超高速激光熔覆镍基WC涂层的显微结构与耐磨性能

Steel materials are highly sourced construction materials owing to their robust mechanical properties, and they are widely used in the construction industry for building bridges, tunnels, skyscrapers, towers, ship-metal parts, and other industrial metal applications. However, as steel has poor surface wear resistance, parts are susceptible to failure due to friction damage. To improve the surface wear resistance of steel materials, Ni-based WC coating was prepared by ultra-high-speed laser cladding. Using low-speed laser cladding as a reference, the surface morphology, microstructure, and wear resistance of ultra-high-speed laser cladding of Ni-based WC coatings were studied using SEM, EDS, and XRD, respectively. Experimental results revealed that the Ni-based WC coating prepared by ultra-high-speed laser cladding exhibited better surface quality compared with that prepared by low-speed laser cladding. Comparatively, ultra-high-speed laser cladding requires a smaller heat input and a faster cooling rate. However, the dilution rate of the coating is significantly reduced. In addition, ultra-high-speed laser cladding significantly reduces thermal damage in the WC coating; it inhibits the precipitation of carbides and formation of porosities and promotes the uniform distribution of the WC in the coating, thereby significantly reducing stress localization in the coating and also inhibits crack nucleation in the coating. Because of the reduction of porosities, cracks, and other surface defects in the coating and uniform distribution of WC particles, the Ni-based WC coating prepared by ultra-high-speed laser cladding possesses better wear resistance than that prepared by low-speed laser cladding, and the wear mechanism is abrasion.