Laser cladding Ni60 @ WC/ Cu encapsulated Rough MoS2 Self-Lubricating Wear Resistant Composite Coating and Ultrasound-assisted Optimization

This research aims to broaden the scope of self-lubricating wear-resistant coatings for applications in diverse industries such as automotive, metallurgy, power, and aerospace. Employing laser cladding technology, we successfully fabricated high-performance self-lubricating ceramic composite coatings. A comprehensive investigation was conducted to understand the inhibitory effect of Cu on the thermal decomposition of MoS₂, and the study systematically explored the relationship between powder composition, coating structure, and organizational properties. The mechanisms behind friction reduction and wear resistance were unveiled, shedding light on the formation of the MoS₂ self-lubricating protective film. Research findings reveal that during the laser cladding process, Cu and Ni undergo solid solution, resulting in the formation of the Cu-Ni alloy phase and crystal refinement. The MoS₂ aggregation area exhibits a fine dendritic structure, while the dispersion area showcases coarse dendritic and cellular crystals. The addition of Cu and MoS₂ influences the content of the M_xC_y phase and the thermal decomposition of MoS₂. The incorporation of Cu increases the average coating hardness, whereas MoS₂ addition decreases it; nevertheless, the Cu/MoS₂ coating hardness is enhanced by at least 6.4%. Cu significantly improves the coating's wear resistance, with a relatively smaller impact on friction reduction. MoS₂ functions as a friction-reducing phase during wear, effectively preventing the peeling of hard phases and reducing the friction coefficient. Cu is uniformly distributed in the coating, experiencing solid solution strengthening, reducing adhesive region areas, and minimizing wear debris generation. MoS₂, although unevenly distributed, forms intermittent lubricating films on the surface. The lubricating film of the Cu/MoS₂ coating remains stable, preventing mutual contact of the friction surface and concurrently reducing the friction coefficient and wear amount. While the study successfully prepared a self-lubricating ceramic coating with excellent wear resistance, some surface quality defects persist. Further optimization of the preparation method was achieved through ultrasound-assisted technology.