Effect of optimized aging processing on properties of the sintered Dy-doped Nd-Fe-B permanent magnet

We investigate the effect of the optimized aging processing on magnetism and mechanical property of the sintered Dy-doped Nd-Fe-B permanent magnet. The experimental results show that the magnetism, especially intrinsic coercivity, of the optimized aged Dy-doped Nd-Fe-B magnet is more excellent than that of the sintered one, but the former's strength and hardness are lower than that of the latter. It was observed that the optimized aged Dy-doped Nd-Fe-B magnet have more uniform grain size, thinner (Nd, Dy)-rich boundary phase. By means of the EBSD technology, the number of larger angle grain boundaries in the optimized aged Dy-doped Nd-Fe-B magnet is more than that of the sintered one. The reasons for the increased intrinsic coercivity and decreased mechanical properties of the optimized aged Dy-doped Nd-Fe-B magnet are also discussed.