Coercivity enhancement in Nd-Fe-B sintered permanent magnet by Dy nanoparticles doping

Nd-Fe-B permanent magnets with a small amount of Dysprosium (Dy) nanoparticles doping were prepared by conventional sintered method, and the microstructure and magnetic properties of the magnets were studied. Investigation shows that the coercivity rises gradually, while the remanence decreases simultaneously with increased Dy doping amount. As a result, the magnet with 1.5 wt.% Dy exhibits optimal magnetic properties. Further investigation presumed that Dy is enriched as (Nd, Dy)(2)Fe14B phase in the surface region of the Nd2Fe14B matrix grains indicated by the enhancement of the magneto-crystalline anisotropy field of the Nd2Fe14B phase. As a result, the magnet doped with a small amount of Dy nanoparticles possesses remarkably enhanced coercivity without sacrificing its magnetization noticeably. (C) 2010 Elsevier B.V. All rights reserved.