Effect of Heat Treatment on Microstructure and Performance of Nano-WC Particle-Strengthened Ni Composite Coatings by Electrobrush Plating

Electrobrush plating technology has been widely used in surface remanufacturing and reinforcement and could be used to repair and reconstruct waste machinery and other products. In this paper, the effect of heat treatment on microstructure, wear resistance and thermal shock resistance of nano-WC particle-strengthened Ni composite electrobrush plating coatings was investigated using phase analysis, morphological observation, microhardness testing and coating lifetime evaluation. After heat treatment at 550°C, the cauliflower structure became more compact and the interface between coating and substrate was strengthened due to element diffusion, which led to an increase in the microhardness and coating lifetime. As the heating temperature increased, the microstructure of the coatings and substrate grew abnormally, which resulted in degradation of the coating properties. The extension of the thermal shock lifetime of the coatings after heat treatment contributed to microstructure improvement, element diffusion and new phase formation, which prolonged the times for crack initiation and propagation.