Corrosion Protection of NdFeB Magnets with Electroplating Zn-Ni Alloys


H.Zhang1,2,Y.W.Song1,J.Z.Li1,H.X.Yang1,Z.L.Song1 1Ningbo Institute of Material Technology and Engineering,Chinese Academy of Sciences,Ningbo,315040,China 2 Institute of Solid State Physics,Chinese Academy of Sciences,Hefei,230001,China


NdFeB magnets were highly susceptible to corrosion in various environments.Protective Zn-Ni coatings electrodeposited on NdFeB permanent magnets from weak acid solutions were investigated in this paper.The influences of the main electroplating technological parameters including current density,bath pH,bath temperature and the [Ni]/[Zn] concentration ratio on the structure and chemical composition of Zn-Ni alloys coatings were studied.The optimum protective ability of Zn-Ni coatings to the NdFeB magnets were obtained with the Ni content up to 13 %,which depend on bath composition and operating conditions.The corrosion resistance properties were evaluated by whole-immersion and electro