Tribo-electrical performance of TiB2/Cu laser cladding-remelting layer under high-current sliding contact

Slip rings are prone to wear under high-current conditions, resulting in wind turbine failures. To enhance durability, TiB₂/Cu coatings were fabricated on the surface of slip rings using laser cladding and remelting technologies. The tribo-electrical performance of coatings under high-current sliding contact was investigated and the effect of laser cladding-remelting on the tribological and electrical properties of coatings was revealed. The results demonstrate that, compared to the cladding layer, the dilution rate, conductivity, and hardness of remelting layer were increased by 11 %, 2 %, 12 % respectively, and the porosity, longitudinal and transverse residual stress were reduced by 70 %, 33 %, 61 % respectively. At a current of 50 A, the service life of remelting layer was extended, and wear loss was significantly reduced while maintaining a high current-carrying efficiency of 95.2 %. Additionally, due to a new hard phase TiC generated in laser process, as well as the increased melting point of coating, the hardness, wear resistance and softening resistance of the TiB₂/Cu layer were improved.