Nanocrystalline NdFeB magnets fabricated by a modified hot-working process

Nanocrystalline and textured NdFeB magnets were prepared from isotropic melt-spun Nd12Dy2Fe73.2Co6.6Ga0.6B5.6 powder by a modified hot-working process using direct joule heating. The isotropic magnet obtained by current applied (CA) press was composed of randomly oriented Nd2Fe14B grains of 50-100 nm in diameter, and the optimized magnetic properties were B-r=0.81 T (8.1 kG), H-i(c)=2022 kA/m (25.4 kOe), and (BH)(max)=117 kJ/m(3) (14.7 MG Oe). After CA deformation, the grains grew to platelets with 50-100 nm in thickness and 200-400 nm in length, and the magnet showed excellent properties of B-r=1.31 T (13.1 kG), H-i(c)=1457 kA/m (18.3 kOe), and (BH)(max)=333 kJ/m(3) (41.8 MG Oe). (C) 2003 American Institute of Physics.