TY - CONF A1 - Müller, Ralf T1 - Volatile concentration and mobility measured by VHE-MS N2 - Der Vortrag schildert die Funktionsweise und einige ausgewählte Anwendungsmöglichkeieten der Vakuum-Heißextraktion an der BAM. T2 - Seminar Instrumentelle Analytik, Fakultät III Prozesswissenschaften, Lehrstuhl Keramik TU Berlin CY - TU Berlin, Germany DA - 17.2.2017 KW - Gehalt volatiler Spezies KW - Heißextraktion PY - 2017 AN - OPUS4-44212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Sintering and foaming of barium silicate glass powders N2 - The manufacture of sintered glasses and glass-ceramics, glass Matrix composites and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling scenarios. Sintering was measured by means of heating microscopy backed up by XPD, DTA, Vacuum Hot Extraction (VHE) and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling environment significantly affected foaming. The strength of this effect increased in the order Ar >> N2 < air < CO2. Conformingly, VHE studies revealed that the pores of aerated samples predominantly encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl. T2 - 12th Pacific Rim Conference on Ceramic and Glass Technology CY - Waikoloa, Hawaii, USA DA - 21.5.2017 KW - Sintering KW - Gas bubble formation KW - Foaming PY - 2017 AN - OPUS4-44220 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Körner, S. T1 - Dissolution and reprecipitation of silver in sintering silver-glass dispersions N2 - Electric contacts based on silver-glass dispersions are key components in optoelectronic microsystems and control modules for medical, information & communication and energy technology in our networked society. Driven by the complexity of modern production processes and ever shorter time-to-market requirements, the fast and specific development of tailored silver-glass dispersions has become a bottleneck of technology development. Nevertheless, the underlying mechanisms of silver dissolution, transport, and reprecipitation, and the resulting micro structure evolution during firing are poorly understood. The broad literature on the precipitation of colloidal silver particles and the related processes of silver dissolution and diffusion mostly refer to very small volume fractions of silver. Transferring these results to the sintering of glass-containing silver dispersions, is therefore highly questionable. In this case, silver dissolution, electrical contact between silver particles, transport and reprecipitation take place under special conditions. This includes short diffusion lengths (particle size < 10 μm), the presence of three-phase contacts silver - glass - sintering atmosphere, as well as silver reprecipitation at the sintering contacts as the driving force of silver transport. Here, a dynamic balance of the silver concentration can be expected to result from the ratio between silver dissolution and reprecipitation. The aim of the project is to gain basic insight into the mechanisms of dissolution, transport and reprecipitation of silver in sintering silver glass dispersions. In this context, the main focus is on gaining basic knowledge about the dissolution of metallic silver in low melting oxide glasses as the limiting factor of the sintering of silver-glass composites. In particular, we will strive to gain insight into the effect of the oxygen content of the sintering atmosphere, of the oxygen dissolved in the silver particles, of silver oxide on the surface of the silver powder, of the electric contact between the silver particles, as well as the basicity of the glass. Furthermore, we strive for insights into the silver mobility and the silver concentration that can be attained (silver solubility) in oxide glasses with a low melting point. Summing up all these aspects, a closed explanatory model for silver dissolution, transport and reprecipitation during the sintering of glass silver dispersions will be introduced. T2 - DFG Begutachtungskolloquium (PAK 949/1 und PAK 950/1) CY - Bonn, Germany DA - 07.03.2017 KW - Sintering KW - Silver KW - Glass KW - Solubility KW - Reprecipitation PY - 2017 AN - OPUS4-44227 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wisniewski, W. A1 - Thieme, C. A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Groß-Barsnick, S.-M. A1 - Rüssel, C. T1 - Oriented surface nucleation and crystal growth in a 18BaO·22CaO·60SiO2 mol% glass used for SOFC seals N2 - A glass of the composition 37BaO·16CaO·47SiO2 wt% produced on an industrial scale is crystallized at 970 °C for times ranging from 15 min to 2 h. The crystallization at the immediate surface as well as the crystal growth into the bulk are analyzed using scanning electron microscopy (SEM) including energy dispersive X-ray spectroscopy (EDXS) and electron backscatter diffraction (EBSD) as well as X-ray diffraction in the Θ–2Θ setup (XRD). The immediate surface shows the oriented nucleation of walstromite as well as the formation of wollastonite and an unknown phase of the composition BaCaSi3O8. All three phases also grow into the bulk where walstromite ultimately dominates the kinetic selection and grows throughout the bulk due to a lack of bulk nucleation. Walstromite shows systematic orientation changes as well as twinning during growth. A critical analysis of the XRD-patterns acquired from various crystallized samples indicates that their evaluation is problematic and that phases detected by XRD in this system should be verified by another method such as EDXS. KW - Glass KW - Surface nucleation KW - Orientation KW - EBSD PY - 2018 DO - https://doi.org/10.1039/c7ce02008b VL - 20 IS - 6 SP - 787 EP - 795 PB - Royal Society of Chemistry AN - OPUS4-44405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Master curve for viscous crack healing N2 - A novel method to generalize kinetic data of viscous crack healing in glasses is proposed. The method assumes that crack healing progress is proportional to the healing time, t, and indirect proportional to viscosity, n. This way, crack length and crack width data, normalized to the initial crack length and plotted versus t/n, allow to compare crack healing progress for different cracks and healing temperatures in a master curve. Crack healing experiments conducted in this study demonstrate the applicability of this method for a commercial microscope slide glass. KW - Crack healing KW - Glass KW - Master curve KW - Vickers indentation PY - 2018 DO - https://doi.org/10.1016/j.matlet.2017.12.082 SN - 0167-577X SN - 1873-4979 VL - 216 SP - 110 EP - 112 PB - Elsevier AN - OPUS4-44300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Körner, S. T1 - Dissolution and reprecipitation of silver in sintering silver-glass dispersions N2 - Electric contacts based on silver-glass dispersions are key components in optoelectronic microsystems and control modules for medical, information & communication and energy technology in our networked society. Driven by the complexity of modern production processes and ever shorter time-to-market requirements, the fast and specific development of tailored silver-glass dispersions has become a bottleneck of technology development. Nevertheless, the underlying mechanisms of silver dissolution, transport, and reprecipitation, and the resulting micro structure evolution during firing are poorly understood. The broad literature on the precipitation of colloidal silver particles and the related processes of silver dissolution and diffusion mostly refer to very small volume fractions of silver. Transferring these results to the sintering of glass-containing silver dispersions, is therefore highly questionable. In this case, silver dissolution, electrical contact between silver particles, transport and reprecipitation take place under special conditions. This includes short diffusion lengths (particle size < 10 μm), the presence of three-phase contacts silver - glass - sintering atmosphere, as well as silver reprecipitation at the sintering contacts as the driving force of silver transport. Here, a dynamic balance of the silver concentration can be expected to result from the ratio between silver dissolution and reprecipitation. The aim of the project is to gain basic insight into the mechanisms of dissolution, transport and reprecipitation of silver in sintering silver glass dispersions. In this context, the main focus is on gaining basic knowledge about the dissolution of metallic silver in low melting oxide glasses as the limiting factor of the sintering of silver-glass composites. In particular, we will strive to gain insight into the effect of the oxygen content of the sintering atmosphere, of the oxygen dissolved in the silver particles, of silver oxide on the surface of the silver powder, of the electric contact between the silver particles, as well as the basicity of the glass. Furthermore, we strive for insights into the silver mobility and the silver concentration that can be attained (silver solubility) in oxide glasses with a low melting point. Summing up all these aspects, a closed explanatory model for silver dissolution, transport and reprecipitation during the sintering of glass silver dispersions will be introduced. T2 - DFG Begutachtungskolloquium (PAK 949/1 und PAK 950/1) CY - Bonn, Germany DA - 07.03.2017 KW - Sintering KW - Silver KW - Glass KW - Solubility KW - Reprecipitation PY - 2017 AN - OPUS4-44228 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Behrens, H. A1 - Deubener, J. T1 - Impact of structure and relaxation on fatigue and micromechanical properties of oxide glasses: the role of volatiles and bonding state N2 - As subcritical crack growth (SCCG) can reduce tensile strength of glasses by many orders of magnitude, the potential for improvement of fatigue behaviour is most intriguing in developing ultra-strong glasses. An essential bottleneck is the basic understanding of the numerous interplaying pressure-, temperature- and water-affected relaxation phenomena at the crack tip and related toughening strategies. Therefore, the present project aims to advance the basic understanding of structural relaxation effects and local properties caused by increased water concentration and tensile stresses at the crack tip as they are a key for structural toughening designs to develop SCCG-free glasses and glass surfaces. Our first studies give clear evidence that glass structure and dynamics is strongly modified upon hydration of glasses. These changes are highly related to the nature of network formers but are affected as well by the counter ions (network modifier). Results of the 1st project part suggest that structural relaxation below glass transition temperature, i.e. overlapping of short-range (beta) and long-range (alpha) interactions can contribute to SCCG in water-free environments and that structurally dissolved water in the glasses can have decisive impact on this effect. In the 2nd project stage specific glasses compositions will be investigated to gain an improved understanding on the relation of sub-Tg relaxation and inert SCCG as well as to shed light to the related effects of dissolved water and its speciation. These glasses cover a broader range of different glass topologies and binding partners, whereby the coupling of alpha and beta relaxations is varied systematically by alkali-, alkaline earth ions and water species concentrations. Preparation of hydrous glasses (up to 8 wt% water) will be performed by high pressure syntheses. Structure will be resolved by NMR, Raman and IR spectroscopy while structural relaxation is accessed in the temperature and frequency domain using dynamic mechanical spectroscopy and ultrasonic damping. We will focus on measurements of inert SCCG (region III) conducting experiments in vacuum and dry gas atmospheres using indentation techniques and stressing of glass specimens in DCB geometry. Experimental data on SCCG will be provided to SPP groups, which deals with fatigue in metallic glasses and vice versa we will test theoretical predictions of ab-initio simulations of partner within SPP 1594 in order to quantify the effect of water on the crack tip. In summa topological factors controlling the subcritical crack growth with respect to water will be identified from which structural toughening designs for highly fatigue resistant-glasses can be derived. N2 - Subkritisches Risswachstum (SCCG) kann die Zugfestigkeit von Glas um viele Größenordnungen erniedrigen. Deshalb birgt die Verbesserung des Ermüdungsverhaltens ein hohes Potential für das topologische Design hochfester Gläser. Ein diesbezüglicher Engpass ist das Verständnis der zahlreichen interagierenden druck-, temperatur- und wasserbeeinflussten Relaxationsphänomene an der Rissspitze und hieraus abgeleitete Verstärkungsstrategien. Ziel des Projekts ist es daher, das grundlegende Verständnis der Effekte, die infolge erhöhter Wasserkonzentrationen und Zugspannungen an der Rissspitze entstehen, zu vertiefen, da sie als ein Schlüssel für künftige strukturelle Designprinzipien zur Entwicklung schadenstoleranter Gläser und Glasoberflächen gelten. Unsere ersten Studien zeigen, dass die Struktur und Dynamik von Gläsern nach einer Hydration stark verändert sind. Diese Modifikationen sind mit der Art der Netzwerkbildner stark verknüpft, aber auch von ihren Gegenionen (Netzwerkwandler) abhängig. Die Ergebnisse des ersten Projektabschnitts legen nahe, dass strukturelle Relaxation unterhalb der Glasübergangstemperatur, d. h. ein Überlappen von kurz-reichweitigen (beta) und lang-reichweitigen (alpha) Wechselwirkungen, zum subkritisches Risswachstum in wasserfreien Umgebungen beitragen kann und, dass strukturell gelöstes Wasser in Gläsern sich entscheidend auf diese Effekt auswirken kann. Im zweiten Projektabschnitt werden daher spezielle Glaszusammensetzungen untersucht, die zu einem besseren Verständnis der Verbindung zwischen sub-Tg Relaxation und SCCG führen aber auch den Einfluss von gelöstem Wasser und dessen Speziation näher beleuchten. Diese Gläser weisen eine großen Breite an verschiedenen Topologien und Bindungspartnern auf, wobei die Kopplung von alpha und beta Relaxation durch Veränderungen in den Gehalten von Alkali-, Erdalkalionen und der Wasserspezies systematisch variiert wird. Die Präparation hydratisierter Gläser (bis zu 8 Ma.%) erfolgt mittels Hochdrucksynthesen. Die Glasstruktur wird durch NMR, Raman und IR Spektroskopie aufgeklärt während die Strukturrelaxation anhand dynamische mechanische Spektroskopie und Ultraschalldämpfung im Temperatur- und Frequenzraum erfasst wird. Im Fokus werden Messungen des inerten subkritischen Risswachstums (Region III) stehen, die Indenter-Experimente im Vakuum und trockenen Gasatmosphären sowie Verspannen von Glasproben in DCB Geometrie beinhalten. Experimentelle SCCG Daten werden Gruppen im Schwerpunktprogramm zur Verfügung stellen, die sich mit Ermüdung in metallischen Gläsern beschäftigen und im Gegenzug werden wir theoretische Vorhersagen aus ab initio Simulationen der Partner im SPP 1594 testen, um den Einfluss von Wasser auf die mechanischen Eigenschaften an der Rissspitze und deren Einfluss auf SCCG zu quantifizieren. In summa werden topologische Faktoren bezüglich Wasser, die SCCG kontrollieren, identifiziert, um daraus Designprinzipien für hoch ermüdungsresistente Gläser abzuleiten. T2 - Kolloquium des DFG-PP 1594 CY - Jena, Germany DA - 17.9.2015 KW - Glass KW - Fatigue PY - 2015 AN - OPUS4-38334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Behrens, H. A1 - Bauer, U. A1 - Reinsch, Stefan A1 - Kiefer, P. A1 - Müller, Ralf A1 - Deubener, J. T1 - Structural relaxation mechanisms in hydrous sodium borosilicate glasses N2 - 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. KW - Borosilicate glass KW - Water KW - Relaxation KW - Internal friction KW - Glass transition PY - 2018 DO - https://doi.org/10.1016/j.jnoncrysol.2018.05.025 VL - 497 SP - 30 EP - 39 PB - Elsevier B.V. AN - OPUS4-45608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Thermal Analysis and Relaxation Phenomena in Oxide Glasses N2 - Wasser beeinflusst empfindlich eine Vielzahl von thermisch aktivierten Relaxationsphänomenen in Gläsern wie die Spannungsrelaxation, das unterkritische Risswachstum, innere Reibung, Viskosität, Sinterverhalten und Kristallisation. Thermische Methoden können dabei wesentliche Beiträge zum Verständnis dieser Phänomene liefern. Der Vortrag gibt einen Überblick über die Möglichkeiten der VakuumHeißExtraktion (VHE) zur Untersuchung des Wassergehalts, des Wasserabgabeverhaltens und der Wassermobilität sowie über den Einfluss des Wassers auf die innere Reibung (DMA). N2 - Dissolved water decisively influences numerous thermally activated relaxation phenomena in glasses like stress relaxation, sub-critical crack growth, internal friction, viscosity, sintering, and crystallization. Thermoanalytical methods can essentially help for better understanding of these phenomena. The lecture introduces the Vacuum Hot Extraction method (VHE) and illustrates its possibilities for measuring water content, degassing and mobility. As another thermoanalytical method, the Dynamic Mechanical Themoanalysis (DMA), allowing to study the effect of dissolved water on the internal friction in glasses, is introduced. T2 - Spring school DFG SPP 1594 CY - Hannover, Germany DA - 06.03.2018 KW - Wasser KW - Silicatglas KW - Relaxationsphänomene KW - Relaxation KW - Thermoanalytical Methods KW - Glass KW - Dissolved water PY - 2018 AN - OPUS4-45668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Wasser in Silicatglas N2 - Der Vortrag gibt einen Überblick über den Stand des Wissens zum strukturellen Einbau von Wasser in Silicat- und Boratgläsern, den Einfluss des gelösten Wassers auf deren Viskosität sowie zu den strukturellen Vorstellungen zum Wassertransport. T2 - 1. Fachsymposium der Glasapparatebauer CY - Munich, Germany DA - 19.04.2018 KW - Wasser KW - Glass KW - Struktur PY - 2018 AN - OPUS4-45669 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kotaka, M. A1 - Honma, T. A1 - Komatsu, T. A1 - Shinozaki, K. A1 - Affatigato, M. A1 - Müller, Ralf T1 - Control of self-powdering phenomenon in ferroelastic β′-Gd2(MoO4)3 crystallization in boro-tellurite glasses N2 - Glasses with compositions of 21Gd2O3-63MoO3-(16-x)B2O3-xTeO2 (mol%) (x= 0, 2, 4, 8) were prepared using a conventional melt quenching technique, and the crystallization behavior of ferroelastic β′-Gd2 MoO4)3 Crystals was examined to clarify the mechanism of self-powdering phenomenon and to design bulk crystallized glasses. It was found that the self-powdering phenomenon appeared significantly during the crystallization at temperatures near the crystallization peak temperature, but the phenomenon is suppressed in the crystallization at temperatures much higher than the glass transition temperature. It was also found that the substitution of TeO2 for B2O3 in the base glasses suppresses the self-powdering phenomenon and consequently bulk crystallized glasses were obtained in the glass with x=8 mol%. The densities at room temperature of the base glasses are d =4.755–4.906 g/cm3, being much higher than the value of d=4.555 g/cm3 for β′-Gd2(MoO4)3 crystal. It is proposed that the stresses in the inside of crystals induced by large density differences (i.e., large molar volume differences) between the glassy phase and crystals might be relaxed effectively in the glasses containing TeO2 with weak TeeO bonds and fragile character. KW - Glass crystallization stress PY - 2018 DO - https://doi.org/10.1016/j.jnoncrysol.2017.12.006 SN - 0022-3093 SN - 1873-4812 VL - 501 SP - 85 EP - 92 PB - Elsevier B.V. AN - OPUS4-46472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Hochtemperatur Laserprofilometrie (HTLP) N2 - Der Vortrag gibt einen Überblick über Funktionsweise und Anwendungsmöglichkeiten der an der BAM entwickelten Messmethode der Hochtemperatur-Laserprofilomtrie T2 - Seminar Instrumentelle Analytik, Fakultät III Prozesswissenschaften, Lehrstuhl Keramik TU Berlin CY - TU Berlin, Germany DA - 26.01.2018 KW - Sinterung KW - Hochtemperatur KW - Formerkennung PY - 2018 AN - OPUS4-46475 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - GlasDigital: Data-driven workflow for accelerated glass development N2 - Glasses stand out by their wide and continuously tunable chemical composition and large variety of unique shaping techniques making them a key component of modern high technologies. Glass development, however, is still often too cost-, time- and energy-intensive. The use of robotic melting systems embedded in an ontology-based digital infrastructure might overcome these problems. As part of the German research initiative MaterialDigital [1], the joint project GlasDigital took first steps in this direction combining all main components required for accelerated data driven glass development. For this purpose, a robotic high throughput glass melting system was equipped with inline sensors for process monitoring, machine learning (ML)-based adaptive algorithms for process monitoring and optimization, novel tools for high throughput glass analysis and ML-based algorithms for glass design, including data mining as well as property and process modelling. The talk gives an overview how these tools are interconnected and illustrates their usability. T2 - 27th International Congress on Glass 2025 CY - Kolkata, India DA - 20.01.2025 KW - Materials digitalisation PY - 2025 AN - OPUS4-63820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weh, Lothar A1 - Müller, Ralf A1 - Moseler, D. A1 - Heide, G. A1 - Frischat, G. T1 - Topographische Untersuchungen von Glasoberflächen mit Vickers-Eindrücken T2 - 74. Glastechnische Tagung CY - Ulm, Deutschland DA - 2000-05-29 PY - 2000 SP - 237 EP - 240 PB - DGG, Dt. Glastechn. Ges. CY - Frankfurt/M. AN - OPUS4-934 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Prado, M. O. A1 - Zanotto, E. D. T1 - Model for sintering polydispersed glass particles N2 - We propose a model to describe the sintering kinetics of polydispersed glass particles, having no adjustable parameter. The model is based on three sintering stages: a pure ‘Frenkel' (F) first step, a mixed ‘Frenkel/Mackenzie–Shuttleworth' stage, and a third, pure ‘Mackenzie–Shuttleworth' (MS) step. The model considers sample shrinkage as the sum of the partial shrinkage of several clusters, each consisting of equally sized particles and each showing independent F or MS behavior. The overall set of clusters mimics the specimen's real particle size distribution. We then introduce the concept of neck forming ability, which allows the formation of necks among particles of different sizes, relaxing the clustering condition. Using experimental physical parameters: particle size distribution, viscosity, surface energy, and the theoretical neck forming ability, the model describes well the sintering kinetics of an alumino-borosilicate glass powder having polydispersed, irregular shaped particles in a variety of temperatures. The sintering kinetics of the real powder is slower, but not far from the calculated kinetics of a monodispersed distribution containing only particles of average size. Thus the model provides a tool for estimating the sintering kinetics of real glass powders, for any size distribution and temperature, thus minimizing the number of laboratory experiments. PY - 2001 DO - https://doi.org/10.1016/S0022-3093(00)00399-9 SN - 0022-3093 VL - 279 IS - 2-3 SP - 169 EP - 178 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tielemann, Christopher A1 - Busch, R. A1 - Reinsch, Stefan A1 - Patzig, C. A1 - Höche, T. A1 - Avramov, I. A1 - Müller, Ralf T1 - Oriented surface nucleation in diopside glass N2 - Es wird die Texturbildung in kristallisierendem Diopsidglas im Zusammenhang mit der Oberflächenbeschaffenheit der unbehandelten Probe untersucht. Zudem wird der diskutiert, dass es sich bei der Texturbildung in Gläsern höchstwahrscheinlich um ein Nukleationsphänomen handelt welches auf die richtungsabhängige Grenzflächenenergie der kristallisierenden Phase zurückzuführen ist. N2 - Oriented surface crystallization on polished diopside glass surfaces has been studied with scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy and laser scanning microscopy. An orientation preference of [001] parallel to the glass surface was detected for separately growing diopside crystals even as small as 700 nm in size. This finding shows that crystal orientation occurs in the outermost surface layer without crystal-crystal interaction and indicates that the crystal orientation is a result of oriented nucleation. Depending on surface preparation, monomodal crystal orientation distributions with [100] perpendicular to the surface or bimodal distributions with [100] and [010] perpendicular to the glass Surface were detected. It was also shown that the degree of crystal orientation increases with decreasing Surface roughness. The observed orientation of diopside crystals could be explained in terms of the interfacial energies of different crystal faces. KW - Surface energy KW - Glass ceramic KW - Glass KW - EBSD KW - Diopsid PY - 2021 UR - https://www.sciencedirect.com/science/article/pii/S002230932100020X DO - https://doi.org/10.1016/j.jnoncrysol.2021.120661 SN - 0022-3093 VL - 562 PB - Elsevier B.V. AN - OPUS4-53073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Rouxel, T. A1 - Behrens, H. A1 - Deubener, J. A1 - Müller, Ralf T1 - Vacuum crack growth in alkali silicate glasses N2 - 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. KW - Silicate glass KW - Brittle fracture KW - Crack growth KW - Calculated intrinsic fracture toughness PY - 2021 DO - https://doi.org/10.1016/j.jnoncrysol.2021.121094 SN - 0022-3093 VL - 572 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-53144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Sintering and Foaming of Silicate Glass Powders N2 - The lecture focuses on the mechanisms of non-desired gas bubble formation and foaming during the sintering of glass powder compacts. It is shown that foaming is driven by carbon gases and that carbonates, encapsulated in micropores or mechaniacally dissolved beneath the glass surface, provide the major foaming source. T2 - Sandanski Workshop Sinter crystallization 27th-29th September 2021 PROJECT “THEORY AND APPLICATIONS OF SINTER-CYSTALLIZATION” DN 19/7 CY - Online meeting DA - 27.10. 2021 KW - Sintering KW - Non-desired foaming PY - 2021 AN - OPUS4-53772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Chen, Y.-F. A1 - Contreras Jaimes, A. T1 - Datengetriebener Workflow für die beschleunigte Entwicklung von Glas (GlasDigital) N2 - Das Projekt GlasDigital wurde im allgemeinen vorgestellt, sowie die einzelnen Zwischenstände der verschiedenen Arbeitspakete aller Projektpartner präsentiert. Die allgemeine Porjektvorstellung ist auf deutsch. Die Zwischenstände der Arbeitsinhalte sind auf englisch. T2 - PMD Vollversammlung CY - Berlin, Germany DA - 03.11.2022 KW - Oxidglas KW - Robotische Glasschmelzanlage KW - ML KW - Ontologie KW - Digitaler Zwilling KW - Bildanalyse PY - 2022 AN - OPUS4-56491 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Weh, Lothar A1 - Reinsch, Stefan T1 - Oberflächenprofile partiell kristallisierter Silikatgläser T2 - 73. Glastechnische Tagung CY - Halle (Saale), Deutschland DA - 1999-05-31 KW - Kristallisation KW - Silikatgläser PY - 1999 SP - 26 EP - 29 CY - Frankfurt/Main AN - OPUS4-819 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Viscous crack healing in soda–lime–magnesium–silicate–ZrO2 glass matrix composites N2 - AbstractThe present study investigates the influence of the crystal volume content on viscous crack healing in glass ceramic glass sealants. To ensure constant microstructure during healing, soda–lime–magnesium silicate glass matrix composites with varied volume fractions of ZrO2 filler particles were used. Crack healing was studied on radial cracks induced by Vickers indentation, which were stepwise annealed to monitor the healing progress by confocal laser scanning microscopy. Confirming previous studies, healing of radial cracks in pure glass was found delayed by global flow phenomena like crack widening and crack edge and tip rounding to minimize the sample surface. With increasing ZrO2 filler content, these global flow phenomena were progressively inhibited whereas local flow phenomena like sharp crack tip healing could still occur. As a result, crack healing was even accelerated by filler particles up to a maximum filler content of 17 vol% whereas crack healing was fully suppressed only at 33 vol% filler content. KW - Crack healing KW - Glass matrix composite KW - Solid oxide fuell cell KW - Vickers identation KW - Viscosity PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607860 DO - https://doi.org/10.1111/jace.20002 SN - 0002-7820 SP - 1 EP - 12 PB - Wiley AN - OPUS4-60786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gogula, Shravya A1 - Bornhöft, H. A1 - Wondraczek, L. A1 - Sierka, M. A1 - Diegeler, A. A1 - Müller, Ralf A1 - Deubener, J. T1 - Optical Real-Time Castability Evaluation for High-Throughput Glass Melting N2 - 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. KW - Optical Real-Time Castability Check KW - Image Analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618659 DO - https://doi.org/10.52825/glass-europe.v2i.1359 VL - 2 SP - 83 EP - 93 AN - OPUS4-61865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ried, Peter A1 - Gaber, Martin A1 - Beyer, Katrin A1 - Müller, Ralf A1 - Kipphardt, Heinrich A1 - Kannengießer, Thomas T1 - Thermo Analytic Investigation of Hydrogen Effusion Behavior - Sensor Evaluation and Calibration N2 - The well established carrier gas analysis (CGA) method was used to test different hydrogen detectors comprising a thermal conductivity detector (TCD) and a metal oxide semiconducting (MOx) sensor. The MOx sensor provides high hydrogen sensitivity and selectivity, whereas the TCD exhibits a much shorter response time and a linear hydrogen concentration dependency. Therefore, the TCD was used for quantitative hydrogen concentration measurements above 50?µmol/mol. The respective calibration was made using N2/H2 gas mixtures. Furthermore, the hydrogen content and degassing behaviour of titanium hydride (TiH2-x) was studied. This material turned out to be a potential candidate for a solid sample calibration. Vacuum hot extraction (VHE) coupled with a mass spectrometer (MS) was then calibrated with TiH2-x as transfer standard. The calibration was applied for the evaluation of the hydrogen content of austenitic steel samples (1.4301) and the comparison of CGA-TCD and VHE-MS. KW - Hydrogen KW - Steel KW - Vacuum hot extraction KW - Carrier gas analysis KW - Titanium hydride KW - Gas calibration PY - 2011 DO - https://doi.org/10.1002/srin.201000237 SN - 1611-3683 SN - 0177-4832 VL - 82 IS - 1 SP - 14 EP - 19 PB - Verl. Stahleisen CY - Düsseldorf AN - OPUS4-23202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heunisch, Andreas A1 - Marzok, Ulrich A1 - Münchow, Marco A1 - Müller, Ralf A1 - Rabe, Torsten T1 - In situ characterization of the sintering behavior of LTCC laminates with embedded cavities by high temperature laser profilometry N2 - Three-dimensionally structured LTCC multilayer with channels and inner cavities are required for numerous applications like microreactors, microfluidic systems or sensors. For the performance of such devices, the dimensional accuracy of the embedded structures is crucial. In the green state, the desired structures can be precisely implemented in the LTCC tapes by laser cutting, punching or milling. Unfortunately, during lamination and sintering, shape integrity of cavities and channels is notably affected by warpage and deformation. To investigate the sintering behavior of structured LTCC laminates, a newly developed High Temperature Laser Profilometer (HTLP) can be used. The HTLP allows 3D in-situ shape detection of flat ceramic samples and tapes all along the sintering process. It is applicable for temperatures up to 1000 °C and sample sizes up to 200 mm × 200 mm × 10 mm. During a measurement, the rotating sample is scanned spirally by a linearly moving laser distance sensor through a slot in the furnace top wall. Distance and position values deliver a 3D surface image of the sample. Current lateral dimensions, which are determined by sintering shrinkage, can be measured continuously. Local deformation and warpage can be visualized time- and temperature-resolved. This new method was used, to analyze the sintering behavior of LTCC multilayer laminates containing large size cavities. These were fabricated out of punched green sheets by low pressure lamination without inserts. Samples with cavities of varying cross sections, as well as cavities with and without connection to the surface were observed. T2 - CICMT 2013 - IMAPS/ACerS 9th International conference and exhibition on ceramic interconnect and ceramic microsystems technologies CY - Orlando, FL, USA DA - 23.04.2013 KW - LTCC multilayer KW - Embedded cavities KW - High temperature laser profilometry KW - Low pressure lamination KW - Micro fluidics PY - 2013 DO - https://doi.org/10.4071/cicmt-tha44 SP - 275 EP - 282 AN - OPUS4-35077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agea Blanco, Boris A1 - Blaess, C. A1 - Reinsch, Stefan A1 - Brauer, D. A1 - Müller, Ralf T1 - Sintering and foaming of barium and calcium silicate glass powders N2 - Sintering and foaming of barium and calcium silicate glass powder compacts have been studied for different powder milling. Sintering was measured by means of heating microscopy backed up by XRD, DTA, Vacuum Hot Extraction (VHE) and electron microscopy. Foaming intensity strongly increased with decreasing glass partiefe size. Although powder compacts were uniaxially pressed and sintered in ambient air, foaming was affected by the milling atmosphere and most intensive for milfing in C02. Conformingly, VHE studies revealed that foaming of fully sintered samples was mainly driven by C02, even for powders milled in technical air, Ar and N2. Prolonged storage of air milled barium silicate glass powders in ambient air before pressing and sintering caused further increase of foaming intensity. These findings indicate that carbonaceous species are preferentially trapped to or close beneath the powder surface during milling and later storage. The temperature range of C02 degassing from fully sintered barium and calcium silicate g/ass powder compacts fits the temperature ranges of decomposition of BaC03 and CaC03 mix-milled with the respective barium and calcium silicate glass powders. T2 - IMAPS/ACerS 11th International CICMT conference and exhibition CY - Dresden, Germany DA - 20.04.2015 KW - Sintering KW - Foaming KW - Silicate glass powders KW - Barium and calcium silicate plass powders KW - Degassing PY - 2015 SN - 978-1510804562 SP - 31 EP - 37 AN - OPUS4-35250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinsch, Stefan A1 - Rössler, C. A1 - Bauer, Ute A1 - Müller, Ralf A1 - Deubener, J. A1 - Behrens, H. T1 - Water, the other network modifier in borate glasses N2 - In the present study we have investigated whether the effect of water on properties of borate glasses resembles that of alkali oxide. Soda-lime-borate glasses with nominal compositions of x Na2O, 10 CaO, (90-x) B2O3 (x = 5, 15 and 25 mol%) were doped with up to 8 wt.% H2O by processing glass powder + distilled water in platinum capsules in an internally heated gas pressure vessel at 1523 K and 500 MPa. The water content of hydrous glasses was determined by Karl-Fischer titration and near-infrared spectroscopy. The glass transition temperature T-g. was derived from DTA and micropenetration experiments for which the effect of water loss at the surface of the hydrous glasses was studied. Heating glass samples at 10 K min(-1) in the DTA resulted in T-g values which are close to T-12 isokom temperatures confirming the equivalence of enthalpy relaxation and viscous relaxation for borate glasses. For all three glass series it is shown that T-g strongly decreases whereas the liquid fragility strongly increases upon the addition of water. These findings reveal that H2O primarily causes breaking of B-O-B bonds rather than supporting 4-fold coordinated boron as it is well-known for alkali oxides in this concentration range. (C) 2015 Elsevier B.V. All rights reserved. KW - Wasserhaltige Gläser KW - Viskosität KW - Boratgläser KW - Thermische Analyse KW - Viscosity KW - Borate glasses KW - Thermal analysis KW - Water-bearing glasses PY - 2016 DO - https://doi.org/10.1016/j.jnoncrysol.2015.10.010 SN - 0022-3093 VL - 432 SP - 208 EP - 217 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-35123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Sintering and Foaming of Barium and Calcium Silicate Glass Powders T2 - IMAPS/ACerS 11th International Conference and Exhibition on Ceramic Interconnect and Ceramic Microsystem Technologies (CICMT 2015) CY - Dresden, Germany DA - 2015-04-20 PY - 2015 AN - OPUS4-35197 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Behrens, H. A1 - Deubener, J. A1 - Müller, Ralf T1 - Impact of structure and relaxation on fatigue and micro-mechanical properties of oxide glasses: the role of volatiles and bonding state T2 - Kolloquium des DFG SPP1594 Ultrastrong Glasses CY - Jena, Germany DA - 2015-09-17 PY - 2015 AN - OPUS4-35203 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Sintering and foaming of barium and calcium silicate glass powders T2 - Crystallization 2015 CY - Nagaoka, Japan DA - 2015-10-11 PY - 2015 AN - OPUS4-35198 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Eberstein, Markus A1 - Müller, Ralf A1 - Schiller, Wolfgang Arno A1 - Schweiger, M. T1 - Lastabhängige Schwindung von Glaspulvern N2 - Glasig-kristalline Sinterwerkstoffe werden für vielfältige Anwendungen eingesetzt. Bei einem hohen Glasanteil ist ein Einfluss geringer Lasten auf das Schwindungsverhalten möglich, so dass es zu Fehlinterpretationen des Schwindungsverhaltens bei gebräuchlichen Horizontaldilatometer kommen kann. T2 - 75. Glasetechnische Tagung CY - Wernigerode, Germany DA - 21.05.2001 KW - Glasig-kristalline Sinterwerkstoffe KW - Schwindungsverhalten KW - Horizontaldilatometer PY - 2001 AN - OPUS4-35786 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaber, Martin A1 - Müller, Ralf A1 - Höland, W. T1 - Degassing phenomena during sintering and crystallization of glass powders N2 - Degassing may cause trouble in manufacture of sintered glass-ceramics via the Formation of bubbles (deteriorate mechanical strength or surface Quality) T2 - 6th Int. Otto Schott Colloquium CY - Jena, Germany DA - 06.09.1998 KW - Bulk diffusion KW - Sintering KW - Crystallization KW - Melting PY - 1998 AN - OPUS4-35785 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marzok, Ulrich A1 - Müller, Ralf A1 - Schadrack, Reinhard A1 - Krauhausen, M. A1 - Reetz, R. T1 - Hochtemperatur-Laserprofilometrie für keramische Proben N2 - Das Hochtemperatur-Laserprofilometer der BAM4 ermöglicht eine 3D-Formerkennung an keramischen Folien oder anderen flachen Objekten während thermischer Behandlungen wie zum Beispiel bei laufenden Entbinderungs- oder Sinterprozessen. Mit dem Lasertriangulationssensor werden das Höhenprofil, die lateralen und axialen Schwindungen und andere charakteristische Maße der Probe wie die Folienbreite und -dicke, Abstände zwischen spezifischen Merkmalen oder Krümmungen bestimmt. Somit können insbesondere auch Deformationen und Verwerfungen der Objekte sowie Schwindungsinhomogenitäten an strukturierten Objekten erkannt und mit dem Herstellungsprozess verknüpft werden. T2 - DKG Jahrestagung 2012 CY - Nuremberg, Germany DA - 05.03.2012 KW - 3D-Formerkennung KW - Lasertriangulationssensor KW - Deformationen KW - Schwindungsinhomogenitäten PY - 2012 AN - OPUS4-35787 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agea Blanco, Boris A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Sintering and foaming of barium silicate glass powder compacts N2 - The manufacture of sintered glasses and glass-ceramics, glass matrix composites, and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling procedures. Sintering was measured by means of heating microscopy backed up by XPD, differential thermal analysis, vacuum hot extraction (VHE), and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling atmosphere significantly affected foaming. The strength of this effect increased in the order Ar ≈ N2 < air < CO2. Conformingly, VHE studies revealed that the pores of foamed samples predominantly encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl. KW - Glass powder KW - Sintering KW - Foaming KW - SOFC PY - 2016 UR - http://journal.frontiersin.org/article/10.3389/fmats.2016.00045/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field=&journalName=Frontiers_in_Materials&id=214488 DO - https://doi.org/10.3389/fmats.2016.00045 SN - 2296-8016 VL - 3 SP - Article 45, 1 EP - 10 AN - OPUS4-38303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Hydrogen permeability of glass measured by VHE-MS powder methods N2 - Glasses are can serve as exceptionally tight hydrogen barriers e.g. used for hydrogen storage in micro glass containers or cover glasses in micro electronic systems. Respective glass development, however, requires precise measurements of minimal hydrogen permeability, PH2. Recent studies showed that PH2 can be measured down to 2 10-21 mol s-1 Pa-1m-1 by means of Vacuum Hot Extraction (VHE) powder methods [1]. In this respect the isothermal gas release from glass powder particles is fitted in terms of classical diffusion models assuming spherical particles of uniform size thus obtaining the hydrogen diffusion coefficient, DH2. PH2 is then given by D H2 × S H2, where hydrogen solubility, SH2, is obtained from VHE studies of glass powders exposed to hydrogen atmosphere for different exposure time and hydrogen pressure. Measurements of minimal values of hydrogen permeability, however, require a careful evaluation and error discussion of this method. Against that background, we modeled hydrogen degassing during heating and subsequent isothermal annealing of glass powder particles of different shape and particle size distribution by means of COMSOL Multiphysics® [2] and verified related effects on DH2 obtained by the VHE powder method. T2 - SGT Centenary Conference, & ESG 2016 CY - Sheffield, UK DA - 4.9.2016 KW - Glass KW - Hydrogen KW - Permeability KW - Storage PY - 2016 AN - OPUS4-38307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Boccaccini, A. R. A1 - Müller, Ralf T1 - Sintering and Crystallization of Fluoride-Containing Bioactive Glass F3 N2 - The fluoride-containing bioactive glass F3 with nominal composition (mol%) 44.8 SiO2 - 2.5 P2O3 - 36.5 CaO - 6.6 Na2O - 6.6 K2O - 3.0 CaF2 is a highly promising candidate for bone replacement applications. Its strong crystallization tendency, however, requires a thorough understanding of the interplay between glass powder particle size, surface crystallization, and sintering. Therefore, this study characterizes the sintering and crystallization of bulk specimens and various particle size fractions by differential thermal-analysis, laser scanning, electron microscopy, X-ray diffraction, and Infrared spectroscopy. Particle size fractions < 56 µm were found to fully densify, while crystals growing from the glass particle surface retard sintering of coarser fractions. Small amounts of a non-stoichiometrically calcium phosphosilicate (Ca14.92(PO4)2.35(SiO4)5.65) occurs as the primary crystal phase followed by combeite (Na4Ca4[Si6O18]) as a temporarily dominating phase. The surface crystallization of both pha­ses was found to be mainly responsible for sinter retardation. During later stages of crystallization, additional phases such as cuspidine (Ca4F2Si2O7) and silicorhenanite (Na2Ca4(PO4)2SiO4) occur, but finally monoclinic wollastonite (CaSiO3) forms as the dominant phase. KW - Bioactive Glass KW - Sintering KW - Crystallization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632482 DO - https://doi.org/10.52825/glass-europe.v3i.2564 SN - 2940-8830 VL - 3 SP - 105 EP - 124 AN - OPUS4-63248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Deubener, J. A1 - Müller, Ralf T1 - Internal friction and energy dissipation during fracture in silicate glasses N2 - To obtain a deeper insight into the nature of energy dissipation during fracture, the internal friction of 13 borosilicate, aluminosilicate, soda-lime, and lead-containing glasses, for which inert crack growth data are known, was measured using dynamic mechanical thermal analysis. For asymmetrically bent glass beams, the loss tangent, tan δ, was determined between 0.2 and 50 Hz at temperatures between 273 K and the glass transition temperature, Tg. It was found that the area under the tan δ vs T·Tg−1 curve correlates with the crack growth exponent, n, in the empirical v = v0·KIn relation between crack growth velocity, v, and stress intensity, KI, which indicates that n correlates with the degree of energy dissipation of sub-Tg relaxation phenomena. KW - Glass KW - Internal friction KW - Crack growth PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631582 DO - https://doi.org/10.1063/5.0255432 SN - 0021-9606 VL - 162 IS - 19 SP - 1 EP - 9 PB - AIP Publishing AN - OPUS4-63158 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pan, Z. A1 - Waurischk, Tina A1 - Duval, A. A1 - Müller, Ralf A1 - Deubener, J. A1 - Krishnan, N. M. A. A1 - Wondraczek, K. A1 - Wondraczek, L. T1 - Precise Real‐Time Measurement of Liquid Viscosity Using Digital Video Data N2 - Quantitative knowledge of liquid viscosity is of fundamental importance in many areas of materials synthesis and processing. However, the determination of viscosity often relies on specialized experimental equipment, offline experimentation, or invasive procedures, in particular when required in extreme conditions such as at high temperature, high pressure, and in confined or corrosive environments. Here, this study proposes and validates a fast and simple method that mimics the intuitive perception of liquid flow within a quantitative framework. For this, this study employs digital video observation to derive quantitative values of the shear viscosity of liquids, with high precision and rapid acquisition rates. The technique involves capturing liquid dynamics after minor mechanical stimulation. Processed imaging data are indexed by similarity and referenced to a digital database generated with a finite element model, from which values of viscosity are obtained in line. The approach is tested on water at room temperature and on a high‐temperature glass melt. Covering a viscosity range of four orders of magnitude, both yield convincing agreement with tabulated reference data at low computational cost. KW - Image analyses KW - Liquids KW - Materials discovery KW - Similarity analyses KW - Viscosities PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634606 DO - https://doi.org/10.1002/aisy.202500297 SN - 2640-4567 SP - 1 EP - 12 PB - Wiley AN - OPUS4-63460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, J. A1 - Allix, M. A1 - Davis, M.J. A1 - Duran, A. A1 - Höche, T. A1 - Honma, T. A1 - Komatsu, T. A1 - Krüger, S. A1 - Mitra, I. A1 - Müller, Ralf A1 - Nakane, S. A1 - Pascual, M.J. A1 - Schmelzer, J.W. A1 - Zanotto, E.D. A1 - Zhou, S. T1 - Updated definition of glass-ceramics N2 - 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%”. KW - Glass-ceramics definition PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464711 DO - https://doi.org/10.1016/j.jnoncrysol.2018.01.033 SN - 0022-3093 SN - 1873-4812 VL - 501 SP - 3 EP - 10 PB - Elsevier B.V. AN - OPUS4-46471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Kiefer, P. A1 - Deubener, J. A1 - Balzer, R. A1 - Behrens, H. T1 - Crack Growth in Hydrous Soda-Lime Silicate Glass N2 - 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 b-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. KW - Internal friction KW - Soda-lime silicate glass KW - Water content KW - Stable crack growth KW - DCB geometry KW - Stress intensity factor PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506829 DO - https://doi.org/10.3389/fmats.2020.00066 VL - 7 SP - Articel 66 AN - OPUS4-50682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiefer, P. A1 - Maiwald, M. A1 - Deubener, J. A1 - Balzer, R. A1 - Behrens, H. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses N2 - 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 (< 3x10-6 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. KW - Indentation fracture toughness KW - Slow crack growth KW - Automated analysis KW - Hydrous glass KW - Vickers indentation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513085 DO - https://doi.org/10.3389/fmats.2020.00268 VL - 7 SP - 268 AN - OPUS4-51308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Welter, T. A1 - Müller, Ralf A1 - Deubener, J. A1 - Marzok, Ulrich A1 - Reinsch, Stefan T1 - Hydrogen Permeation Through Glass N2 - 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 as one 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. KW - Ionic porosity KW - hydrogen storage KW - Glass KW - Permeability KW - Solubility KW - Diffusivity PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513927 DO - https://doi.org/10.3389/fmats.2019.00342 VL - 6 SP - Article 342 AN - OPUS4-51392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heuser, Lina A1 - Nofz, Marianne A1 - Müller, Ralf T1 - Alkali and alkaline earth zinc and lead borate glasses: Sintering and crystallization N2 - Glasses in the systems Me2O-ZnO-B2O3 with Me = Li, Na, K, Rb (MeZB), Na2O-ZnO-CuO-B2O3 (NZCuB), CaO-ZnO-B2O3 (CaZB), and Li2O-PbO-B2O3 (LPbB) as a reference, were studied by differential thermal analysis, dilatometry, rotational viscometry, and heating microscopy. A decrease of viscosity and sintering range was found with decreasing number of fourfold coordinated boron. The viscosity of the alkali zinc borate glasses varies only slightly. LPbB and CaZB stand out by their reduced and increased viscosities, respectively. Sodium, potassium, and calcium zinc borate glasses possess a fragility above 76. All glasses were sintered to full density before crystallization. Mostly binary zinc borate phases govern crystallization. A ternary crystalline phase was detected only in the potassium containing sample. The Weinberg glass stability parameter ranges between 0.07 and 0.12. This is caused by the presence of several crystalline phases and varying melting points of even the same crystalline phase in different glass matrices. KW - Alkali zinc borate glasses KW - Lead borate glasses KW - Viscosity KW - Sintering KW - Crystallization KW - Fragility PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556128 DO - https://doi.org/10.1016/j.nocx.2022.100116 SN - 2590-1591 VL - 15 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-55612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Sintering and foaming of bioactive glasses N2 - Sintering, crystallization, and foaming of 44.8SiO2–2.5P2O3–36.5CaO–6.6Na2O–6.6K2O–3.0CaF2 (F3) and 54.6SiO2–1.7P2O3–22.1CaO–6.0Na2O–7.9K2O–7.7MgO (13–93) bioactive glass powders milled in isopropanol and CO2 were studied via heating microscopy, differential thermal analysis, vacuum hot extraction (VHE), Infrared spectroscopy, and time-of-flight secondary ion mass spectrometry. Full densification was reached in any case and followed by significant foaming. VHE studies show that foaming is driven by carbon gases and carbonates were detected by Infrared spectroscopy to provide the major foaming source. Carbonates could be detected even after heating to 750◦C, which hints on a thermally very stable species or mechanical trapping. Otherwise, dark gray compact colors for milling in isopropanol indicate the presence of residual carbon as well. Its significant contribution to foaming, however, could not be proved and might be limited by the diffusivity of oxygen needed for carbon oxidation to carbon gas. KW - Bioactive Glass KW - Crystallization KW - Foaming KW - Sintering PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552454 DO - https://doi.org/10.1111/jace.18626 SN - 0002-7820 SP - 1 EP - 11 PB - Wiley online library AN - OPUS4-55245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, J. A1 - Behrens, H. A1 - Müller, Ralf T1 - An overview on the effect of dissolved water on the viscosity of soda lime silicate melts N2 - 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 H2Omolecules 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 timetemperature superposition principle, i.e. congruent flow curves were determined under isokomal conditions. KW - Water in glass KW - Viscosity KW - Soda lime silicate glass KW - Shear thinning KW - Nydrogen melting PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587276 DO - https://doi.org/10.1016/j.nocx.2023.100195 VL - 19 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-58727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gomes Fernandes, Roger A1 - Al-Mukadam, Raschid A1 - Bornhöft, Hansjörg A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Selle, Susanne A1 - Deubener, Joachim T1 - Viscous Sintering of Acid Leached Glass Powders N2 - 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. KW - Glass powder KW - Viscous sintering KW - Acid-leaching KW - Sinter retardation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589008 DO - https://doi.org/10.52825/glass-europe.v1i.681 VL - 1 SP - 37 EP - 53 AN - OPUS4-58900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Viscous healing of Vickers indentation–induced cracks in glass N2 - AbstractViscous healing of cracks induced by the Vickers indentation in a soda lime magnesium silicate, a soda borosilicate, and a soda aluminosilicate glass (NAS) was studied by laser scanning microscopy. Plots of the crack length, width, and depth normalized to the initial crack length versus time over viscosity merge into single master curves of each of these quantities for each glass. Despite glass properties do not differ strikingly from each other, however, these master curves strongly differ among the glasses. This finding was attributed to a different interplay of various crack healing phenomena. Lateral cracks were found to be responsible for the bulging of the sample surface around the Vickers imprint, which in turn promotes radial crack widening as the main cause of healing delay. The most rapid healing of lateral cracks was observed in NAS in which bulging and crack widening were least pronounced. KW - Crack healing KW - Glass KW - Vickers indentation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587295 DO - https://doi.org/10.1111/jace.19245 SN - 0002-7820 VL - 106 IS - 10 SP - 5795 EP - 5805 PB - Wiley AN - OPUS4-58729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinsch, Stefan A1 - Welter, T. A1 - Müller, Ralf A1 - Deubener, J. T1 - Hydrogen Permeability of Tectosilicate Glasses for Tank Barrier Liners N2 - 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. KW - Hydrogen permeation KW - Aluminosilicate glasses KW - Hydrogen storage tank KW - Glass liner PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587284 DO - https://doi.org/10.52825/glass-europe.v1i.425 VL - 1 SP - 1 EP - 11 AN - OPUS4-58728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scheffler, Franziska A1 - Fleck, Mirjam A1 - Busch, Richard A1 - Casado, Santiago A1 - Gnecco, Enrico A1 - Tielemann, Christopher A1 - Brauer, Delia S. A1 - Müller, Ralf T1 - Surface Crystallization of Barium Fresnoite Glass: Annealing Atmosphere, Crystal Morphology and Orientation N2 - Controlled oriented crystallization of glass surfaces is desired for high precision applications, since the uppermost crystal layer significantly influences the properties of the material. In contrast to previous studies, the data presented here deal with separated crystals growing at defect-free surfaces in four atmospheres with different degrees of humidity (ambient/dry air, argon and vacuum). A glass with the composition 2 BaO–TiO2–2.75 SiO2 was heat-treated at 825 °C until fresnoite (Ba2TiSi2O8) grew to a significant size. The crystal growth rate is found to increase with increasing humidity. The morphology of the crystals changes from highly distorted dendrites in the driest atmosphere (vacuum) to circular/spear-head-shaped crystals in the wettest atmosphere (ambient air), which we attribute to a decrease in viscosity of the glass surface due to water uptake. The least distorted crystals appear in the form of depressions of up to 6 µm. This has an influence on the observed crystal orientation, as measured by electron backscatter diffraction (EBSD). The pulled-in crystals change the orientation during growth relative to the flat glass surface due to an enrichment in SiO2 at the crystal fronts. This confirms that the orientation of crystals is not fixed following nucleation. KW - Fresnoite KW - Surface crystallization KW - Crystal growth KW - Crystal morphology KW - Crystal orientation KW - EBSD PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587230 DO - https://doi.org/10.3390/cryst13030475 VL - 13 IS - 3 SP - 1 EP - 17 PB - MDPI AG CY - Basel AN - OPUS4-58723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Behrens, Harald A1 - Ageo-Blanco, Boris A1 - Reinsch, Stefan A1 - Wirth, Thomas T1 - Foaming Species and Trapping Mechanisms in Barium Silicate Glass Sealants N2 - Barium silicate glass powders 4 h milled in CO2 and Ar and sintered in air are studied with microscopy, total carbon analysis, differential thermal Analysis (DTA), vacuum hot extraction mass spectroscopy (VHE-MS), Fourier-transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary-ion mass spectrometry (TOF-SIMS). Intensive foaming of powder compacts is evident, and VHE studies prove that foaming is predominantly caused by carbonaceous species for both milling gases. DTA Shows that the decomposition of BaCO3 particles mix-milled with glass powders occurs at similar temperatures as foaming of compacts. However, no carbonate at the glass surface could be detected by FTIR spectroscopy, XPS, and TOF-SIMS after heating to the temperature of sintering. Instead, CO2 molecules unable to rotate identified by FTIR spectroscopy after milling, probably trapped by mechanical dissolution into the glass bulk. Such a mechanism or microencapsulation in cracks and particle aggregates can explain the contribution of Ar to foaming after intense milling in Ar atmosphere. The amount of CO2 molecules and Ar, however, cannot fully explain the extent of foaming. Carbonates mechanically dissolved beneath the surface or encapsulated in cracks and micropores of particle aggregates are therefore probably the major foaming source. KW - Milling KW - Foaming KW - Glass powder KW - Sintering PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531227 DO - https://doi.org/10.1002/adem.202100445 SN - 1438-1656 VL - 24 IS - 6 SP - 2100445-1 EP - 2100445-13 AN - OPUS4-53122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heuser, Lina A1 - Nofz, Marianne A1 - Müller, Ralf A1 - Deubener, J. T1 - Silver dissolution and precipitation in an Na2O–ZnO–B2O3 metallization paste glass N2 - Thermally stimulated interactions between silver and glass, that is, 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 spectroscopy and energy-dispersive X-ray spectroscopy. 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, whereas 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. KW - Silver metallization paste KW - Batch reactions KW - Borate KW - Glass forming melts KW - Glass manufacturing KW - Raman spectroscopy PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559433 DO - https://doi.org/10.1111/ijag.16613 SN - 2041-1286 SP - 1 EP - 11 PB - Wiley Online Library AN - OPUS4-55943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Sintering kinetcs of GMC with small rigid inclusions T2 - 10th. Int. Symp. Ceram. Mat. and Components for Energy and Environmental Applications CY - Dresden, Germany DA - 2012-05-20 PY - 2012 AN - OPUS4-27423 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Volatile Concentration and Mobility measured by VHE-MS T2 - International Conference on Materials Science CY - Ulaanbaatar, Mongolia DA - 2012-08-20 PY - 2012 AN - OPUS4-27420 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Marzok, Ulrich A1 - Müller, Ralf A1 - Krauhausen, M. A1 - Burgstedt, F. A1 - Brode, W. T1 - Hochtemperatur shape screening keramischer Bauteile N2 - Ziel des Projekts war die Entwicklung eines Laser-Messmoduls, mit dessen Hilfe die Formänderung keramischer Bauteile während des Sinterns erfasst werden kann. Dabei sollten durch eine kontinuierliche und simultane Vermessung der Probenkontur und der Oberflächentemperatur während des Brennprozesses neue Daten zum Sinterverhalten gewonnen werden, die u. a. auch eine FE-Modellierung dieser komplexen Prozesse überprüfen und ergänzen können. Dieses Ziel sollte am Beispiel großformatiger niedrig sinternder keramischer Folien für LTCC-Anwendungen verfolgt werden. KW - Keramikherstellung KW - Sintern KW - Formmessung KW - Kontur KW - Lasermesstechnik PY - 2010 UR - http://edok01.tib.uni-hannover.de/edoks/e01fb12/685831345.pdf N1 - Schlussbericht (AZ: II D 5 – 25/06) zum Projekt im Rahmen des Programms "Unterstützung kleiner und mittlerer Unternehmen bei der Umsetzung von Innovationen in den Bereichen Messen, Normen, Prüfen und Qualitätssicherung" (MNPQ-Transfer) des Bundesministeriums für Wirtschaft und Technologie SP - 1 EP - 54 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-28373 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marzok, Ulrich A1 - Müller, Ralf A1 - Schadrack, Reinhard A1 - Krauhausen, M. A1 - Burgstedt, F. A1 - Brode, W. A1 - Reetz, R. T1 - High-temperature laser profilometry for ceramic tapes N2 - Advanced ceramics are promising key components for microsystems engineering, communication Technology and medical engineering. Driven by steadiiy increasing demands on dimensional accuracy of components and Integration density, sintering has to be controlled at an unprecedented degree of precision. Being most crucial for components of complex shape, graded or heterogeneous-composed parts like LTCC multilayers for microsystems, precise control of sintering has a decisive influence on the dimensional accuracy, mechanical integrity and reliability of sintered components. Thus, permanent or temporary shape distortions or warping during sintering may result from spatially heterogeneous microstructure and temperature distribution, e.g. during the co-firing process of green multilayer Stacks printed with metallization and other functional pastes. Whereas permanent warping can be easily measured after sintering, temporary warping during firing is more difficult to measure. Nonetheless, this effect may cause latent failures later, which often limit the applicability of ceramic components. PY - 2013 SN - 0173-9913 SN - 0196-6219 VL - 90 IS - 4 SP - E35 EP - E40 PB - Göller CY - Baden-Baden AN - OPUS4-28500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Marzok, Ulrich A1 - Müller, Ralf A1 - Schadrack, Reinhard A1 - Krauhausen, M. A1 - Burgstedt, F. A1 - Brode, W. A1 - Reetz, R. ED - Kriegesmann, J. T1 - Hochtemperatur-Laserprofilometrie an keramischen Bauteilen N2 - Es wurde ein Gerät zur In-situ-Kontrolle des Sinterns keramischer Bauteile mit Hilfe der Hochtemperatur-Lasertriangulation aufgebaut. Durch Rotation der Probe und gleichzeitiger Positionierung des Laserabstandssensors erfolgt die dreidimensionale Erfassung der Topografie der Probenoberfläche. Derzeit können flache Proben mit den Maßen < 20 cm x 20 cm x 1 cm bis 1000 °C untersucht werden. Die örtliche Wiederholpräzision des verwendeten Lasersensors beträgt 10 µm bei 20 °C und 15 µm bei 1000 °C. Die lineare Positioniergenauigkeit des Sensors liegt bei 1 µm, die Winkelauflösung der Drehung des Probentellers beträgt 0,0025 °. Daten für ein 3D-Oberflächenprofil werden in etwa 2 bis 3 Minuten erzeugt. Spezielle Linienprofile erhält man bei einer Messzeit von wenigen Sekunden. N2 - A device was designed for the in situ monitoring of sintering of ceramic components using high-temperature laser triangulation. By simultaneous rotation of the sample and positioning of the laser distance sensor at the same time a three-dimensional detection of the topography of the sample surface could be achieved. Currently, flat samples with dimensions < 20 cm x 20 cm x 1 cm can be examined up to 1000 °C. The local repeatability precision of the laser sensor used is 10 µm at 20 °C and 15 µm at 1000 °C. The linear positioning accuracy of the sensor is 1 µm, the angular resolution of the rotation of the sample plate is 0.0025 °. Data for a 3D surface profile can be obtained in about 2 to 3 minutes. Specific line profiles can be received at a measurement time of a few seconds. PY - 2013 SN - 978-3-938595-00-8 VL - 135 IS - Kap. 6.3.1.0 PB - HvB-Verlag CY - Ellerau AN - OPUS4-28967 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Gaber, Martin A1 - Gottschling, Peter T1 - Water release and crystallisation of glass powders T2 - Physics and Chemistry of Glasses / VII Symposium on Crystallization in Glasses in Liquids CY - Sheffield, England, UK DA - 2004-07-06 PY - 2004 SN - 1753-3562 SN - 0017-1050 SN - 0031-9090 SN - 1750-6697 VL - 45 IS - 2 SP - 1 EP - 5 PB - Society of Glass Technology CY - Sheffield AN - OPUS4-6237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Water release and crystallisation of glass powders T2 - VII Symposium on Crystallization in Glasses in Liquids CY - Sheffield, England DA - 2003-07-06 PY - 2003 AN - OPUS4-6238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Untersuchungen zur Sinterfahigkeit von Glaspulvern T2 - Physikalisches Kolloquium des Lehrnstuhls für Anorganische Chemie der Brandenburgischen Universität Cottbus CY - Cottbus, Germany DA - 2002-06-11 PY - 2002 AN - OPUS4-6205 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chladek, J. A1 - Müller, Ralf A1 - Weh, Lothar A1 - Reinsch, Stefan T1 - Viscous flow and surface crystallization caused by Vickers indentation PY - 2004 SN - 0927-4472 VL - 77 IS - 1 SP - 1 EP - 6 PB - Elsevier CY - Amsterdam AN - OPUS4-6235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Gaber, Martin A1 - Gottschling, Peter T1 - Volatile concentration and diffusivity determined by vacuum hot extraction T2 - XX. International Congress on Glass CY - Kyoto, Japan DA - 2004-09-26 KW - Silicate glass KW - Water KW - Hydrogen KW - Degassing KW - Diffusion coefficient PY - 2004 SP - 6 pages PB - Ceramic Society of Japan CY - Tokio AN - OPUS4-6951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gottschling, Peter A1 - Müller, Ralf A1 - Gaber, Martin T1 - Finite-Differenzen-Berechnung der Abgabe von Gasen aus Glaspulvern T2 - 78. Glastechnische Tagung CY - Nürnberg, Deutschland DA - 2004-06-07 KW - Finite Differenzen KW - Diffusion KW - Pulvermethode PY - 2004 SP - 25 EP - 29 PB - Deutsche Glastechnische Gesellschaft CY - Offenbach AN - OPUS4-6952 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Herstellung von Gläsern mittlerer Wassergehalte T2 - 79. Glastechnische Tagung CY - Würzburg, Deutschland DA - 2005-05-23 KW - Glas KW - Wassergehalt PY - 2005 SN - 3-921089-43-3 SP - 4 Seiten PB - Deutsche Glastechnische Gesellschaft CY - Offenbach AN - OPUS4-7606 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Eberstein, Markus A1 - Thiel, A. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Deubener, J. A1 - Schiller, Wolfgang Arno T1 - Lösungs- und Kristallisationsvorgänge beim Sintern von Glasmatrix-Kompositen T2 - 79. Glastechnische Tagung CY - Würzburg, Deutschland DA - 2005-05-23 KW - Glaspulver KW - Glasmatrix-Komposit KW - Sintern KW - Kristallisation PY - 2005 SN - 3-921089-43-3 SP - 7 Seiten PB - Deutsche Glastechnische Gesellschaft CY - Offenbach AN - OPUS4-10377 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Eberstein, Markus A1 - Thiel, A. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Deubener, J. A1 - Schiller, Wolfgang Arno T1 - Sinterkinetik von Glasmatrix-Kompositen mit reaktiver Dispersphase T2 - 80. Glastechnische Tagung CY - Dresden, Deutschland DA - 2006-06-12 PY - 2006 SN - 3-921089-46-8 SP - 4 Seiten PB - Verl. d. Dt. Glastechn. Ges. CY - Offenbach AN - OPUS4-14046 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Viscosity and degassing of hydrous silicate glasses T2 - 80. Glastechnische Tagung und 8th Int. Conference "Advances in Fusion and Processing of Glass" CY - Dresden, Germany DA - 2006-06-12 PY - 2006 AN - OPUS4-14259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - DMTA measurements on PTR glasses T2 - TC7, International Commission on Glass CY - Jena, Germany DA - 2006-07-23 PY - 2006 AN - OPUS4-14243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Reinsch, Stefan A1 - Meng, S. A1 - Eberstein, Markus A1 - Thiel, A. A1 - Müller, Ralf A1 - Deubener, J. T1 - Partial Solution of Dispersed alpha-Al2O3-Particles in Alumoborosilicate Glass T2 - 81. Glastechnische Tagung CY - Aachen, Deutschland DA - 2007-06-04 KW - Glasmatrixkomposite KW - Lösung KW - Sintern PY - 2007 SN - 978-3-921089-52-1 IS - CD-ROM SP - 1 EP - 5 PB - Deutsche Glastechnische Gesellschaft CY - Offenbach AN - OPUS4-16108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Moraes, Flavia A1 - Müller, Wolfgang A1 - Frischat, G.H. A1 - Müller, Ralf T1 - Corrosion and crystallization at the inner surfaces of glass bricks N2 - Glass bricks are important transparent building materials. They are produced by joining two halves of glass pressings at 600–700 °C. During this production process alkali oxides evaporate and are redeposited at the cooler inner front surfaces of the bricks. This surface layer reacts with H2O and CO2 from the residual brick atmosphere, leading to the formation of an alkali-rich silicate-hydrate layer of ≥50 nm thickness, which could be evidenced leading to a reduced nano-hardness of similar thickness, and from which NaHCO3 crystals can finally grow. Climate chamber experiments (repeated cooling between at -8 and -14 °C and reheating to 0 to 15 °C) resulted in reversible NaHCO3 crystallization and redissolution, presumably influenced by water evaporation or condensation and driven by the NaHCO3 supersaturation of the silicate-hydrate layer. Depending on the time–temperature schedule, different crystal morphologies became visible in this closed system, e.g. isolated spherical crystals, crystals arranged in chains and in double-chains, respectively, which can limit already the transmittance of the glass bricks. When a crack occurs or the brick is opened, the hygroscopic NaHCO3 crystals take up more H2O from the ambient, react irreversibly with the glass surface, finally leading to a total loss of transmittance. KW - Chemical properties KW - Chemical durability KW - Corrosion KW - Crystallization KW - Crystal growth KW - Nucleation KW - Glasses KW - Mass spectroscopy KW - Mechanical properties KW - Hardness KW - Indentation KW - Microindentation KW - Microscopy KW - Optical microscopy KW - Scanning electron microscopy KW - Optical properties KW - Optical spectroscopy KW - Oxide glasses KW - Alkali silicates KW - Soda-lime-silica KW - Surfaces and interfaces PY - 2008 DO - https://doi.org/10.1016/j.jnoncrysol.2007.07.086 SN - 0022-3093 VL - 354 IS - 2-9 SP - 284 EP - 289 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-16433 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Eberstein, Markus A1 - Reinsch, Stefan A1 - Schiller, Wolfgang Arno A1 - Deubener, J. A1 - Thiel, A. T1 - Effect of rigid inclusions on sintering of low temperature co-fired ceramics KW - Sintering KW - Glass Matrix Composites KW - Rigid Inclusion KW - Effective Viscosity KW - Kinetic Modelling KW - LTCC PY - 2007 SN - 1753-3562 SN - 0017-1050 SN - 0031-9090 SN - 1750-6697 VL - 48 IS - 4 SP - 259 EP - 266 PB - Society of Glass Technology CY - Sheffield AN - OPUS4-16211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinsch, Stefan A1 - Gaber, Martin A1 - Müller, Ralf A1 - Schiller, Wolfgang Arno T1 - Rate controlled debindering of glass ceramic composites N2 - Green compacts of ceramics, glass ceramic composites and sinter glass ceramics contain different amounts of organic materials added as pressing aids or binders. Before sintering, these organics have to burn out completely. In oxidising atmospheres, the debindering process is mostly exothermic and therefore difficult to control. This uncontrolled heat production due to locally enhanced debindering and respective gas release may cause damages in the green compact microstructure. Therefore, debindering is usually operated with very low heating rates (< 3 K/min) which requires long processing times of many hours. In this paper, we will show that it is possible to reduce the processing time for debindering dramatically by using the decomposition rate of the organic binder, detected by the weight loss of the sample, as a control factor of the furnace. T2 - 9th ESG (European Society of Glass) Conference with the Annual Meeting of the ICG Glass - "The challenge for the 21st century" CY - Trencin, Slovakia DA - 2008-06-22 KW - Debindering KW - Thermo gravimetry KW - Glass ceramic composites PY - 2005 SN - 1022-6680 SN - 1662-8985 VL - 39-40 SP - 583 EP - 586 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-17840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Apel, E. A1 - Deubener, J. A1 - Bernard, A. A1 - Müller, Ralf A1 - Kappert, H. A1 - Rheinberger, V. A1 - Höland, W. T1 - Phenomena and mechanisms of crack propagation in glass-ceramics N2 - Lithium disilicate, leucite and apatite glass-ceramics have become state-of-the-art framework materials in the fabrication of all-ceramic dental restorative materials. The goal of this study was to examine the crack propagation behaviour of these three known glass-ceramic materials after they have been subjected to Vickers indentation and to characterize their crack opening profiles (δmeas vs. (a-r)). For this purpose, various methods of optical examination were employed. Optical microscopy investigations were performed to examine the crack phenomena at a macroscopic level, while high-resolution techniques, such as scanning electron microscopy (SEM) and atomic force microscopy (AFM), were employed to investigate the crack phenomena at a microscopic level. The crack patterns of the three glass-ceramics vary from fairly straightforward to more complex, depending on the amount of residual glass matrix present in the material. The high-strength lithium disilicate crystals feature a high degree of crosslinking, thereby preventing crack propagation. In this material, the crack propagates only through the residual glass phase, which constitutes 30%–40% by volume. Having a high glass content of more than 65% by volume, the leucite and apatite glass-ceramics show far more complex crack patterns. Cracks in the leucite glass-ceramic propagate through both the glass and crystal phase. The apatite glass-ceramic shows a similar crack behaviour as an inorganic–organic composite material containing nanoscale fillers, which are pulled out in the surroundings of the crack tip. The observed crack behaviour and the calculated View the MathML source values of the three types of glass-ceramics were compared to the Kkic values determined according to the SEVNB method. KW - Glass KW - Viscosity KW - Water content PY - 2008 DO - https://doi.org/10.1016/j.jmbbm.2007.11.005 SN - 1751-6161 VL - 1 IS - 4 SP - 313 EP - 325 PB - Elsevier CY - Amsterdam AN - OPUS4-18308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, J. A1 - Behrens, H. A1 - Müller, Ralf A1 - Zietka, S. A1 - Reinsch, Stefan T1 - Kinetic fragility of hydrous soda-lime-silica glasses N2 - The effect of hydration on the kinetic fragility of soda-lime-silica glasses was investigated by viscometry in the glass transition range. Water-bearing glasses were prepared from industrial float glass (FG) and a ternary model glass (NCS = 16Na2O 10CaO 74SiO2 in mol%) by bubbling steam through the melt at 1480 °C and up to 7 bar. Additionally, a sodium borosilicate glass (NBS = 16Na2O 10B2O3 74SiO2 in mol%) was hydrated under equal conditions. As detected by infrared spectroscopy water dissolves in the glasses exclusively as OH-groups. The hydration resulted in a total water content CW up to ~ 0.2 wt% for FG, NCS and NBS glasses. Kinetic fragility, expressed by the steepness index m, was determined from the temperature dependence of η at the glass transition. Viscosity data from previous studies on hydrous float glasses (CW > 1 wt%) were surveyed together with literature data on the (H2O)–Na2O–CaO–SiO2, (H2O)–Na2O–SiO2 and (H2O)–SiO2 systems to expand the range of water concentration and bulk composition. We could demonstrate that m decreases for all glasses although water is dissolved as OH and should depolymerize the network. An empirical equation of the general type m = a - b logCW where a, b are fitting parameters, enables m to be predicted, for each glass series as function of the water content CW. The enlarged data base shows that the parameter B of the Arrhenius viscosity-temperature relation decreases much stronger than the isokom temperature at the glass transition. KW - Soda-lime-silica KW - Fragility KW - Viscosity KW - Water in glass PY - 2008 DO - https://doi.org/10.1016/j.jnoncrysol.2008.04.021 SN - 0022-3093 VL - 354 IS - 42-44 SP - 4713 EP - 4718 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-18187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Crystallization in multicomponent systems. Glasses for LTCC T2 - Meeting 2008 des TC7 der ICG am Rande der 9th ESG Conf. with the Annual Meeting of the ICG Glass-The challenge for the 21st century CY - Trencín, Slovakia DA - 2008-06-22 PY - 2008 AN - OPUS4-18106 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Eberstein, Markus A1 - Deubener, J. A1 - Thiel, A. A1 - Schiller, Wolfgang Arno T1 - Effects of dispersed Al2O3 particles on sintering of LTCC N2 - The sintering of Low Temperature Co-fired Ceramics prepared from alumoborosilicate glass- and Al2O3 powders of similar small particle size was studied by dilatometry, heating microscopy, microstructure analysis, glass- and effective viscosity measurements. The steric effect of Al3O3 inclusions was studied using a gnon-reactiveh model composite. With increasing Al3O3 volume fraction (Φ ≤ 0.45), sintering decelerates and its final stage shifts to higher temperature. The attainable shrinkage is reduced as Al2O3 particle clusters bearing residual pores become more frequent. The kinetics of sintering could be described formally superposing the weighed contributions of differentially sized and randomly composed glass-crystal particle clusters and assuming a sintering rate controlled by the effective matrix viscosity, which increases with Φ and with progressive wetting of Al2O3 particles during densification. The "reactive" model composite shows significant dissolution of Al2O3 into the glass, which has two opposed effects on sintering: reducing Φ and increasing glass viscosity. For the present case (Φ = 0.25), the latter effect dominates and sintering is retarded by Al2O3 dissolution. Crystallization of wollastonite starts after full densification. Dissolution of Al2O3 was found to promote the subsequent growth of anorthite. KW - LTCC KW - Glass matrix composites KW - Al2O3-inclusions KW - Sintering kinetics PY - 2005 SN - 1022-6680 SN - 1662-8985 VL - 39-40 SP - 375 EP - 380 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-18441 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinsch, Stefan A1 - Nascimento, M.L.F. A1 - Müller, Ralf A1 - Zanotto, E. D. T1 - Crystal growth kinetics in cordierite and diopside glasses in wide temperature ranges N2 - We measured and collected literature data for the crystal growth rate, u(T), of µ-cordierite (2MgO · 2Al2O3 · 5SiO2) and diopside (CaO · MgO · 2SiO2) in their isochemical glass forming melts. The data cover exceptionally wide temperature ranges, i.e. 800–1350 °C for cordierite and 750–1378 °C for diopside. The maximum of u(T) occurs at about 1250 °C for both systems. A smooth shoulder is observed around 970 °C for µ-cordierite. Based on measured and collected viscosity data, we fitted u(T) using standard crystal growth models. For diopside, the experimental u(T) fits well to the 2D surface nucleation model and also to the screw dislocation growth mechanism. However, the screw dislocation model yields parameters of more significant physical meaning. For cordierite, these two models also describe the experimental growth rates. However, the best fittings of u(T) including the observed shoulder, were attained for a combined mechanism, assuming that the melt/crystal interface growing from screw dislocations is additionally roughened by superimposed 2D surface nucleation at large undercoolings, starting at a temperature around the shoulder. The good fittings indicate that viscosity can be used to assess the transport mechanism that determines crystal growth in these two systems, from the melting point Tm down to about Tg, with no sign of a breakdown of the Stokes–Einstein/Eyring equation. KW - Crystal growth KW - Oxide glasses KW - Silicates KW - Kristallwachstumsgeschwindigkeit KW - Kinetik KW - Silikatgläser PY - 2008 DO - https://doi.org/10.1016/j.jnoncrysol.2008.09.007 SN - 0022-3093 VL - 354 IS - 52-54 SP - 5386 EP - 5394 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-18383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zietka, S. A1 - Deubener, J. A1 - Behrens, H. A1 - Müller, Ralf T1 - Glass transition and viscosity of hydrated silica glasses N2 - The viscosity of silica glasses with different water contents was measured by penetration of sapphire microspheres in the range from 1012-1014·7 Pas at ambient pressure. Commercial silica glasses were used together with hydrous silica glasses, which were prepared by melting glass powder plus water in an internally heated pressure vessel at 2-3 kbar and 1350-1450°C. The temperature dependence of the viscosity of silica glasses with total water contents Cw of 5·4×10-4, 7·0×10-4, 1·00×10-2, and 1·55×10-2(Cw in mass fractions) can be described by Arrhenius equations. From the results, the linear dependence of the T12 isokom (K) with the logarithm of the water content was determined as T12=192-409 logCw. The analysis of the compositional dependence of the T12 isokom in the H2O-Na2O-SiO2 system reveals a temperature depression of up to 200 K for mixed water- and sodium-bearing glasses compared to H2O-SiO2 and Na2O-SiO2 glasses with same molar silica content. From these findings we conclude that protons may contribute significantly to the mixed alkali effect in glasses. KW - Wassergehalt KW - Silicatgläser KW - Viskosität PY - 2007 SN - 1753-3562 SN - 0017-1050 SN - 0031-9090 SN - 1750-6697 VL - 48 IS - 6 SP - 380 EP - 387 PB - Society of Glass Technology CY - Sheffield AN - OPUS4-18396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, J. A1 - Bornhöft, H. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Lumeau, J. A1 - Glebova, L.N. A1 - Glebov, L.B. T1 - Viscosity, relaxation and elastic properties of photo-thermo-refractive glass KW - Ultrasonic relaxation KW - Silicates KW - Rheology KW - Structural relaxation KW - Viscosity PY - 2009 DO - https://doi.org/10.1016/j.noncrysol.2008.10.002 SN - 0022-3093 VL - 355 SP - 126 EP - 131 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-18671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiller, Wolfgang Arno A1 - Müller, Ralf A1 - Eberstein, Markus A1 - Reinsch, Stefan A1 - Rabe, Torsten T1 - Sintering of LTCC N2 - Low Temperature Co-fired Ceramic materials (LTCC) have attracted growing interest in recent years since they are promising candidates for highly integrated ceramic packaging. This paper surveys materials concepts of related glass ceramic composites (GCC) and discusses unsolved problems and challenges. The densification of GCC based on "viscous sintering" may be affected by steric effects and partial dissolution of dispersed crystal particles, crystallization and phase boundary reactions. KW - Sintering KW - Glass ceramic composites KW - Viscosity KW - Densification KW - Modelling PY - 2008 SN - 0173-9913 SN - 0196-6219 VL - 85 IS - 13 SP - 12 EP - 17 PB - Göller CY - Baden-Baden AN - OPUS4-19086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eberstein, Markus A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Deubener, J. A1 - Schiller, Wolfgang Arno T1 - Sintering of glass matrix composites with small rigid inclusions KW - Glass ceramics KW - Inclusions KW - Sintering KW - Mixing KW - Powders KW - Solid-state reaction PY - 2009 DO - https://doi.org/10.1016/j.jeurceramsoc.2009.02.007 SN - 0955-2219 SN - 1873-619X VL - 29 IS - 12 SP - 2469 EP - 2479 PB - Elsevier CY - Oxford AN - OPUS4-19570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Meszaros, Robert A1 - Peplinski, Burkhard A1 - Reinsch, Stefan A1 - Eberstein, Markus A1 - Schiller, Wolfgang Arno A1 - Deubener, J. T1 - Dissolution of alumina, sintering, and crystallization in glass ceramic composites for LTCC KW - LTCC KW - Sintering KW - Crystallization KW - Alumina dissolution KW - Rietveld analysis PY - 2009 DO - https://doi.org/10.1111/j.1551-2916.2009.03089.x SN - 0002-7820 SN - 1551-2916 VL - 92 IS - 8 SP - 1703 EP - 1708 PB - Blackwell Publishing CY - Malden AN - OPUS4-20676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Dissolution of alumina in GMC for LTCC T2 - 8th Pacific Rim Conf. on Ceramic and Glass Technology CY - Vancouver, Canada DA - 2010-05-31 PY - 2010 AN - OPUS4-21416 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaber, Martin A1 - Müller, Ralf A1 - Brzezinka, Klaus-Werner A1 - Peuker, Christel A1 - Langer, A. T1 - Analyse von Wasserstoff in Quarzglas T2 - 76. Glastechnische Tagung CY - Bad Soden, Deutschland DA - 2002-05-27 PY - 2002 SP - 242 EP - 245 PB - DGG, Deutsche Glastechnische Gesellschaft e.V. CY - Frankfurt/M. AN - OPUS4-1636 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiller, Wolfgang Arno A1 - Eberstein, Markus A1 - Müller, Ralf T1 - Glass Ceramic Composites for Microsystems PY - 2003 SN - 0927-4472 VL - 76 C1 SP - 54 EP - 59 PB - Elsevier CY - Amsterdam AN - OPUS4-2592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Peplinski, Burkhard A1 - Müller, Ralf A1 - Wenzel, Klaus-Jürgen A1 - Sojref, Regine A1 - Schultze, Dietrich ED - Delhez, R. T1 - An X-ray powder diffration investigation of a fine-grained synthetic a-cordierite powder T2 - 6th European Powder Diffraction Conference CY - Budapest, Hungary DA - 1998-08-22 KW - Alpha-cordierite KW - Indialite KW - Standard material KW - Back-filling specimen mount technique PY - 2000 SN - 0-87849-847-8 SN - 0255-5476 SP - 150 EP - 155 PB - Trans Tech Publ. CY - Uetikon-Zürich AN - OPUS4-1195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Altantsog, Pagvajav A1 - Ojunbileg, L. A1 - Tserenshimed, M. A1 - Chadraabal, Shgdariin A1 - Müller, Ralf A1 - Nofz, Marianne A1 - Gaber, Martin A1 - Batdemberel, G. A1 - Sangaa, D. T1 - Some experimental results of glass melting by using sands from Buir nuur PY - 2002 VL - 1 SP - 103 EP - 118 AN - OPUS4-3113 LA - mon AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chadraabal, Shgdariin A1 - Gaber, Martin A1 - Müller, Ralf A1 - Altantsog, Pagvajav A1 - Tserenshimed, M. A1 - Ojunbileg, L. T1 - Degassing features of quartz crystals from the Mongolian pegmatite deposite Gorkhi PY - 2001 VL - 28 SP - 76 EP - 83 AN - OPUS4-3114 LA - mon AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmelzer, J.W.P. A1 - Müller, Ralf A1 - Möller, J. A1 - Gutzow, I.S. T1 - Elastic stresses, stress relaxation and crystallisation: theory of nucleation PY - 2002 SN - 0031-9090 VL - 43C SP - 291 EP - 300 PB - Thornton CY - Sheffield AN - OPUS4-3116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Reinsch, Stefan A1 - Schadrack, Reinhard A1 - Müller, Ralf A1 - Behrens, H. A1 - Deubener, J. T1 - Bestimmung der Glastransformationstemperatur wasserhaltiger Gläser T2 - 80. Glastechnische Tagung CY - Dresden, Deutschland DA - 2006-06-12 PY - 2006 SN - 3-921089-46-8 SP - 1(?) EP - 5(?) PB - Verl. d. Dt. Glastechn. Ges. CY - Offenbach AN - OPUS4-12552 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eberstein, Markus A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Rabe, Torsten A1 - Schiller, Wolfgang Arno A1 - Thiel, A. A1 - Deubener, J. T1 - Kinetic Modeling of LTCC-Shrinkage T2 - 3rd International Conference and Exhibition on Ceramic Interconnect and Ceramic Microsystems Technologies (CICMT 2007) CY - Denver, CO, USA DA - 2007-04-23 KW - LTCC KW - Glass matrix composites KW - Inclusions KW - Sintering kinetics KW - Modeling PY - 2007 SP - 1 EP - 8 PB - American Ceramic Soc. CY - Denver AN - OPUS4-14948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eberstein, Markus A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Rabe, Torsten A1 - Schiller, Wolfgang Arno A1 - Thiel, A. A1 - Deubener, J. T1 - Kinetic Modeling of LTCC Shrinkage: Effect of Alumina Content N2 - We studied sintering of LTCC-type glass matrix composites (GMCs) consisting of small glass and alumina particles of equal size. Primarily, crystals act as rigid inclusions, decelerating the densification rate. In later stages, they also dissolve, partially increasing the viscosity. Release of alumina finally induces crystallization of alumosilicates, which enables post-firing stability. To study both effects, two model GMCs were prepared: an α-Al2O3 + barium alumoborosilicate glass (BABS)–GMC, which shows neither significant dissolution nor crystallization, and an α-Al2O3 + calcium alumoborosilicate glass (CABS)–GMC, which dissolves readily and promotes crystallization. The kinetics of shrinkage for both GMC were modeled by utilizing Frenkel theory for the early stage and Mackenzie–Shuttleworth theory for the late stage, assuming that sintering is superimposed by the weighted contributions of triparticle glass–crystal clusters, their random occurrence (ideal mixing), and a shrinkage rate controlled by the GMC effective viscosity. In agreement with modeling, the experimental results showed that the shrinkage rate of BABS–GMC decreases progressively for crystal volume fractions Φ > 0.15. The attainable shrinkage is reduced by up to 8% for Φ = 0.45. For the CABS–GMC with Φ = 0.25, a reduction of Φ to 0.20 was evident due to partial α-Al2O3 dissolution. This effect was found able to increase the sintering temperature by ~50–60 K. KW - LTCC KW - Glas Matrix Composites KW - Inclusions KW - Sintering Kinetics KW - Modeling PY - 2007 SN - 1551-4897 VL - 4 IS - 4 SP - 173 EP - 180 CY - Washington, DC AN - OPUS4-16506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Eberstein, Markus A1 - Deubener, J. A1 - Thiel, A. A1 - Schiller, Wolfgang Arno ED - J.G. Heinrich, ED - C.G. Aneziris, T1 - Effect of dispersed Al2O3 particles on sintering of glass matrix composites T2 - 10th International Conference of the European Ceramic Society CY - Berlin DA - 2007-06-17 KW - LTCC KW - Glass matrix composites KW - Inclusions KW - Sintering kinetics KW - Modelling PY - 2007 SN - 3-87264-022-4 SP - 290 EP - 295 PB - Göller CY - Baden-Baden AN - OPUS4-17445 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Effects of dispersed Al2O3 particles on sintering of LTCC T2 - 9th ESG Conf. with the Annual Meeting of the ICG Glass - The challenge for the 21st century CY - Trencín, Slovakia DA - 2008-06-22 PY - 2008 AN - OPUS4-16688 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Heinz A1 - Peuker, Christel A1 - Müller, Ralf T1 - Zuordnung von Hydroxylgruppen- und Wasserbanden in den Schwingungsspektren wasserarmer Silicatgläser T2 - 75. Glastechnische Tagung CY - Wernigerode, Deutschland DA - 2001-05-21 PY - 2001 PB - DGG, Deutsche Glastechnische Gesellschaft e.V. CY - Frankfurt/M. AN - OPUS4-1071 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmelzer, J.W.P. A1 - Müller, Ralf A1 - Möller, J. A1 - Gutzow, I.S. T1 - Theory of nucleation in viscoelastic media: application to phase formation in glassforming melts N2 - Glassforming melts behave, in the vicinity of the temperature of vitrification Tg, as viscoelastic bodies. A general theory of nucleation in a viscoelastic body developed elsewhere is applicable to the description of phase formation processes in such systems. The present contribution is directed to the demonstration of the relevance of this proposed general theory to describing phase transformation processes in glassforming melts. The application of the theory is shown to explain a number of experimental results on crystallization of glassforming melts, which have not found a satisfactory interpretation so far. PY - 2003 DO - https://doi.org/10.1016/S0022-3093(02)01428-X SN - 0022-3093 VL - 315 SP - 144 EP - 160 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-2078 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Moraes, Flavia A1 - Frischat, G. H. A1 - Heide, G. A1 - Müller, Wolfgang A1 - Müller, Ralf T1 - Korrosions- und Kristallisationsphänomene an der Innenoberfläche von Glasbausteinen T2 - 77. Glastechnische Tagung CY - Leipzig, Deutschland DA - 2003-05-26 PY - 2003 VL - 77 SP - 71 EP - 74 PB - DGG CY - Offenbach AN - OPUS4-2527 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Kristallwachstumsgeschwindigkeit und -mechanismen von mu-Cordierit zwischen 800 und 1350°C T2 - 77. Glastechnische Tagung CY - Leipzig, Deutschland DA - 2003-05-26 PY - 2003 VL - 77 SP - 1 EP - 4 PB - DGG CY - Offenbach AN - OPUS4-2526 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, Joachim A1 - Müller, Ralf A1 - Behrens, H. A1 - Heide, G. T1 - Water and the glass transition temperature of silicate melts N2 - Literature data on the effect of water on the glass transition in silicate melts are gathered for a broad range of total water content cw from 3 × 10-4 to 27 wt%. In terms of a reduced glass transition temperature Tg*=Tg/TgGN, where TgGN is Tg of the melt containing cw?0.02 wt% total water, a uniform dependence of Tg* on total water content (cw) is evident for silicate melts. Tg* decreases steadily with increasing water content, most strongly at the lowest water content where H2O is dominantly dissolved as OH. For water-rich melts, the variation of Tg* is less pronounced, but it does not vanish even at the largest water contents reported (?27 wt%). Tg* vs. cw is fitted by a three-component model. This approach accounts for different transition temperatures of the dry glass, hydroxyl and molecular water predicting Tg* as a weighted linear combination of these temperatures. The required but mostly unknown water speciation in the glasses was estimated using IR-spectroscopy data for hydrous sodium trisilicate and rhyolite. PY - 2003 DO - https://doi.org/10.1016/S0022-3093(03)00472-1 SN - 0022-3093 VL - 330 SP - 268 EP - 273 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-3120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Volatile concentration and diffusivity determined by vacuum hot extraction T2 - XX. International Congress on Glass CY - Kyoto, Japan DA - 2004-09-26 PY - 2004 AN - OPUS4-3537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Ralf A1 - Gaber, Martin A1 - Gottschling, Peter T1 - Water release from silicate glass powders PY - 2002 SN - 0946-7475 SP - 92 EP - 97 PB - Verl. d. Dt. Glastechn. Ges. CY - Offenbach AN - OPUS4-3117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Nascimento, M.L.F. A1 - Zanotto, E. D. T1 - Crystal Growth Mechanism in Cordierite and Diopside Glasses in Wide Temperature Ranges T2 - XX. International Congress on Glass CY - Kyoto, Japan DA - 2004-09-26 KW - Cordierite KW - Diopside KW - Glass KW - Crystal growth PY - 2004 SP - 6 pages PB - Ceramic Society of Japan CY - Tokio AN - OPUS4-4389 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -