Coercivity enhancement for Nd-La-Ce-Fe-B sintered magnets by tailoring La and Ce distributions

Inferior intrinsic magnetic properties of (La/Ce)(2)Fe14B to Nd2Fe14B compound pose a big challenge for the Nd-La-Ce-Fe-B sintered magnets to provide an equivalent performance to the commercial Nd-Fe-B ones. To suppress the magnetic dilution, La/Ce distributions within 2: 14: 1 phase are intentionally tailored in the present work. At the same La-Ce substitution level of 12 wt%, the coercivity has been substantially increased to 1.36 T by constructing the coexisting Nd-rich shell @ La/Ce-rich core and La/Ce-rich shell @ Nd-rich core morphologies, compared to the La/Ce homogenously distributed magnet (0.76 T) and the one with singular Nd-rich core surrounded by La/Ce-rich shell (0.82 T). This is attributed to combined effects of magnetically hardening Nd-rich shell in suppressing the reversal domain nucleation, and continuous grain boundary layer in reducing the short-range exchange coupling between adjacent ferromagnetic grains. It may act as part of endeavors to promote the Nd-La-Ce-Fe-B sintered magnets for commercial application. (C) 2018 Elsevier B.V. All rights reserved.