CVD-SiC涂层的C/C-SiC复合材料的抗烧蚀性能

摘要

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 reduced by 70％ and 75％,compared to that of the uncoated C/C-SiC composites prepared with two kinds of flow ratios,respectively,and the coatings show excellent antioxidation and anti-ablative performances.%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.