(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 采用化学气相反应法在C/C复合材料表面制备抗氧化SiC涂层，借助X射线衍射仪、扫描电镜及能谱等分析手段，研究涂层的结构；通过氧乙炔焰烧蚀试验考察SiC涂层对C/C复合材料高温耐烧蚀性能影响。结果表明：SiC涂层可明显提高C/C复合材料的高温短时耐烧蚀性能，经过20 s的高温氧乙炔焰烧蚀后，C/C复合材料试样的线烧蚀率和质量烧蚀率分别为13 μm/s和6.6 mg/s，SiC涂层试样的线烧蚀率和质量烧蚀率分别为22 μm/s和0.5 mg/s；在烧蚀中心区，涂层试样的烧蚀以升华分解为主，同时还伴有氧化烧蚀和微区机械剥蚀；在烧蚀过渡区，涂层的烧蚀机制以热氧化和燃气冲刷为主；而在烧蚀边缘区，涂层的烧蚀则主要表现为弱氧化烧蚀。
关键字: C/C复合材料；抗氧化涂层；SiC；氧乙炔焰烧蚀
C/C composites under oxyacetylene torch flame
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The anti-oxidation SiC coatings were prepared on C/C composites by the chemical vapor reaction (CVR) method. The structure of the coatings was studied by XRD, SEM and EDS analysis, and the effect of SiC coatings on ablation resistance of C/C composites was investigated by oxyacetylene torch flame test. The results show that the prepared SiC coatings can effectively improve the ablation resistance of C/C composites in short time ablation. After 20s ablation by oxyacetylene flame, the linear ablation rate and mass ablation rate of C/C composites are 13 μm/s and 6.6 mg/s, respectively while those of SiC coated C/C composites are 22 μm/s and 0.5 mg/s, respectively. In the ablation center, the ablation mechanism of the coated sample is sublimation and decomposition, combined with thermo-oxidation and mechanical denudation. In the transitional field, the ablation mechanism of the coating is controlled by thermo-oxidation and scouring. And in the ablation rim, the coating exhibits slight oxidation behavior.
Key words: C/C composites; anti-oxidation coating; SiC; oxyacetylene torch flame ablation
