THE MICROSTRUCTURE OF HOT FORMED NEODYMIUM-IRON-BORON MAGNETS WITH ENERGY PRODUCT 48-MG OE

Melt-spun Nd-Fe-B ribbons containing small amounts of Co, Ga, and C we re die upset to 60% and 70% reduction in height in an argon atmosphere between 750 and 800-degrees-C. The magnet, which was die upset 70%, h as a remanence of 14.2 kG, H(ci) of 14.8 kOe, and (BH)max of 48 MG Oe. The interior of the magnet consists of well-aligned Nd2Fe14B grains s eparated by a Nd-rich intergranular phase. Intermixed with such aligne d grains, we observed zones of unaligned fine-grained material without any intergranular phase. Since the intergranular phase is a key facto r for deformation and alignment and it is uniformly distributed in the hot pressed precursor, it will be possible to enhance the alignment f urther by controlling the redistribution of the intergranular phase du ring die upsetting.