Effect of Tb-Fe diffusion on magnetic properties and thermal stability of hot-deformed magnets

Hot-deformed Nd-Fe-B magnets co-doped with and without Tb-Fe addition are prepared to study the effect of Tb-Fe particles on the magnetic properties and thermal stability. With the addition of 2 wt. % Tb-Fe particles, the coercivity increases by 28.7%, while the remanence decreases by only 3.6%. It is observed that Tb atoms are diffused from the Tb-Fe particles to neighboring Nd-Fe-B melt-spun ribbons, in which Nd atoms in 2:14:1 grains are partially substituted by Tb atoms. The formation of local high-anisotropy (Nd, Tb)(2)Fe14B regions promotes the locally magnetically hardening, suppressing the nucleation of reversed magnetic domains at the low-anisotropy surface magnetic defects. This can be employed to explain the coercivity enhancement of diffusion-processed hot-deformed magnets. In addition, the thermal stability of the magnet is improved due to the higher Curie temperature of (Nd, Tb)(2)Fe14B grain. (C) 2018 Elsevier B.V. All rights reserved.