Effects of preparation processes on structure and magnetic properties of Nd2Fe14B/alpha-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 mechan ical milling (MM), were studied. The intrinsic coercivity mu H-0(c), the re duced 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 th an the values of the corresponding MA-prepared samples. The average grain s izes of both alpha -Fe and Nd2Fe14B in the MM-prepared samples were measura bly smaller than corresponding values of the MA-prepared samples. A more ho mogeneous distribution of alpha -Fe grains in the MM-prepared samples than in the MA-prepared samples was obtained.