TY - CONF A1 - Müller, Ralf A1 - Agea Blanco, Boris A1 - Reinsch, Stefan 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 - Marzok, Ulrich A1 - Müller, Ralf A1 - Reetz, R. A1 - Lauven, G. T1 - 3D High-temperature laser profilometry during sintering N2 - Most crucial for components of complex shape or heterogeneous micro structure, precise control of sintering has decisive influence on dimensional accuracy, mechanical integrity and reliability of sintered components. In these cases, only in situ 3D high-temperature shape screening during shrinkage would allow revealing temporary sinter warpage and hereby caused potential defects. Against this background, nokra Optische Prüftechnik und Automation GmbH, HTM Reetz GmbH and BAM developed a testing device for in situ 3D shape screening for ceramic and glass-ceramic tapes up to 1000°C by means of high-temperature laser profilometry. The local repeatability of the sample-sensor distance (sample height profile) is 10 µm at 1000°C. Current work is focused on dropping these restrictions in sample shape and temperature. In a second testing device, currently being in development, samples up to 5 cm x 5 cm x 5 cm can be measured at temperatures up to 1500°C.The presentation illustrates the current state of this work and possible applications of the method. T2 - 92. DKG Jahrestagung CY - Berlin, Germany DA - 19. 03. 2017 KW - Laser profilometry KW - 3D High-temperatue shape screening KW - Sintering PY - 2017 AN - OPUS4-40449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Haung, S. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - NbC grain growth control and mechanical properties of Ni bonded NbC cermets prepared by vacuum liquid phase sintering N2 - The current study reports on the effect of the sintering temperature and secondary carbide (VC, Mo2C and TiC) additions on the microstructure and concommitant Vickers hardness (HV30) and fracture toughness of Ni-bonded NbC cermets. T2 - 19. Plansee Seminar CY - Reutte, Austria DA - 29.05.2017 KW - Cermet KW - Hard materials KW - Sintering KW - Microstructure KW - Core-rim KW - Mechanical properties PY - 2017 AN - OPUS4-40658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - NbC grain growth control and mechanical properties of Ni bonded NbC cermets prepared by vacuum liquid phase sintering N2 - The current study reports on the effect of the sintering temperature and secondary carbide (VC, Mo2C and TiC) additions on the microstructure and concommitant Vickers hardness (HV30) and fracture toughness of Ni-bonded NbC cermets. All cermets were prepared by pressureless sintering in vacuum. Detailed microstructural investigation was performed by electron probe microanalysis (EPMA) and X-ray diffraction (XRD) analysis. Sintering results indicated that both the sintering temperature and secondary carbide additions had a significant effect on the properties of NbC-Ni cermets. Nickel pools and residual pores were observed in the cermets sintered at temperatures ≤ 1340 °C. Increasing of the sintering temperature up to 1420 or 1480 °C resulted in fully densified NbC-Ni based cermets composed of homogeneous contrast cubic NbC grains for the single carbide (VC or Mo2C) modyfied system, whereas core-rim structured NbC grains were observed with the additon of TiC + VC or TiC+Mo2C. The secondary carbide doped cermets with 5–10 vol.% VC/Mo2C and 10 vol.% TiC showed a significantly improved hardness and fracture toughness, as compared to the plain NbC-Ni cermets. T2 - 19. Plansee Seminar CY - Reutte, Austria DA - 29.05.2017 KW - Cermet KW - Hard materials KW - Sintering KW - Microstructure KW - Core-rim KW - Mechanical properties PY - 2017 SP - HM 13/1 EP - HM 13/11 AN - OPUS4-40592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -