Electroplating of sintered Neodymium magnet include zinc plating, nickel plating, tin plating, and other precious metal plating, where only zinc plating and nickel plating can be directly deposited on the magnet surface, thereby, zinc plating and Ni-Cu-Ni plating has always been the mainstream surface treatment technology for sintered Neodymium magnet. The standard electrode potential of zinc is -0.76V, then zinc plating layer is generally served as the sacrificial anode to steel workpiece. However, NdFeB alloy exhibits relatively higher chemical activity and zinc plating layer unable to embody anodic protection, therefore, protection of Neodymium magnet is primarily relying on the dense passivation film on zinc plating. Zinc plated Neodymium magnet can be classified to blue-white BW zinc plated Neodymium magnet and color zinc plated Neodymium magnet according to the passivation effect. BW zinc plating is the secondly commonly used surface treatment technology for the sintered Neodymium magnet. It should be noted that corrosion resistance of BW zinc plated Neodymium magnet is not as good as color zinc plated Neodymium magnet.
