Fabrication of SiC Whisker-Si sub 3 N sub 4 Composite Materials and Their Physical Properties

摘要

The forming method and physical properties of SiC whisker-Si sub 3 N sub 4 composite materials were studied. The slurry of Si sub 3 N sub 4 powder mixed with SiC whiskers (10, 20, and 30 wt %) was preformed into thin slabs. About fifteen slabs were stacked in a graphite mold and hot-pressed under the conditions of 1700 to 1800 exp 0 C, 30 to 120 minutes and 400 kg/cm exp 2 . A large majority of the composites achieved the relative densities over 99%. Accordingly, the present preforming method is considered to be one of advantageous methods for the densification of SiC whisker-Si sub 3 N sub 4 composites. Bending strength and fracture toughness showed maxima at the sintering time of 60 to 90 minutes, but their enlargement was not observed by addition of SiC whiskers. Fracture energy of the composites was larger than that of without whisker. Microhardness of the composites increased with increasing the content of SiC whisker and no remarkable dropping in microhardness was observed even at 1200 exp 0 C. 12 figures. (ERA citation 08:010370)