助烧剂对热压Si_3N_4基陶瓷组织结构的影响

Effect of Sintering Addtives on Microstructure of Hot-pressed,Si_3N_4 Ceramics

用XRD，SEM，TEM分析了用Y2O3＋Al2O3及Y2O3＋AlN做动烧剂的两种热压Si_3N_4某陶瓷的组织结构，用EDXA分析了Si，Al，Y等元素的含量。结果表明，两种SiN4都是由长柱状β相组成;用Y2O3＋Al2O3做助烧剂的Si3N4晶粒大且长径比高，晶界相较多，其β相中无Al的固溶；用Y2O3＋AlN做助烧剂的Si_3N_4的β相中有Al的固溶，且小晶粒中含量高，已形成β－Sialon.

The microstructure of hot-pressed Si3N4 ceradrics with Y2O3 + Al2O3 or Y2O,3+ AlN asadditive has been investigated by means of XRD, SEM and TEM and the contents of Si,Al andY in Si3N4 ceramics are measured by EDXA. Experimental results show that two kinds of Si3N4are formed by elongated β-phases.The size of β-phase grains in Si3N4 with Y2O3+A12O3 asadditive is bigger, and the content of non-crystallized intergranular phase is higher than thatwith Y2O3+AlN as additive.The results also show that Si3N4 with Y2O3+AlN contains Al inwhich the PSialon is formed, but Si3N4 with Y2O3+Al2O3 does not.It is also found that, in theSi3N4 with Y2O3+AlN as additive, the smaller grains has a relatively higher content of Al.