作者: Valentina Medri , Claudio Capiani , Alida Bellosi
DOI: 10.1111/J.1744-7402.2009.02484.X
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摘要: In view of the perspective to produce near-net shapes ultra-refractory ceramics, ZrB2–SiC composite were produced by slip casting on plaster mould and pressureless sintered at 2150°C with a holding time 120 min, using silicon nitride as sintering aid. After sintering, slip-cast samples reached very high relative density over 98%, while for comparison, cold isostatic pressed was about 94%. Traces formation secondary phases such B4C, graphite, BN found in all samples, no grain boundary revealed. RT flexural strength as-sintered cast bars affected presence an external porous layer coarse ZrB2 particles, 1500°C increased, glassy sealed superficial defects. Because absence softening phases, subcritical crack growth did not occur during high-temperature tests.