Microstructure evolution and wear resistance of Ni-coated WC composite coating fabricated by laser cladding

The distribution of WC particles in laser cladded composite coatings can significantly affect the wear resistance of the coatings under aggressive environments. Ni-coated WC composite coatings have been found in many industrial applications. In this study, Ni-coated WC powders are deposited on the surface of SS316L via laser cladding. The microstructure and phases distributions of the obtained coating are investigated with X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and scanning electron microscopy (SEM). The wear behavior and mechanisms of the coating are studied under dry sliding wear tests. The experimental results show that the partially dissolved WC particles uniformly distribute in the coating, and they are embedded in the eutectic structure matrix. Based on the EDS and XRD spectra, the carbides are confirmed to be WC and the eutectic structure matrix is the mixture of M23C6 and γ - (Ni, Fe). The dry sliding wear tests reveal that the wear of the coating is mainly characterized by plough wear and oxidization wear but also accompanied with abrasive wear. The composite coating exhibits much enhanced wear resistance and hardness compared to SS316L substrate.