Tribology Property of Laser Cladding Crack Free Ni/WC Composite Coating

Abstract

In order to improve wear resistance, the Ni/WC composite coating was prepared on NAK80 mold steel surface by laser cladding technology. Phase and microstructure had been investigated by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Dry sliding tribological properties at room temperature of the coating had been researched by ball-on-disc wear tests. Results indicated that phase constituents of the coating were mainly composed of WC, W₂C, Cr₂₃C₆, NiCr, CrB₂ and γ-Ni, etc. There was a chemical metallurgical bonding between the coating and the steel substrate. Higher wear resistance of NAK80 mold steel was achieved after cladded by the Ni/WC composite coating, which was mainly related to dendrite phases Cr₂₃C₆ and hard phases WC, W₂C dispersing in the coating.