Microstructure and Hardness of the Laser Cladding Ni-based Alloy Coating on the Surface of Cu

A Ni-based alloy coating was formed by high velocity air fuel (HVAF) spaying first on the surface of Cu-substrate and then irradiated by high power density laser.The cladding layer was characterized by OM,SEM,XRD and microhardness tester.The results show that an excellent laser cladding coating was obtained by HVAF with dense microstructure,crackfree and obviously reduced pores and inclusions.It was found that a W phase layer with high melting point and high density was formed at the bottom of the laser cladding coating,which increased the microhardness obviously.The metallurgical bonding layer with about 13 μm in thickness was found due to the Cu and Ni diffusion into each other between the coating and the substrate.The average microhardness of cladding layer was more than eight times to that of the Cu substrate.