CVI法制备SiCp/SiC复合材料的氧化性能研究

对用CVI法制备的SiCp/SiC复合材料的氧化性能进行了研究。材料含有的气孔和破坏氧化膜连续性的杂质元素,为氧气扩散提供通道;氧化过程中形成的气孔,导致了新的自由表面的暴露和空气扩散通道,进而加剧氧化。在材料的高温氧化过程中,SiC的氧化生成SiO2膜导致试样质量增加,玻璃碳界面层的氧化生成CO的逸出导致试样质量损失。最后的质量变化是这两种综合作用的结果。在高温氧化过程中,材料的空隙增多,应力集中加强,界面层被破坏使SiCp/SiC复合材料的强度下降。

Oxidizing properties of SiCp/SiC composite manufactured by CVI

In this paper,the oxidizing properties of SiCp /SiC composite by Chemical Vapor Infiltration(CVI) were investigated.The impurities destroyed the continuity of the oxidizing film,which offered channels for the oxygen soaking into the composites as well as the holes of the composites.The holes which were formed during the oxidizing process make the oxidation worse.During the oxidizing process at high temperature,the SiC was oxidized and formed SiO2 film,which made the weight of the samples increase,whereas,the interface layer was oxidized and formed CO which induced the weight decreases.The final weight is the result of the above two kinds of functions.The bending strength of SiCp/SiC reduced after oxidization at high temperature.