Influence of WC Content on Microstructure and Properties of WC/15-5PH Steel Composite Coating by Laser Cladding

15-5PH stainless steel coatings with WC mass fractions of 0, 10%, 20%, and 30% were prepared on the surface of Q235 steel by laser cladding. The microstructure, microhardness, wear resistance, and corrosion resistance of the coatings were studied. The results show that the 15-5PH stainless steel coating without WC was mainly composed of α-Fe, martensite, and Fe-Cr; the WC/15-5PH stainless steel composite coating with WC mass fraction of 10% was mainly composed of α-Fe, martensite, Fe-Cr, （Fe, Ni）, Cr₇C₃, Cr₂₃C₆, and WC. As the WC content further increased, a new phase W₂C appeared in the coating. With the increase of WC content, the number of columnar crystals in the coating decreased, the number of equiaxed crystals increased, the grains became significantly finer, and the number of undecomposed WC and newly generated W₂C, Cr₇C₃, and Cr₂₃C₆ carbide particles in the coating increased. With the increase of WC content, the microhardness of the coating increased, and the friction coefficient and wear rate decreased. The coating with WC mass fraction of 30% had the highest hardness of 539 HV, which was approximately 41% higher than that of the 15-5PH stainless steel coating; the friction coefficient and wear rate were the lowest, being 0.423 6 and 1.01×10⁻⁵ mm³·N⁻¹·m⁻¹, respectively, which were approximately 18% and 73% lower than those of the 15-5PH stainless steel coating. The main wear mechanism of the coating with WC mass fraction of 30% was oxidation wear, adhesion wear, and a small amount of abrasive wear. Compared to the substrate, the self-corrosion potential of the coating was more positive, the self-corrosion current density was smaller, the capacitive arc radius was larger, and the corrosion resistance was better than that of the substrate. With the increase of WC content, the self-corrosion current of the coating increased, the capacitive arc radius decreased, and the corrosion resistance decreased. The self-corrosion current of the 15-5PH stainless steel coating without WC was the smallest, being 2.64×10⁻⁶ A·cm⁻², with a relatively positive self-corrosion potential of −0.451 V, and the largest capacitive arc radius, achieving the best corrosion resistance.