金属钼表面Mo-C-N-Si涂层的制备及其高温氧化特性

在金属钼表面制备了Mo-C-N-Si涂层,研究了涂层在1600℃大气环境下的氧化特性,采用SEM和XRD分析了涂层的微观结构和物相组成。结果表明:Mo-C-N-Si涂层以MoSi2为主相,SiC和Si3N4为次相,存在Mo2C+MoxN中间层;由于扩散和氧化反应,涂层在氧化初期形成SiO2氧化膜层、MoSi2主体层、Mo5Si3层和Mo2C+MoxN层等四层结构,氧化后期转变为Mo2C+MoxN层和Mo3Si+Mo5Si3层的双层结构,导致涂层失效。由于C、N的引入,涂层抗热震性能良好。

Preparation of Mo-C-N-Si Coating on Mo Substrate and Its Oxidation Property at High Temperature

Mo-C-N-Si coating on Mo substrates was prepared. The oxidation property of the coating at 1600 oC in air was investigated. Microstructures and phase composition of the coatings were analyzed by means of SEM and XRD, respectively. Results show that Mo-C-N-Si coating consists of the MoSi2, SiC and Si3N4 phases. The middle layer of Mo2C+MoxN can be observed in the coating. Mo-C-N-Si coating becomes four layer structures, i.e. SiO2 oxidation layer, MoSi2 body layer, Mo5Si3 layer and Mo2C+MoxN layer at the initial stage of oxidation duet to the diffusion and oxidation. However, Mo-C-N-Si coating fails in the later stage, probably because it changes to double-layer structures of Mo2C+MoxN layer and Mo3Si+ Mo5Si3 layer. In addition, the thermal shock resistance of the coating is improved by the addition of the C and N elements.