使用AEM和HREM研究了添加纳米SiC颗粒和同时添加纳米SiC颗粒及SiC晶须的两种Si3N4 复合陶瓷材料的微观组织和断裂机制。结果表明 ,部分SiC颗粒分布在Si3N4 晶内 ,SiC晶须分布在Si3N4 晶粒之间 ,SiC颗粒和晶须与Si3N4 界面之间不存在第二相组织 ,非晶组织大多分布在Si3N4 三叉晶界。断裂裂纹主要沿晶界和相界面扩展 ,也可能穿过少数Si3N4 晶粒。当裂纹扩展遇到SiC颗粒和 /或SiC晶须时 ,会发生转弯 ,产生分枝裂纹或微裂纹并在Si3N4 晶内和Si3N4 晶粒的断裂表面引起晶格畸变 ,这降低了裂纹扩展能量 ,从而改善复合陶瓷材料的断裂强度和断裂韧性 AEM and HREM were used to study the microstructure and fracture mechanism of two kinds of Si3N4 composite ceramics added with nano-SiC particles and nano-SiC particles and SiC whiskers. The results show that some SiC particles are distributed in the Si3N4 crystal, the SiC whiskers are distributed between the Si3N4 crystal grains, the second phase does not exist between the SiC particles and the whiskers and the Si3N4 interface, and the amorphous structures are mostly distributed in the Si3N4 trigeminal grain boundaries . Fracture cracks mainly along the grain boundary and phase interface, may also cross a small number of Si3N4 grains. When the crack propagation encounters SiC particles and / or SiC whiskers, turning occurs, branching or micro-cracking occurs and lattice distortion is caused in the Si3N4 crystal and the fracture surface of Si3N4 crystal grains, which reduces the crack propagation energy, Thus improving the fracture strength and fracture toughness of the composite ceramic material