Anti-oxidation property of a multi-layer coating for carbon/carbon composites in a wind tunnel at 1500℃
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摘要: 为提高炭/炭（C/C）复合材料的抗高温燃气冲刷性能，分别采用包埋法、化学气相沉积法和料浆法在其表面制备了三层涂层。借助扫描电镜、电子能谱等测试手段对涂层试样的微观结构进行了分析，同时研究了涂层C/C复合材料在高温风洞环境中的抗冲刷性能，并分析了涂层在燃气冲刷环境下的失效原因。结果表明：三层涂层由MoSi2-SiC-Si多相内涂层、SiC中间层和玻璃外涂层构成，其厚度分别为80μm, 20μm和80μm。该复合涂层可在1500℃风洞环境下对C/C复合材料有效保护53h。涂层在高温风洞中防氧化失效是由于涂层在热冲击以及承受气流冲击的恶劣环境下开裂引起的。Abstract: To protect carbon/carbon (C/C) composites against oxidation at 1500℃ in a wind tunnel, a multi-layer coating was prepared on them by a combination of pack cementation, chemical vapor deposition and slurry coating. X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy were used to analyze the phase, microstructure and elemental distribution of the coating. Results show that a three-layer structure is formed including a multi-phase MoSi2-SiC-Si inner layer, a SiC middle layer and a borosilicate glass outer layer with thicknesses of about 80, 20 and 80μm, respectively. The three-layer coating can protect the C/C composites from failure at 1500℃ for 53 h in a wind tunnel. The cracking of the coating by thermal shock and gas-fired impact is the main cause for the failure of the coating.
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Key words:
- Carbon-carbon composites /
- Coating /
- Fracture
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