摘要
本文对电熔莫来石为基体制备的20vol.％SiC^w/ZTM复合材料的高温稳定性及其微观结构的变化进行了研究。通过试样室温电阻率和相对增重量的测定,证实了经高温空气中热处理后,材料中的SiC晶须将发生这—定程度的氧化,但材料的力学性能没有发生明显的变化。对试样的断口观察及X射线衍射分析发现,经1100℃、100h热处理后,试样表层中形成了厚度约40μm的氧化层,经初步鉴定该氧化层中生成了一种低熔化合物NaAlSi_3O_3,即钠长石,致使氧化层微观结构发生了明显变化,对抑制材料内部SiC晶须进一步氧化和钝化表面裂纹起到了一定的促进作用。
The high-temperature stability and the changes in microstructures of ZTM-20vol.% SiC_w composites were studied. Experimental results show that the effect of short-time heat treatment at high temperature in air on the mechanical properties of the composites is negligible, although the fact that the oxidization of the SiC whiskers occurred during the heat treatment is verified by the measurement of resistivity of the samples at room temperature. However, when aging the composites at 1100℃ for 100h in air, a compound with low melting point, i.e., NaAlSi_3O_3, appears in the surface layer of the samples, which results in obvious changes in microstructure between the interior and the oxidation layer of the heat-treated samples. The cause for the formation of the compound is believed to be related to the oxidization of SiC whiskers and the impurities in the ZTM matrix.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
1992年第3期218-222,共5页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金
关键词
莫来石
陶瓷
复合材料
碳化硅
晶须
silicon carbide whiskers
ZTM ceramics
composites
