反应烧结ZTM陶瓷显微结构分析及热处理对晶界玻璃相析晶的影响

SEM ANALYSES OF MICROSTRUCTURE AND EFFECT OF ANNEALING ON CRYSTALLIZATION OF BOUNDARY GLASS OF ZTM COMPOSITES OBTAINED BY REACTION-SINTER

本实验利用电子扫描电镜重点研究了以锆英石与氧化铝、A级铝矾土为原料反应烧结ZTM陶瓷的显微结构。分析表明 :在不同的液相条件下 ,莫来石的晶粒发育产生了三种完全不同的晶形 ;液相量越高 ,莫来石的针状发育越好。过量氧化铝的存在严重阻碍了残余晶界玻璃相的析晶。金属铝粉的添加容易引入热处理难以消除的贯通性气孔。这些气孔是影响反应烧结材料性能提高的重要因素。

In this paper,the characteristic of microstructures of different ZTM composites obtained by reaction-sinter was analyzed by means of the SEM images.The SEM images indicates three different types of mullite grains could be formed according to the content of glass and the excess Al 2O 3 content.The chemical analyses also showed the content of the residual glass played the important role in mullite grain growth.The crystallization of the residual glass was difficult for specimens with excess Al 2O 3.The anneal process,to some extent,could not erase some pores formed due to oxidization of aluminium powder.Pore was the most important factor for strength developing of the reaction sinter samples.