Dy6Fe13Cu grain boundary restructured Nd-Fe-B permanent magnets

Pursuing high coercivity has long been a focus of the whole Nd-Fe-B community to enable its widespread application in emerging sectors. In the present work, the controlling mechanism of high-coercivity Dy6Fe13Cu grain boundary restructured (GBR) magnets is investigated. Compared to the starting magnet with a coercivity value of 17.2 kOe, the coercivity of the restructured magnet with 3 wt% Dy6Fe13Cu (equals to 1.65 wt% Dy) increases to 22.8 kOe, with the coercivity increment level of 3.39 kOe per unit weight percentage of Dy addition. Results show that low-melting-point Dy6Fe13Cu additive contributes to the formation of continuous intergranular layer isolating ferromagnetic 2:14:1 grains and promotes the infiltration of Dy into the (Nd, Dy)2Fe14B magnetically hardening shell. Both effects enable the more efficient utilization of scarce Dy to enhance the coercivity of bulk Nd-Fe-B magnets. It delights future work for fabricating high-coercivity magnets via the GBR approach.