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以Y_2O_3粉和硅树脂配制成的浆料为原料,通过浸涂提拉法在C/SiC复合材料表面制备Y_2Si_2O_7涂层,研究Y_2Si_2O_7相的合成、涂层结构和氧化保护效果以及抗氧化机制。结果表明,质量比为54.2:45.8的Y_2O_3粉/硅树脂混合物先在800°C空气中裂解再在1400°C Ar惰性气氛下热处理,能够完全转化成Y_2Si_2O_7。Y_2Si_2O_7涂层致密度高且与基体结合紧密,在氧化过程中发生进一步致密化而呈现出优异的抗氧化性能,分别在1400、1500和1600°C氧化30 min后,复合材料的强度保留率达到130%~140%。此外,在1500°C下Y_2Si_2O_7涂层会与氧化铝支撑体之间发生反应,生成具有低共熔点的Y-Si-Al-O玻璃相。
Y_2Si_2O_7 coating was prepared on the surface of C / SiC composites by dip coating and pulling method. The effects of Y 2 Si 2 O 7 phase composition, coating structure, oxidation protection and anti-oxidation mechanism were studied. The results show that the Y 2 O 3 powder / silicone mixture with mass ratio of 54.2: 45.8 is first pyrolyzed in air at 800 ° C and then heat treated at 1400 ° C under Ar inert atmosphere, which can be completely transformed into Y_2Si_2O_7. Y_2Si_2O_7 coating has high density and close bond with the matrix, and further densification occurs during the oxidation process and exhibits excellent oxidation resistance. The strength retention rate of Y_2Si_2O_7 coating reaches the maximum at 1400, 1500 and 1600 ° C respectively for 30 min 130% ~ 140%. In addition, the Y_2Si_2O_7 coating reacts with the alumina support at 1500 ° C to form a Y-Si-Al-O glass phase with a low eutectic point.