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分别采用包埋法、料浆法在碳/碳(C/C)复合材料表面制备了碳化硅(SiC)内涂层、W-Al-Si合金外涂层,借助XRD和SEM分析了所得涂层的物相组成和微观结构,并测试了带有单一SiC涂层、SiC/W-Al-Si双涂层碳/碳复合材料试样在1500℃静态空气中的抗氧化性能。结果表明:富Si的SiC内涂层结构疏松,仅能为碳/碳基体提供数小时的防氧化保护;W-Al-Si合金外涂层主要由WSi2和W(Si,Al)2两相组成;SiC/W-Al-Si双涂层厚度约为100μm,其抗氧化性能明显优于单一SiC涂层,氧化19 h后涂层试样的质量损失未超过5%;有望进一步通过优化W-Al-Si外涂层料浆比例,避免因为与SiC内涂层热膨胀不匹配而产生透性裂纹,从而发挥出超过19 h后SiC/W-Al-Si双涂层的氧化防护潜力。
Silicon carbide (SiC) undercoating and W-Al-Si alloy overcoating were prepared on the surface of carbon / carbon composite by embedding method and slurry method respectively. The results of XRD and SEM were also analyzed. The phase composition and microstructure of the SiC / W-Al-Si double coated carbon / carbon composites were tested in static air at 1500 ℃ with a single SiC coating. The results show that the Si-rich SiC inner coating has a loose structure and can only provide several hours of anti-oxidation protection for the carbon / carbon matrix. The W-Al-Si alloy outer coating mainly consists of WSi2 and W (Si, Al) 2 two phases , The thickness of the SiC / W-Al-Si double coating is about 100μm, its oxidation resistance is obviously better than the single SiC coating, and the mass loss of the coating sample does not exceed 5% after oxidation for 19 h. It is expected to further optimize the W -Al-Si overcoating slurry ratio to avoid permeability cracking due to mismatch with the thermal expansion of the SiC inner coating, thereby exerting the oxidation protection potential of the SiC / W-Al-Si double coating after more than 19 h.