Magnetic properties of new Nd-Fe-B nanocrystalline with /spl alpha/-Fe as main phase

The /spl alpha/-Fe based Nd-Fe-B magnet with low Nd content has been investigated to develop a new type of rare earth magnet. The amorphous Nd/sub 4/Fe/sub 85.5/B/sub 10.5/ alloy prepared by a rapid quenching technique was crystallized to form only two phases: /spl alpha/-Fe as the main phase, and Nd/sub 2/Fe/sub 14/B as the secondary phase, The coercivity and remanence of the studied alloy were 95.5 kA/m and 1.2 T, respectively. The additions of Mo and Cu to Nd/sub 4/Fe/sub 85.5/B/sub 10.5/ alloy reduced the mean grain size and increased the coercivity up to 207 kA/m. Furthermore, the substitution of 8 at% Co for Fe in Nd/sub 4/Fe/sub 82/B/sub 10/Mo/sub 3/Cu/sub 1/ improved the coercivity, remanence, and Curie point. The coercivity, remanence, and energy product of the Nd/sub 4/Fe/sub 74/Co/sub 8/B/sub 10/Mo/sub 3/Cu/sub 1/ alloy were 219 kA/m, 1.4 T, and 103.5 kJ/m/sup 3/, respectively.