Effect of WC content on microstructure, mechanical properties, and tribo-corrosion behavior of laser-cladded Ni40A/WC composite coatings on H13 steel

Abstract

Ni40A/WC composite coatings were fabricated on H13 steel substrates via laser cladding technology, and the influence of WC content on the microstructure, microhardness, wear resistance, and corrosion resistance of the coatings was systematically investigated. The results demonstrate that an optimal WC content results in a Ni40A/WC composite coating with a smooth surface and dense microstructure. The addition of WC significantly enhances the nucleation rate, promotes grain refinement, and alters the preferential orientation of grain growth as well as the texture formation. Furthermore, the decomposition of WC leads to the formation of a W₂C hard phase. With increasing WC content, the microhardness and wear resistance of the coatings are markedly improved. Specifically, the microhardness of coatings with 0 wt%, 15 wt%, 30 wt%, and 45 wt% WC content is 1.7, 1.98, 2.17, and 2.48 times higher than that of the H13 substrate, respectively. Correspondingly, the wear rate is reduced by 39.14 %, 56.55 %, 73.88 %, and 82.59 % compared to the H13 substrate. In the absence of WC, the wear mechanism is dominated by adhesive wear accompanied by minor delamination wear. However, the introduction of WC transforms the wear mechanism to abrasive wear. In terms of corrosion resistance, the composite coating exhibits enhanced performance only when the WC content is below 30 %, as indicated by a positive shift in the self-corrosion potential and a decreased corrosion rate relative to the H13 substrate.