Laser cladding Ni-based WC/MoS2 composite coatings: Particle competition mechanism and tribological performance

To develop a highly wear-resistant coating with self-lubricating characteristics, this study reports the use of laser cladding to fabricate WC/MoS2 composite coatings on the surface of 65Mn steel plates. Here, we investigated the effects of different laser powers and MoS2 contents on the phase composition, phase distribution, microstructure, and friction/wear properties of the coatings, focusing on heat and element competition mechanisms, as well as the wear mechanism of the Ni-based WC/MoS2 composite coatings. The results show that compared with MoS2, WC remains disadvantaged in terms of heat competition in the molten pool. However, during MoS2 thermal decomposition, the free Cr atoms in the pool are also captured, not only changing the type and morphology of the MxCy carbides and inhibiting WC heat damage but also resulting in a decreased content of MxCy carbides within the coating. When a significant amount of CrxSy gathers on the coating surface, a stable and continuous lubricating film is formed, allowing the coating to balance the wear resistance with lubrication.