RECENT DEVELOPMENTS OF HIGH-PERFORMANCE NEOMAX MAGNETS

For further improvement in achieving extremely high magnetic properties of Nd-Fe-B sintered magnets, extensive investigation has been done to densify the magnet up to the theoretical value, to increase the volume fraction of the Nd2Fe14B matrix phase, and to achieve a high degree of alignment. By controlling chemical composition and the amount of constituent phases, improving particle size distribution, and adopting the isostatic pressing method to get better alignment of fine particles, we have succeeded in obtaining a high-performance magnet having residual flux density (B-r) of 1.495 T (14.95 kG), maximum energy product [(BH)(max)] of 431 kJ/m(3) (54.2 MGOe), and intrinsic coercivity (iH(c)) of 845 kA/m (10.62 kOe).