硅酸盐学报

用SEM和XRD等方法研究了Nicalon SiC束纤维强化7740硅硼酸盐玻璃和Nicalon SiC强化LAS玻璃陶瓷等三种复合材料的显微结构和在800—1100℃空气和氩气中热暴露后的界面特征。发现在复合材料中存在着无玻璃区、无纤维区、孔隙和未完全固结等制造缺陷。在高温下热暴露时,无玻璃区中的纤维和未固结区的玻璃粉会发生重烧结现象。同时发现SiC/LAS复合材料在高于800℃空气或氩气中热暴露后,基体和纤维界面开始形成较大的孔洞。随着温度的升高,孔洞数量增多,最后孔洞将纤维包围,基体和纤维分离,材料形成裂纹。同时发现,在界面靠玻璃一侧形成一低熔点玻璃相。本文对热暴露前后的相结构也进行了分析。

The microstructure and interface characteristics or Nicaion SiC yarn reinforced 7740 glass and Nicalon SiC yarn reinforced LAS glass-ceramics have been studied by means of SEM and XRD before and after exposure to the temperature ranging from 800 to 1100℃ for 48h. It is discovered that there are some defects in the manufacture, such as those in the non-glass area, non-fibre area, pores and ncomplete eonsolidation in composites. Resintering will occur in the non-glass area and incomplete consolidation area atahigher exposure temperature. It is also observed that some larger pores on the side of glass close to the fibre-matrix interface are first formed when SiC/LAS composite is exposed both in argon atmosphere and in air at 800℃. The amount of pores Increases with the exposure temperature, and finaly, each fibre is surrounded by the pores and separated from the matrix. Then, some short cracks join together formimg a longer crack passing through the whole sample of composite. A lower melting point glass which is also on the side of glass close to glass-fibre interface is also formed at a higher exposure temperature. The phases of composites before and after exposure to heat were also examined in the present study.