Abstract：Grain boundary diffusion is a technique in which diffusion source enters NdFeB magnets along the grain boundaries by heat treatment to improve the coercivity. The technical process is simple, low cost and the usage amount of heavy rare earth is small. In addition, the remanence and the maximum magnetic energy product of the magnet can be kept basically unchanged. As a result, grain boundary diffusion has a significant cost advantage for manufacturing small-sized high coercivity magnets. The research results at home and abroad were summarized. The principle of coercivity enhancement and anisotropic diffusion mechanism were introduced. The influence of diffusion process and diffusion source on magnet coercivity enhancement was discussed in detail. The development trend of grain boundary diffusion was also prospected.
2019, Vol. 29 
