Packing bimodal magnetic particles to fabricate highly dense anisotropic rare earth bonded permanent magnets.

Highly dense and magnetically anisotropic rare earth bonded magnets have been fabricated packing bimodal magnetic particles using a batch extrusion process followed by compression molding technology. The bimodal feedstock was a 96 wt% magnet powder mixture, with 40% being anisotropic Sm-Fe-N (3 μm) and 60% being anisotropic Nd-Fe-B (100 μm) as fine and coarse particles, respectively; these were blended with a 4 wt% polyphenylene sulfide (PPS) polymer binder to fabricate the bonded magnets. The hybrid bonded magnet with an 81 vol% magnet loading yielded a density of 6.