TY - GEN A1 - Müller, Ralf T1 - Sintering and foaming of silicate N2 - Glass powders are promising candidates for manufacturing a broad diversity of sintered materials like sintered glass-ceramics, glass matrix composites or glass bonded ceramics with properties and complex shape. Powder processing, however, can substantially affect sinterability, e.g. by promoting surface crystallization. On the other hand, densification can be hindered by gas bubble formation for slow crystallizing glass powders. Against this background, we studied sintering and foaming of silicate glass powders with different crystallization tendency for wet milling and dry milling in air, Ar, N2, and CO2 by means of heating microscopy, DTA, Vacuum Hot Extraction (VHE), SEM, IR spectroscopy, XPS, and ToF-SIMS. In any case, foaming activity increased significantly with progressive milling. For moderately milled glass powders, subsequent storage in air could also promote foaming. Contrarily, foaming could be substantially reduced by milling in water and 10 wt% HCl. Although all powder compacts were uniaxially pressed and sintered in air, foaming was significantly affected by different milling atmosphere and was found most pronounced for milling in CO2 atmosphere. Conformingly, VHE studies revealed that foaming is mainly driven by carbonaceous species, even for powders milled in other gases. Current results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. T2 - ICG Annual Meeting 2018 CY - Yokohama, Japan DA - 23.09.2018 KW - Foaming KW - Glass KW - Powder KW - Sintering PY - 2018 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/46474 AN - OPUS4-46474 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany