Study On Modified NdFeB Permanent Magnetic Powder

This thesis describes electrodeposited nano-layer on NdFeB magnetic powders by the barrel plating DC electroplating method. Fe, Cu, Ni, Zn, Fe/ Ni and Zn /Ni nano-layer were fabricated. Research results indicated that the corrosion resistance and practicable properties of Neodymium-iron-boron magnetic powders were improved .The electrode potential, resistively ratio and magnetism of the bounded NdFeB permanent magnets that were modified were tested in the research.The electrode potential of the NdFeB magnetic powders and the plating was measured, the correlation between the electrode potential and corrosion resistance of NdFeB magnetic powders was discussed. The electrode potential of zinc was less than that of NdFeB magnetic powders. NdFeB magnetic powders were protected because Zinc had been the anode through the electrochemistry corrosion. Nikel plating on NdFeB permanent magnets was generally adopted.The mixed resistively ratio of the bounded NdFeB magnets and the plating was analyzed. The results indicated that the resistively ratio of the NdFeB magnetic powders cladded by the Zn/Ni was highly larger than that of non- cladding NdFeB magnetic powders. On the contrary, the resistively ratio of the NdFeB permanent magnetic powders cladded by copper was lowest. Because the copper resistively ratio is low, it is a good conductor. Electrodeposited nano-layer plating on the surface of NdFeB magnetic powders may be able to improve on electricity capability of the bounded NdFeB magnets.According to study on magnetic parameters of the bounded NdFeB magnets: coercive force(Hc), residual magnetism intensity (Br), (BH)max .the residual magnetism intensity (Br) and (BH)max of the bounded NdFeB magnets have not been evidently changed between that of cladded and non- cladded NdFeB magnetic powders. While the coercive force(Hc)of the Zn/Ni cladding bounded NdFeB magnets is lower.