C/C复合材料防氧化涂层SiC/SiC-MoSi_2的制备与抗氧化性能

PREPARATION AND ANTI-OXIDATION PROPERTY OF SiC/SiC-MoSi_2 COATING ON C/C COMPOSITE

采用包埋法和涂刷法在C/C复合材料表面依次制备了SiC内涂层和SiC-MoSi_2外涂层,借助XRD与SEM对涂层的微观结构句进行了分析,研究了涂覆后的C/C复合材料在高温静态空气中的防氧化性能.结果表明:SiC/SiC-MoSi_2复合涂层有效缓解了MoSi_2与C/C热膨张不匹配问题,涂层无裂纹;复合涂层在900和1500℃静态空气环境下均可对C/C复合材料有效保护100 h以上;涂层的多层、多相结构以及在高温氧化后表面生成的SiO_2薄膜是其具有优异防氧化性能的原因.

To protect carbon/carbon （C/C） composites against oxidation at high temperature, SiC inner layer and SiC MoSi2 multi-layer outer coatings were prepared on the surface of C/C composites by a two-step technique of pack cementation and slurry coating. The microstructure of the as-received coating was analyzed by XRD and SEM. The oxidation behaviors of the coated samples at high temperatures in air were studied by isothermal oxidation tests. The results show that the as-received multi-layer SiC/SiC-MoSi2 coating posseses a crack free structure and excellent oxidation resistance, which could protect C/C composites from oxidation in air for more than 110 h at 1500 ℃ and for more than 100 h at 900 ℃. Excellent anti-oxidation ability of the SiC/SiC-MoSi2 coating is attributed to its multi-layer and multi-phase structure and the formation of protective SiO2 film on its surface during oxidizing.