Process and properties of Ni coating on NdFeB magnet by surface pulsed electrodeposition

Based on the current development needs of NdFeB industry and the problems faced by surface protection technology, pulse electrodeposition technology was introduced in this paper to improve the surface corrosion resistance of NdFeB magnets. Ni coatings with low defect rates and high surface comprehensive quality were obtained by optimizing processes such as duty cycle, frequency and current density. The corrosion potential of the coating increases from -894.36 mV to -680.0 mV, and the corrosion current density reaches 3.5×10^-6 A/cm², which effectively reduces the corrosion tendency and corrosion rate of the coating. Combined with the analysis of the surface microstructure of the coating, it is found that the concentration polarization can be reduced by the regulation of duty ratio and frequency, while the regulation of current density can improve the surface quality of the coating.