Si3N4/TiC纳米复合陶瓷材料显微结构

利用日立H-800透射电境、日立S-570型扫描电境及RAX-10A型X射线衍射仪对Si3N4/TiC纳米复合陶瓷材料的微观组织、结构和成分进行了研究.结果表明,TiC纳米颗粒弥散分布在基体β-Si3N4晶内和晶界,所制备的材料为晶内/晶间混合型纳米复合陶瓷.通过对Si3N4/TiC纳米复合陶瓷材料断裂方式的观察表明,材料断裂为沿晶断裂和穿晶断裂复合型,纳米粒子对裂纹扩展起到偏转和钉扎作用.纳米Si3N4颗粒的加入促进了基体长柱状β-Si3N4晶粒多峰分布的形成,类晶须晶粒在裂纹扩展过程中产生桥接和拔出.

Microstructure of Si3N4/TiC nanocomposite ceramics

The microstructure and composition of Si_3N_4/TiC nanocomposite have been investigated by means of H-800 transmission electron microscope (TEM), S-570 scanning electron microscope and RAX-10A X-ray diffraction. The study shows that TiC nanoparticles distribute in the matrix and at the grain boundaries. The results indicate that the microstructure of the composite materials is characterized by the mixture of intergranular and intragranular phases. The fracture characteristics is mixed by intergranular fracture and transgranular fracture. Low contents of nano particles can refine matrix grains and lead to the crack deflection as well as crack pinning. The multiplex microstructure is formed by mixing nano-Si_3N_4 particles. The crack trajectories exhibit crack deflection, rod-like grain bridging and pull-out, resulting in reinforcing and toughening.