The effects of parameters on the mechanical properties of Ni-based coatings prepared by automatic brush plating technology

The pure nickel coatings were prepared by using a newly developed automatic brush plating system. The microstructure of the coatings was characterized using SEM and the crystalline size of the coatings was determined by XRD based on Scherrer's formula. The hardness, elastic modulus and wear performance of the coatings were also investigated. The results showed that the microstructure and performance of the coatings were greatly affected by the processing parameters such as current density, relative motion and contact pressure. Pure nickel coatings prepared at lower current density possessed smoother, denser and more uniform microstructure, and exhibited higher microhardness, elastic modulus and better wear resistance. Pinholes were eliminated from the coatings when the relative speed exceeded a critical value. Coatings prepared at higher contact pressure were smoother and denser. However, high internal stress was generated and resulted in crack somewhere in the coating. The results presented here revealed that we can adjust the electrodepositon parameters properly to improve the mechanical and tribological properties of the coatings.