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 JF - European journal of glass science and technology / B 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 - 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 JF - Journal of the American ceramic society 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 - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Sintering and foaming of bioactive glasses JF - Journal of American Ceramic Society 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 - CONF A1 - Müller, Ralf A1 - Agea-Blanco, Boris A1 - Blaeß, Carsten A1 - Reinsch, Stefan A1 - Behrens, H 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 - 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 JF - Advanced Engineering Materials 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 T1 - Alkali and alkaline earth zinc and lead borate glasses: Sintering and crystallization JF - Journal of Non-Crystalline Solids: X 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 - 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 JF - Journal of the European Ceramic Society 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 - Schiller, Wolfgang Arno A1 - Müller, Ralf A1 - Eberstein, Markus A1 - Reinsch, Stefan A1 - Rabe, Torsten T1 - Sintering of LTCC JF - Ceramic Forum International : cfi 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 - CONF A1 - Müller, Ralf T1 - Sintering and crystallization of glass powders – effects, challenges and chances N2 - Chemical variability is a main strength of glass. Glass powders are therefore promising candidates for manufacturing a broad diversity of sintered materials like sintered ¬glass-ceramics, glass matrix composites or glass bonded ceramics with tailored mechanical, thermal, electrical and optical properties and complex shape. Its wide and precise adjustability makes this class of materials, even if it may not be obvious at first sight, a key component of advanced technologies. Manufacture and processing of initial glass powders often allow even more flexibility in materials design. At the same time, however, they can cause additional problems. The lecture illustrates possible consequences of glass powder processing upon glass crystallization and sintering as well as chances for targeted utilization. Simple kinetic models describing the effect of particle size distribution, surface crystallization and rigid inclusions on sintering as well effects of different milling and seeding on sinter crystallization are presented. T2 - Institutskolloquium CSIC CY - Madrid, Spain DA - 28.4.2016 KW - Glass KW - Powders KW - Sintering KW - Crystallization KW - SOFC KW - LTCC PY - 2016 AN - OPUS4-38333 LA - eng 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 JF - Frontiers in Materials Glass Science 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 -