熔盐法在石墨表面中温制备MoSi2-SiC复合涂层

摘要

The anti-oxidation coating of MoSi2-SiC on graphite surface was prepared by salt pack cementation. The microstructure and formation mechanism of the composite coating was studied by XRD, SEM and EDS analysis, and the anti-oxidation property of the coating was also investigated. The results show that the coating is composed of MoSi2 and SiC, with a small amount of unreacted Mo2C on the nearside of graphite. The coating is dense and combined with substrate tightly, covering the entire surface homogeneously and continuously. Thickness of the coating is about 60μm. The whole reactions are conducted in the range of mid-temperature (900~1 000℃), thus it will not produce significant thermal stress and perforate crack will not appear on the surface of the coating. Mass of the graphite samples with MoSi2-SiC coating oxidized in air for 100 h increases by 0.24%, proving that the coating has good antioxidant property.%采用熔盐法在石墨表面制备MoSi2-SiC复合涂层，利用X射线衍射分析﹑扫描电镜及能谱分析等手段对涂层的组织结构与形成机理进行研究，并考察涂层的高温抗氧化性能。结果表明：复合涂层由MoSi2和SiC两相组成，基体内部残留少量未完全硅化的Mo2C。涂层致密，与基体结合紧密，并且均匀连续的包覆整个样品表面，涂层厚度约为60μm。涂层制备在中温环境(900～1000℃)下进行，因而样品不会产生过大的热应力，可避免涂层表面出现贯穿性裂纹。该复合涂层样品在1500℃的静态空气中保温100 h之后，质量增加0.24%，证明涂层具有良好的抗氧化性能。