sci. Technol., 1992, 100 - 103.
     
  • K. Högerl, G. H. Frischat
    Homogenization of glass melts by bubbling.
    Bol. Soc. Esp. Ceram. Vid. 31-C (1992), 179 - 184.
     
  • J. Heinz, W. Pannhorst, G. H. Frischat
    Formation of platinum particles during the production of optical glasses.
    Bol. Soc. Esp. Ceram. Vid. 31-C (1992), 185 - 190.
     
  • E. de Kever, G. H. Frischat
    Melting behavior of glass batches with addition of cadmium - containing compounds.
    Glastechn. Ber. 65 (1992), 325 - 328.
     
  • I. Szabo, J. Molnar, G. H. Frischat
    Effect of Se and Ag on the crystallization of fluorozirconate glasses.
    Bol. Soc. Esp. Ceram. Vid. 31-C (1992), Nr. 2, 334 - 339.
     
  • I. Szabo, G. H. Frischat
    Effect of Se on the crystallization behaviour of ZrF4 - BaF2 - YF3 glass.
    J. Non - Cryst. Solids 140 (1992), 16 - 18.
     
  • E. de Kever, G. H. Frischat
    Influence of batch moisture and atmosphere on the melting behaviour of As2O3 - and Sb2O3 - containing glasses.
    Glastechn. Ber. 65 (1992), 64 - 66.

1991

  • S. - Y. Choi, G. H. Frischat
    Influence of crystallization on some properties of ZrF4 - BaF2 - YF3 - AlF3 glasses.
    J. Non - Cryst. Solids 129 (1991), 133 - 136.
     
  • G. H. Frischat
    Ion exchange processes on glasses.
    In: Surface and Interface Phenomena, Polska Akademia NAUK, Ceramika 39, 1991, p. 23 - 30.
     
  • W. Beier
    Sol - gel coatings on glass.
    In: Surface and Interface Phenomena, Polska Akademia NAUK, Ceramika 39, 1991, p. 31 - 45.
     
  • Th. Richter
    Initial stages of aqueous glass corrosion.
    In: Surface and Interface Phenomena, Polska Akademia NAUK, Ceramika 39, 1991, p. 31 - 46.
     
  • M. Laczka, L. Stoch, I. Lipiarska, W. Beier
    SiO2 and SiO2 - Al2O3 coatings on glass and ceramic materials.
    In: Surface and Interface Phenomena, Polska Akademia NAUK, Ceramika 39, 1991, p. 57 - 63.
     
  • S. Y. Choi, G. H. Frischat
    Controlled nucleation and crystallization in ZrF4 - BaF2 - AlF3 glasses.
    Mat. Sci. Forum 67/68 (1991), 203 - 209.

1990

  • Th. Richter, G. H. Frischat, G. Borchardt, S. Scherrer
    A mathematical model of short time leaching at fracture surfaces.
    J. Non - Cryst. Solids 120 (1990), 117 - 125.
     
  • W. Beier, U. Wellbrock, G. H. Frischat
    Preparation of Li2O - SiO2 gels and glasses by sol - gel methods.
    Glastechn. Ber. 63 (1990), 163 - 171.
     
  • G. Krüner, G. H. Frischat
    Some properties of N - containing lithium borate glasses prepared by different sol - gel methods.
    J. Non - Cryst. Solids 121 (1990), 167 - 170.
     
  • W. Beier, A. A. Göktas, G. H. Frischat
    Kinetics of sol - gel glass formation in the system SiO2 - TiO2 - ZrO2.
    J. Non - Cryst. Solids 121 (1990), 163 - 166.
     
  • Ch. Wies, K. Meise - Gresch, W. Müller - Warmuth, W. Beier, A. A. Göktas, G. H. Frischat
    High resolution solid state nuclear magnetic resonance of the ternary silicate glass SiO2 - TiO2 - ZrO2 prepared by the sol - gel method.
    Physics Chem. Glasses 31 (1990), 138 - 143.
     
  • Th. Richter, G. H. Frischat, G. Borchardt, S. Scherrer
    Initial stages of glass corrosion in water.
    Glastechn. Ber. 63 (1990), 300 - 308.
     
  • W. Beier, Th. v. Borstel, G. H. Frischat
    Preparation of YBa2Cu3O7-x - based superconductors by means of glass - technological methods.
    Glastechn. Ber. 63 (1990), 329 - 335.
     
  • Y. Tang, G. H. Frischat
    Influence of Li2O addition on viscosity and viscosity - dependent glass properties.
    Glastechn. Ber. 63 (1990), 410 - 419.
     
  • M. Meier, V. Braetsch, G. H. Frischat
    Self diffusion in Na2O - Rb2O - SiO2 glass melts as obtained by microgravity experiments.
    J. Am. Ceram. Soc. 73 (1990), 2122 - 2123.
     
  • E. de Kever, G. H. Frischat
    Influence of batch moisture and atmosphere on melting behaviour of lead oxide - containing glass.
    J. Am. Ceram. Soc. 73 (1990), 2165 - 2166.
     
  • I. Heinemann, G. H. Frischat
    Sodium Self - Diffusion in Sodium Disilicate Single Crystals.
    J. Am. Ceram. Soc. 73 (1990), 3712 - 3714.
     
  • W. Hater, W. Müller - Warmuth, B. Steffestun, G. H. Frischat
    Solid - state MAS NMR studies of the structure of magnesium aluminosilicate glasses.
    Glastechn. Ber. 63 (1990), 32 - 36.
     
  • Ch. Wies, K. Meise - Gresch, W. Müller - Warmuth, W. Beier, U. Wellbrock, G. H. Frischat
    29Si MAS NMR studies of sol - gel - derived glasses in the Li2O - SiO2 system.
    J. Non - Cryst. Solids 116 (1990), 161 - 166.

1989

  • W. Beier, G. H. Frischat
    SiO2 - TiO2 - ZrO2 Gel Glasses - Reaction Kinetics and Properties.
    Mat. Res. Soc. Symp. Proc. 155 (1989), 103 - 108.
     
  • W. Beier, A. A. Göktas, G. H. Frischat, Ch. Wies, K. Meise - Gresch, W. Müller - Warmuth
    Kinetics of the formation of SiO2 - TiO2 - ZrO2 gels from alkoxide solutions.
    Physics Chem. Glasses 30 (1989), 69 - 78.
     
  • H. Cremers, B. D. Mosel, W. Müller - Warmuth, G. H. Frischat, V. Braetsch
    121Sb Mössbauer studies of glasses in the system Ge - Sb - Se.
    Physics Chem. Glasses 30 (1989), 79 - 82.
     
  • S. Runge, G. H. Frischat
    Interdiffusion between Al2O3 - containing and Al2O3 - free glass melts.
    Proc. XV Intern. Congress on Glass, Leningrad/USSR 1989, Vol. 2a, 89 - 94.
     
  • W. Beier, U. Horst, G. H. Frischat
    Influence of the salt melt convection on the Ag+/Na+ ion exchange in silicate glasses.
    Proc. XV Intern. Congress on Glass, Leningrad/USSR 1989, Vol. 2b, 88 - 91.
     
  • K. Huntebrinker, B. Wemheuer, M. Grubic, U. Würz
    Apparatus for in situ measurement of light scattering during heat - treatment.
    Rev. Sci. Instrum. 60 (1989), 953 - 954.
     
  • D. Ahlf, G. H. Frischat
    Extension of glass - forming region in a ZrF4 - based system by rapid melt quenching.
    J. Am. Ceram. Soc. 72 (1989), 1506 - 1508.
     
  • M. Laczka, W. Beier, L. Stoch
    Synthesis, structure and certain properties of melted and sol - gel glasses in the SiO2 Al2O3 - SiO2 systems.
    Glastechn. Ber. 62 (1989), 320 - 327.
     
  • W. Hater, W. Müller - Warmuth, G. H. Frischat
    29Si MAS NMR studies of alkali silicate oxinitride glasses.
    Glastechn. Ber. 62 (1989), 328 - 334.
     
  • G. H. Frischat, R. Schwander, W. Beier, R. A. Weeks
    High - temperatuxpansion of Lybian Desert Glasses as compared to thatlasses and natural silicates.
    Cosmochim. Geochim. Acta 53 (1989), 2731 - 2733.
     
  • Y. J. Du, G. H. Frischat, W. Beier
    A mass spectrometer method for the investigation of Li - self - diffusion in mixed alkali glasses.
    J. Non - Cryst. Solids 112 (1989), 399 - 403.
     
  • K. Huntebrinker, U. Würz, G. H. Frischat
    Nucleation and growth of precipitates in demixing glass melts in the system Na2O - CaO - SiO2.
    J. Non - Cryst. Solids 111 (1989), 189 - 198.
     
  • W. Hater, W. Müller - Warmuth, M. Meier, G. H. Frischat
    High - resolution solid - state NMR - studies of mixed - alkali silicate glasses.
    J. Non - Cryst. Solids 113 (1989), 210 - 211.
     
  • W. Beier
    Sol - Gel - und CVD - Beschichtungen auf Glasoberflächen.
    In: Veränderung und Veredelung von Glasoberflächen, HVG - Fortbildungskurs 1989, S. IV/1 - IV/39.
     
  • M. Meier, G. H. Frischat
    Comparison between micro - and macro - g interdiffusion experiments in glass melts.
    Proc. VIIth Europ. Symp. Mat. Fluid Sci. Microgravity, Oxford, UK, Sept.1989, ESA SP - 295 (publ. 1990), 253 - 256.

1988

  • M. Lindig, G. H. Frischat
    Evaporation of antimony trioxide from glass melts.
    J. Am. Ceram.Soc. 71 /1/ (1988), C10.
     
  • W. Beier, A. A. Göktas, G. H. Frischat
    Thin SiO2 - TiO2 - ZrO2 films from alkoxide solutions.
    J. Non - Cryst. Solids 100 (1988), 531 - 537.
     
  • W. Beier, G. Krüner, G. H. Frischat
    Incorporation of nitrogen in Li2O - B2O3 - glasses by conventional melting and via different sol - gel routes.
    Glastechn. Ber. 61 (1988), 91 - 100.
     
  • S. Runge, G. H. Frischat
    Stability of Al2O3 - containing droplets in glass melts.
    J. Non - Cryst. Solids 102 (1988), 157 - 164.
     
  • Ch. Wies, K. Meise - Gresch, W. Müller - Warmuth, W. Beier, A. A. Göktas, G. H. Frischat
    29Si high resolution NMR of the sol - gel chemitry forming SiO2 - TiO2 - ZrO2 glasses from alkoxides.
    Ber. Bunsenges. Phys. Chem. 92 (1988), 689 - 696.
     
  • G. H. Frischat, Th. Richter, G. Borchardt
    Analysis of compositional changes at fracture surfaces of silicate glasses by NPB - SIMS.
    Adv. in Ceramics 22 (1988), 85 - 100.
     
  • V. Braetsch, G. H. Frischat
    Shelyubskii method of studying phase separation in the system Li2O - SiO2.
    J. Am. Ceram.Soc. 71 (1988), C376 - C377.
     
  • G. H. Frischat
    Functional glasses: Fabrication and application.
    New Materials 88 Japan. 2nd Intern. Conf. and Exhib., Osaka/Japan, 140 - 148.
     
  • V. Braetsch, G. H. Frischat
    Influence of microgravity on glass and crystal formation in the system Li2O - SiO2.
    Physics Chem. Glasses 29 (1988), 169 - 172.
     
  • M. Braedt, G. H. Frischat
    Sodium self diffusion in glasses and melts of the system Na2O - Rb2O - SiO2.
    Physics Chem. Glasses 29 (1988), 214 - 218.
     
  • W. Beier, G. H. Frischat
    Libysches Wüstenglas - Eigenschaften und mögliche Entstehung.
    Mitteilungsblatt der TU Clausthal, Heft 66 (1988), 16 - 19.
     
  • W. Beier, G. H. Frischat
    Chemical durability of SiO2 - TiO2 - ZrO2 glass films made from alkoxide solutions.
    Mat. Res. Soc. Symp. Proc. 121 (1988), 817 - 822.
     
  • A. M. Klonkowski, Th. Richter, G. H. Frischat
    The local environment of Cu2+ ions incorporated into glasses by ion exchange.
    J. Non - Cryst. Solids 107 (1988), 11 - 13.
     
  • D. Ahlf, G. H. Frischat
    Preparation and properties of quenched fluoronitride glasses.
    Mat. Sci. Forum 32 / 33 (1988), 149 - 154.
     
  • G. Krüner, G. H. Frischat
    Gasblasen in Glasschmelzen unter Schwerelosigkeit.
    BMFT - DFVLR - Statusseminar "Forschung unter Schwerelosigkeit", Friedrichshafen 1988, DGLR - Bericht, 185 - 189.

1987

  • W. Beier, G. Krüner, G. H. Frischat
    Different ways to incorporate nitrogen in Li2O - B2O3 - glasses.
    Diffusion and Defectz Data Vol. 53 / 54 (1987), 387 - 392.
     
  • G. H. Frischat, D. Ahlf
    Preparation of fluoronitride glasses.
    In: Halide Glasses for Infrared Fiberoptics, R. M. Almeida ( ed. ), NATO ASI Series, Series E: Applied Sciences - No 123.
    Martinus Nijhoff Publ., Dodrecht 1987, 395 - 396.
     
  • Y. J. Du, G. H. Frischat
    Self diffusion and ion exchange in the glass system Li2O - Na2O3 - SiO2.
    Glastechn. Ber. 60 (1987), 64 - 68.
     
  • V. Braetsch, G. H. Frischat
    Influence of microgravity on the homogeneity of glasses.
    Proc. 6th Europ. Symp. Mat. Sci. Microgravity Bordeaux / France 1986, ESA - SP - 256, 259 - 262.
     
  • G. H. Frischat
    Reaktionen zwischen wäßrigen Lösungen und Glasoberflächen.
    In: Physikalische Chemie der Glasoberfläche.
    Friedrich - Schiller - Universität Jena, 1984, 5 - 21.
     
  • Th. Richter, G. H. Frischat
    Glasware loses its lustre in the dishwashing machine.
    German Research, Reports of the DFG 1/87, 4 - 7.
     
  • J. Zarzycki, G. H. Frischat, D. M. Herlach
    Glasses.
    In: H. U. Walter ( ed. ), Fluid Sciences and Materials Science in Space.
    Springer - Verlag Berlin, Heidelberg, New York, London, Paris, Tokyo 1987, 599 - 636.
     
  • G. H. Frischat
    Analysenergebnisse an Glasoberflächen.
    In: S. Lohmeyer ( ed. ), Werkstoff Glas II.
    Expert - Verlag, Ehningen 1987, 189 - 203 / 332 - 333.
     
  • V. Jeschke, G. H. Frischat
    Gas bubbles in glass melts under microgravity. Part 2: Helium diffusion.
    Physics Chem. Glasses 28 (1987), 177 - 182.
     
  • V. Braetsch, G. H. Frischat
    Homogeneity of glasses as prepared under microgravity and 1 - g melting conditions.
    Proc. Sci. Res. German Spacelab Mission D1, Norderney 1986 (publ. 1987), 166 - 171.
     
  • Th. Richter, G. H. Frischat, G. Borchardt, S. Scherrer
    Analyse dünner Korrosionsschichten auf Silikatglasoberflächen.
    Fresenius z. Anal. Chem. (1987), 323 - 326.
     
  • V. Braetsch, G. H. Frischat
    Crystallization and phase separation in the system Li2O - SiO2.
    J. Non - Cryst. Solids 95 / 96 (1987), 457 - 464.
     
  • G. H. Frischat, Th. Richter, G. Borchardt, S. Scherrer
    Surface analysis of a glass leached with stable isotopes.
    Mikrochim. Acta 1987, I, 179 - 192.

1986

  • G. H. Frischat
    Reazioni in sistemi ceramici in condizioni di microgravita.
    La Ceramica 38 (1985), Nr. 5, 11 - 15.
     
  • G. H. Frischat, Th. Richter, G. Borchardt, S. Scherrer
    Initial stages of aqueous glass corrosion.
    Collected Papers XIV Intern. Congr. on Glass (1986), Vol. II, 327 - 332.
     
  • G. H. Frischat
    Load - independent microhardness of glasses.
    In: C. R. Kurkjian ( ed. ), Strength of inorganic glass, NATO Conf. Series, VI: Mat. Sci., 11 (1985), 135 - 145. Plenum Press, New York and London.
     
  • G. H. Frischat
    Mechanical property data.
    In: C. R. Kurkjian ( ed. ), Strength of inorganic glass, NATO Conf. Series, VI: Mat. Sci., 11 (1985), 609 - 620. Plenum Press, New York and London.
     
  • E. Gehrmann, G. H. Frischat
    Influence of batch moisture on melting behaviour of glass.
    J. Am. Ceram. Soc. 69 (1986), C84 - C85.
     
  • J. G. Glabes, R. E. Fern, G. H. Frischat
    Characterization of nitrogen - containing glasses by x - ray photoelectron spectroscopy.
    J. Vac. Sci. Technol. A4 (1986), 1580 - 1584.
     
  • G. H. Frischat
    Ionic transport in glass.
    In: Encyclopedia of Materials Science and Technology, Pergamon Press, Oxford 1986, 2415 - 2418.
     
  • Y. J. Du, G. H. Frischat
    Lithium self diffusion in Li2O - Na2O - Al2O3 - SiO2 glasses.
    Physics Chem. Glasses 27 (1986), 178 - 181.
     
  • V. Braetsch, G. H. Frischat
    Homogeneity of glasses as prepared under microgravity and 1 - g melting conditions.
    Naturwiss. 73 (1986), 368 - 369.
     
  • J. Dietrichs, G. H. Frischat
    Solubility of helium in melts of the metallic glass system Pd - Ni - P and in related systems.
    J. Mat. Sci. 21 (1986), 2535 - 2539.
     
  • W. Beier, A. A. Göktas, G. H. Frischat
    Preparation of SiO2 - TiO2 - ZrO2 glasses from alkoxides.
    J. Am. Ceram. Soc. 69 (1986), C148 - C150.
     
  • M. Lindig, G. H. Frischat
    Evaporation from Pb - and Cd - containing glass melts.
    J. Non - Cryst. Solids 84 (1986), 166 - 173.
     
  • G. H. Frischat, H. Hübenthal
    Entstehung und Verhalten von Gasblasen in Glasschmelzen.
    In: Prozeßkinetik und Prozeßtechnik im Hüttenwesen, Verlag Stahleisen GmbH, Düsseldorf 1986, 357 - 367.
     
  • Th. Richter,G. H. Frischat
    Der Glanzverlust in der Spülmaschine.
    Untersuchungen zum Korrosionsverhalten bei Glas.
    Forschungs - Mitteilungen der DFG 3/86, 4 - 7.
     
  • H. Hübenthal, G. H. Frischat
    Formation and behaviour of nitrogen bubbles in glass melts.
    Glastechn. Ber. 60 (1987), 1 - 10.