Carbon Nanotubes-Titanium Diboride/Copper (CNTs-TiB 2 /Cu) Laser Cladding Layer with Enhanced Tribo-Electrical Property on Wind Turbine Pitch Slip Ring

Wind turbine pitch slip ring requires excellent tribo-electrical properties, including low friction and wear, high current transmission efficiency, low power loss and contact resistance. To improve the tribo-electrical property, a CNTs-TiB2/Cu coating was prepared on slip ring surface by laser cladding. Microstructure, dilution rate, microhardness, tribo-electrical property and power transmission property of cladding layer were analyzed. Optimal metallurgical bonding was achieved at a laser power of 900 W, resulting in a dilution rate of 14.5%. Elemental Ti diffused from the substrate into the coating, forming a hard TiC phase that significantly improved both friction reduction and wear resistance. Additionally, the formation of Cu3Ti increased the electrical conductivity of the cladding layer. The contact resistance was reduced by 30% to below 0.06 Ω, while the current transmission efficiency improved by 25%, exceeding 90%.