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摘要
High density SiC ceramics with 4 wt.% (in mass) and without Al(2)O(3) as sintering additive were fabricated by nano-SiC as raw materials under different technical condition (1000-1300 degrees C, 4.0-4.5 GPa, 15-35 min) using China-type twain face anvils apparatus. The effect of sintering parameters on the mechanical property of SiC ceramics was studied. The sintered SiC was characterized by XRD, SEM, EDS and micro-hardness instruments. The results indicated that pure SiC could be sintered to high density (SiC sintered at the condition of 4.5 GPa/1250 degrees C/35 min could reach 96% of its theory density) by ultra-high pressure technique, and Al(2)O(3) is a kind of effective sintering additive. SiC doping with only 4% Al(2)O(3) could be sintered to full density by ultra-high pressure technique. The grain size was kept in nano-scale, its crystal lattice shrinkage was about 0.45%, while beta-SiC has not changed. The micro-hardness and density were increased with increasing sintering temperature, pressure and holding time. The ultra-high pressure method could effectively lower the sintering temperature, shorten the sintering time and reducing the usage of sintering additive. Under 4.5 GPa the lowest sintering temperature was 1300 degrees C, which was above 600 degrees C lower than that for conventional liquid-phase sintering and its density is much higher.
- 出版日期2010-12
- 单位中国工程物理研究院
