液相烧结SiC陶瓷的微观结构

采用Al2O3、Y2O3为助烧剂，液相烧结获得了致密的α－SiC和β－SiC陶瓷，并研究了SiC了烧结体的物相组成和微观结构。实验结果表明，Al2O3,Y2O3原位形成了YAG，材料以液相烧结机制致密化，α－SiC通过溶解和再析出机制，促进晶体生长，并形成“Core/Shell”结构，物相分析表明，β－SiC陶瓷粉末在烧结过程中发生β→a的相变，微观结构观察显示，β-SiC陶瓷中生成了长柱状晶粒。

Microstructure of Liquid Phase Sintered SiC

α-SiC ceramics and β-SiC ceramics were obtained by hot-pressing through using Al2O3 and Y2O3 as sintering additives. The phase composition and microstructure of the sintered SiC were investigated. α-SiC ceramics were densified based on the liquid phase sintering mechanism, in which YAG was formed in situ by the reaction of Al2O3 and Y2O3. The relatively large grains show that grains grow through solution-reprecipitation and "Core/shell" structure is formed. The phase analysis revealed that the phase transformation of inβ-SiC ceramics occurred during sintering. The morphology indicated that the rod-like grains were formed in theβ-SiC ceramics.