Laser cladding Ni-based WC/MoS2 composite coatings: Particle competition mechanism and tribological performance
Kepeng Huang, Changjiang Zheng, Zexi Chen, Dayou Wu, Xuemei Yi
Abstract
• WC remains disadvantaged in terms of heat competition in the molten pool Compared with MoS 2 . • MoS 2 thermal decomposition alters M x C y carbides, inhibiting WC damage and reducing carbide content. • Cr x S y on the coating surface forms a stable, continuous lubricating film. • The coating achieves an optimal balance between wear resistance and lubrication. To develop a highly wear-resistant coating with self-lubricating characteristics, this study reports the use of laser cladding to fabricate WC/MoS 2 composite coatings on the surface of 65Mn steel plates. Here, we investigated the effects of different laser powers and MoS 2 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/MoS 2 composite coatings. The results show that compared with MoS 2 , WC remains disadvantaged in terms of heat competition in the molten pool. However, during MoS 2 thermal decomposition, the free Cr atoms in the pool are also captured, not only changing the type and morphology of the M x C y carbides and inhibiting WC heat damage but also resulting in a decreased content of M x C y carbides within the coating. When a significant amount of Cr x S y gathers on the coating surface, a stable and continuous lubricating film is formed, allowing the coating to balance the wear resistance with lubrication.