Preparation and Characterization of Laser Clad NiCrBSi Coating Reinforced with WC

NiCrBSi coating reinforced with WC was prepared on the steel substrate surface of 42CrMo alloy structure based on coaxial powder-feeding laser cladding technology by using the YLS-6000 fiber laser. Phase composition, microstructure, microhardness and wear resistance of specimens were discussed by the X-ray diffractometer (XRD), scanning electron microscope (SEM), microhardness meter and ring-block friction wear testing machine. Results demonstrated that the composite coating is mainly composed of γ-Ni solid solution and WC, accompanied with phases like FeNi₃, B₂Co₃, CoC_x, FeCr_0.29Ni_0.16C_0.06, W₃C and Co₃W₃C₆. The top, middle and bottom of the cladding layer are occupied by tiny dendrites, coarse columnar dendrites and cellular crystals perpendicular to the interface. Moreover, good metallurgical bonding is formed between the coating and base. Hardness and wear resistance of the composite coating are far higher than those of the 42CrMo base. According to west test, the base presents typical adhesive wearing characteristics, while the composite coating mainly shows abrasive wearing performances. (paper)