CVD-SiC涂层的C/C-SiC复合材料的抗烧蚀性能

Anti-Ablative Preformances of CVD-SiC Coated C/C-SiC Composites

采用CVD法,1 050℃在三维针刺C/C-SiC复合材料表面制备SiC涂层,研究稀释气体与载气流量比分别为4∶1和2∶1制备条件下涂层的晶体结构、表面和断面的微观形貌,对比了涂层前后C/C-SiC复合材料的抗烧蚀性能。结果表明:稀释气体流量降低其制备的SiC涂层更加平整致密,与基体结合程度更好,沉积产物均为单一的β-SiC结晶相。在600 s的氧化烧蚀下,两种流量比条件下制备CVD-SiC涂层的C/C-SiC复合材料的线烧蚀率比未涂层的分别降低34%和50%,质量烧蚀率分别降低70%和75%,抗氧化烧蚀性能明显提高。

SiC coatings on the surface of the three dimensional needled carbon/carbon and silicon carbide （C/C -SIC） composites were prepared by chemical vapor deposition （CVD） at 1 050℃. The coatings are prepared by two kinds of experimental conditions which the flow ratio of diluting gas to carrier gas are 4：1 and 2：1. The crystalline structure and the surface and cross section micromorphologies of the coatings are analyzed by X-ray diffraction and scanning electronic microscopy. The oxidation and ablation performance are compared between uncoated and coated C/C-SiC composites. The results show that the deposited coatings mainly consist of β-SIC. The surface of coating prepared with reducing the flow of diluting gas is smooth and dense, and also strongly bonded with the substrate. As to the coated C/C-SiC composites, the linear ablation rate is reduced by 34% and 50% , and the mass ablation rate re- duced by 70% and 75% , compared to that of the uncoated C/C-SiC composites prepared with two kinds of flow rati- os, respectively, and the coatings show excellent antioxidation and anti-ablative performances.