Tribological properties and wear behavior of laser cladded Ni-WSe₂ composite coatings under dry sliding

Inconel 625 is widely used in aerospace, marine, and energy systems, but its high friction and insufficient wear resistance restrict service performance under severe sliding conditions. In this study, Ni-WSe₂ self-lubricating composite coatings were fabricated on Inconel 625 using laser cladding at 1000 W, 9 mm/s. The effects of WSe₂ content (0–15 wt%) on coating microstructure, hardness, friction, wear, and corrosion behavior were investigated. The results showed that appropriate WSe₂ addition refined the Ni-based matrix and promoted a uniform distribution of the lubricating phase, leading to increased hardness and improved sliding performance. Among all coatings, the 8 wt% WSe₂ coating exhibited the most favorable overall performance under the present testing conditions, with a maximum hardness of 484.6 HV, a low coefficient of friction of 0.247, the lowest wear volume of 0.08956 mm³, and the lowest wear rate of 2.30 × 10⁻⁵ mm⁻³.N⁻¹.m⁻¹, corresponding to an approximately 77.2% reduction compared with the 0 wt% WSe₂ coating. In addition, the optimized coating exhibited improved corrosion resistance, with a corrosion current density of 3.06 × 10⁻¹⁰ A.cm⁻². The improved performance is mainly attributed to the synergistic effects of microstructural refinement, enhanced coating integrity, optimized WSe₂-related phase distribution, and the formation of a WSe₂-derived lubricating layer during sliding, as supported by SEM-EDS and XPS analyses of the worn surface.