C/C复合材料硅化物涂层形貌及结构

Morphology and structure of silicide coating on carbon-carbon composites

采用料浆烧结法在1 450℃温度下烧结制备了C/C复合材料硅化物高温抗氧化涂层,通过XRD和SEM分析涂层结构及相组成,并对涂层形成机理及涂层氧化前后的结构和形貌变化进行了研究。结果表明:在C/C复合材料表面生成了以MoSi2为主、含部分SiC的两相硅化物主体层,同时在主体层和基体间生成SiC过渡层,保证了涂层与基体的良好结合;涂层在1 500℃下氧化生成SiO2玻璃膜,阻挡了氧向基体内部的扩散;氧化过程中Si元素的扩散导致涂层内部微裂纹增多,同时SiC过渡层厚度增加。

The high-temperature oxidation-resistant silicide coating on carbon-carbon composites was prepared at 1 450 ℃ by slurry firing, the formation mechanism, morphology and structure of the coating were studied. The resuits indicate that the coating is biphase structure including MoSiz and SiC out layer and SiC inner layer on substrate, the SiOz glass layer formed on the surface of the coating during oxidation in air at 1 500 ℃ prevents oxygen from further diffusion; the diffusion of Si results in the increasing of microcracks in coating and the thickness of SiC layer.