狭缝式化学气相沉积制备SiC涂层及其抗氧化性能研究

The preparation of SiC coating by slit chemical vapor desperation and its oxidation resistance

为了改善SiC涂层试样的均匀性,同时提高制备效率,利用石墨材料为沉积基体,通过狭缝式化学气相沉积法制备SiC涂层,同时分析并研究了SiC涂层的微观结构和抗氧化性能.研究结果表明:与普通化学气相沉积工艺相比,狭缝式化学气相沉积工艺沉积速率更大,沉积1 h后涂层厚度为17.3μm;狭缝式化学气相沉积工艺制备的SiC涂层晶粒更细,涂层均致密无缺陷,与基体相容性较好.狭缝式化学气相沉积的SiC涂层在1500℃时下具有较好的氧化防护能力,在静态空气中恒温氧化24 h后,氧化失重仅为4.01 mg/cm^2.狭缝式化学气相沉积的SiC涂层表面裂纹的尺寸很小,在氧化过程中更容易被氧化产生的SiO2玻璃态物质封填,而发生自愈合效应,从而使涂层具有良好抗氧化性能.

In order to improve the uniformity of the coating and raise the efficiency of the fabrication, the SiC coating was prepared on the surface of the graphite substrate by slit chemical vapor deposition. Microstructure and oxidation resistance of the SiC coating were investigated. In comparison with the common chemical vapor deposition, the slit chemical vapor deposition exhibits a higher deposition velocity, with a thickness of 17. 3 μm for 1 h. The SiC coating obtained is composed of smaller SiC grains and dense without defects. The coating shows good compatibility with substrate and good oxidation resistance. After oxidation at 1000℃ in static air, the weight loss of the slit chemical vapor deposition SiC coating sample is only 4. 01 mg/ cm^2. Good oxidation resistance contributes to the small size of the cracks in the coating and the self- healing of the glassy SiO2 oxidized from SiC.