Electroplating mechanism of nanocrystalline NdFeB film

Nanocrystalline NdFeB film was fabricated onto the copper substrate through direct current electroplating method, and characterized by scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscope (EDS), vibrating sample magnetometer and potentiodynamic polarization techniques. The initial electroplating behavior was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Results revealed that the corrosion resistance of the NdFeB film was better than that of the traditional sintered NdFeB magnet. The depositing process of the NdFeB film followed the three-dimensional nucleation and subsequent grain growth mechanism, and was controlled by charger transfer. With the increase of the negative potential bias, the deposition mechanism of NdFeB film changed from heterogeneous to homogeneous nucleation/growth, which consequently resulted in the decrease of charge-transfer-resistance.