Enhancing the magnetic properties and corrosion resistance of sintered NdFeB magnets by diffusion process

Abstract

Low melting point Ce-Al-Cu alloy was employed as the grain boundary diffusion source to prepare the NdFeB sintered magnets. Compared to the original Nd-Fe-B magnet, the coercivity Hcj can get 36.7 % increments for the Ce-Al-Cu diffused magnet. Meanwhile, the microstructure of the diffused magnet has been refined with the grain size of 10~20 μm and the corrosion potential Ecorr is increased to-0.68 V. Further investigation of mass loss of magnets in hot/humid atmosphere demonstrates that the addition of low melting point alloys can improve the corrosion resistance of NdFeB sintered magnets.