本文研究了高温等静压（HIP）后处理工艺对液相烧结SiC陶瓷的显微结构及力学性能的影响．实验表明，HIP后处理的效果随烧结助剂的不同及液相烧结温度的变化而改变．Ar气氛条件下的HIP后处理可以提高液相烧结SiC的密度，减少或消除内部气孔等结构缺陷，但不引起晶粒的长大．N2条件下的HIP后处理除了具有Ar－HIP后处理的优点外，由于表面SiC与N2之间的反应生成的Si3N4可以有效地改善表面状态，从而达到表面改性，提高SiC陶瓷的力学性能．结构分析表明，经N2-HIP后处理，表面氮化层中晶粒细小，结构致密．同时，HIP后处理的效果还受液相烧结SiC陶瓷显微结构的影响，当液相烧结SiC的烧结温度较低，晶粒较细时，经HIP后处理，尤其是N2-HIP后处理，强度和韧性均有较大幅度的提高．
The microstructure and mechanical properties of liquid phase sintered SiC followed by post-hot isostatic pressing (HIP) were studied. It is indicated that the effect of post-HIP treatment is changed with the variation of
sintering aids and temperature of liquid phase sintering. After Ar-HIP treatment, the density of SiC is increased and the inside pores are
diminished, but grain growth is depressed. Besides the advantages of the Ar-HIP, N2-HIP can modify the surface state because of the reaction
between SiC and N2 so that the mechanical properties are improved. Microstructure analysis has shown that after N2-HIP treatment,
grain size is decreased and the density is increased. Meanwhile, the results of post-HIP treatment are highly affected by the microstructure
of the liquid phase sintered SiC. When the sintering temperature is relatively lower and the grain size is smaller, after post-HIP treatment, esp.
N2-HIP treatment, bending strength and fracture toughness of the liquid phase sintered SiC are improved greatly.
参考文献
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