氩弧熔覆(WC+SiC)/Ni基复合涂层组织及性能研究

Microstructure and properties of(WC+SiC)/Ni composite coating by argon arc cladding

以WC、SiC和Ni60A粉为原料,采用氩弧熔覆技术在Q345钢基体表面制备出WC+γ-Ni5Si2增强Ni基复合涂层。利用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计和滑动磨损试验机对复合涂层的显微组织、相构成、硬度及耐磨性进行了研究。结果表明:熔覆层相构成为WC、γ-Ni5Si2和γ-Ni,WC以颗粒状析出,由于氩弧熔覆时加热温度高,导致SiC分解,使Si与Ni在高温下形成了γ-Ni5Si2;熔覆层与基体呈冶金结合,无裂纹、气孔等缺陷;涂层最高硬度可达1200 HV0.2,是基体金属的4倍以上;在室温干滑动磨损试验条件下具有优异的耐磨损性能,耐磨性比基体提高了11倍。

Ni-based composite coating reinforced by WC＋γ-Ni5Si2 was prepared on the surface of Q345 steel by means of argon arc cladding technique with the pre-alloyed powder of WC,SiC and Ni60A.The microstructure,microhardness,phase composition and wear resistance were investigated using SEM,XRD,micro-hardness tester and slide wear tester.The results show that the main phases of the coating are WC,γ-Ni5Si2 and γ-Ni.Because of the high temperature,the SiC particles are resolved,and the new phase γ-Ni5Si2 is formed.The bonding between the coating and Q345 steel substrate is metallurgical,continuous and almost defect-free and the particles are dispersively distributed in the clad coating.The maximum hardness of the coating is 1200 HV0.2 which is more than 4 times compared with the Q345 steel,and the wear resistance of the coating is about 11 times higher than that of Q345 steel substrate.