Diffusion Phenomenon of Dysprosium Element during Electro-deposition Process on the Bonded Nd2Fe14B Magnet

Abstract A novel coating phenomenon and the outward diffusion of dysprosium (Dy) element occurred during Ni coating process on the bonded Nd 2 Fe 14 B magnet were investigated. The Dy-diffusion into the Nd 2 Fe 14 B was indicated due to the existence of dense (Nd, Dy) 2 Fe 14 B area in the region near of Ni layer. Energy dispersive analyzer (EDS) element mapping confirms that the three regions, i.e., Ni, (Nd,Dy) 2 Fe 14 B and Nd 2 Fe 14 B layer, were detected. The increase of (Nd,Dy) 2 Fe 14 B layer thickness influenced the magnetic properties of the sample, i.e. the increase of coercivity (H cj ) (from 7.34 to 8.7 kOe) and remanence (B r ) (from 2.62 to 4.06 kG).