Effects of preparation processes on structure and magnetic properties of Nd2Fe14B/α-Fe-type nanocomposite magnets

The structure and magnetic properties of Nd8.4Fe86Mo1.1B4.5 nanostructured magnets prepared by mechanical alloying (MA), compared with those by mechanical milling (MM), were studied. The intrinsic coercivity mu H-0(c), the reduced remanence J(r)/J(s), and the maximum magnetic energy product (BH)(max) for Nd8.4Fe86Mo1.1B4.5 magnets were prepared by MM were notably higher than the values of the corresponding MA-prepared samples. The average grain sizes of both alpha -Fe and Nd2Fe14B in the MM-prepared samples were measurably smaller than corresponding values of the MA-prepared samples. A more homogeneous distribution of alpha -Fe grains in the MM-prepared samples than in the MA-prepared samples was obtained.