Y改性的MoSi2-MoBx复合涂层制备及氧化行为

Preparation and Oxidation Behavior of Y Modified MoSi2-MoBx Composite Coating

通过两步包埋法在钼表面制备了Y改性的MoSi2/MoBx复合涂层。采用SEM、EDS和XRD分析了渗剂中Y添加对渗B过程影响及Y改性的MoSi2/MoBx复合涂层的组织结构与氧化行为。结果表明：在渗B过程中,涂层表层的主要物相为β-MoB2;添加稀土Y能增强B元素的向内扩散,并起到催渗作用;Y改性的MoSi2/MoBx外层为固溶了部分MoB的MoSi2,内层为MoB与Mo2B混合相;在1150℃下循环氧化20h后,Y改性的MoSi2/MoBx复合涂层的外层生成了SiO2层,且MoSi2发生了扩散,生成了Mo5Si3,但MoBx层能有效阻止MoSi2的扩散。

Y modified MoSi2/MoB composite coating was prepared by two-step pack cementation methods on molybdenum surface. The effects of Y addition on the boronizing process and the microstructure and oxidation behavior of Y modified MoSi2/MoBx composite coatings were analyzed by SEM, EDS and XRD. The results show that the main phase of the coating is β-MoB2 during boronizing process, and the addition of rare earth Y can enhance the inward diffusion of B element and has catalytic effect. The outer layer of Y modified MoSi2/MoBx composite coating is MoSi2 with solid slution of part of MoB. The inner layer is MoB and Mo2B mixed phase. After cyclic oxidation at 1150 ℃ for 20 h, the outer layer of Y modified MoSi2/MoBx composite coating generates SiO2 layer and MoSi2 generates diffusion, then, M05Si3 appears, but MoBx layer can effectively prevent the diffusion of MoSi2.