粉料粒度对氮化硅陶瓷性能的影响

Effect of Starting Particle Size on Properties of Liquid-phase Sintered Si_3N_4 Ceramics

用球磨的方式将平均粒径为6.46μm的β-氮化硅原料粉细化为不同粒度的亚微米级起始粉料,加入适宜的添加剂,以无压液相烧结的方法研究起始粉料粒度对氮化硅陶瓷的强度、硬度等机械性能的影响。用扫描电镜、X射线衍射等方法测试分析试样的显微结构、相组成等。结果表明,试样密度、强度、硬度等均随起始粉料粒度的减小而增大;试样显微结构显示了烧结体晶粒尺寸随起始粉料粒度的减小而减小,且粒度小的试样烧结的晶粒均匀、致密;烧结后试样的物相主要是β-氮化硅和少量黄长石,粉料的粒度对烧结后样品的物相没有影响。

The effect of starting particle size on the mechanical properties of liquid-phase sintered Si3N4 ceramics was investigated using mill-refined Si3N4 powders and the appropriate additives. The microstructure and phase composition were determined by using SEM and XRD. The results indicate that the density, strength and hardness of all of Si3N4 ceramic are improved with decrease of Si3N4 particle size. The size of Si3N4 crystals grains is uniform and compact with the smaller size of starting particles. The phase composition of resultant SigN4 ceramics is not changed with the particle size and only contains β-Si3N4 and a little ofmelilite.