Diffusion temperature dependent microstructure and magnetic properties of TbHx grain boundary diffused Nd–Fe–B magnets

Commercial N50 sintered Nd–Fe–B magnets were grain boundary diffusion (GBD) processed with TbHx powders. The diffusion temperature and time dependent microstructure and magnetic properties of the GBD processed magnets were investigated. High remanence and coercivity were obtained when the magnet was GBD processed at 875 °C for 14 h; the coercivity of the magnet increased from 12.57 kOe to 22.65 kOe. The relationships between microstructure and coercivity, remanence, and thermal stability of the GBD processed magnets were analyzed and discussed.