等离子弧喷焊颗粒增强铁基合金涂层组织的分析

采用等离子弧喷焊技术,利用后送粉装置在45钢表面制作了WC颗粒增强铁基合金复合涂层,并采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和能谱仪(EDS)分别对涂层组织结构及成分进行了分析.结果表明,WC颗粒主要分布在涂层顶部,在中部和底部有少量的WC,分布比较均匀;从涂层与基体的熔合区到涂层顶部分别出现了平面晶、胞状晶、树枝晶和等轴晶;涂层表面组织中化合物主要由WC,Fe23B6,Cr23C6,Cr7C3,W2B5,FeW2B2等组成;在喷焊过程中,WC发生了溶解,涂层顶部WC的溶解量比较大;从基体到涂层表面,硬度值基本呈上升趋势,最高达2 218 HV.

Analysis on microstructure of particles reinforced Fe-based layers by plasma spray welding

The WC reinforced Fe-based alloy composite coatings were prepared on the surface of 45 steel by back feeding equipment of plasma spray welding.Scanning electron microscopy(SEM), X-ray diffraction(XRD) and energy diffraction spectrum(EDS) were used to analyze the microstructures and compositions of the coatings.The results show that WC particles are mainly distributed on the top of the coating, and less in the middle and bottom of coating.There are planar crystal, celluler crystal, dendritic crystal and equiaxed crystal from the interface of coating/substrate to the top of the coating.The surface of the coatings has a microstructure consisting of WC, Fe₂₃B₆, Cr₂₃C₆, Cr₇C₃, SiC, W₂B₅ and FeW₂B₂.The WC particles have dissolution in the spraying process.The dissolution at the top of the coating is higher.The hardness increases from the matrix to the surface of coatings, which is up to 2218 HV.