Patent ID: 7972448

Claim:
A method for producing an anisotropic magnetic powder, comprising: providing a starting material comprising an SE-TM-B alloy, wherein SE is a rare earth element and TM is a transition metal, said starting material comprising a magnetic material with an anisotropic orientation and an average grain size of less than 0.1 mm, said starting material further comprising a hard magnetic content greater than 90% by volume, foreign phases smaller than 0.5 mm in size, and a crystal size and article size such that the crystal size is at most 75% of the particle size; producing a mixture comprising a TM X B phase in said starting material by a hydrogenation/dehydrogenation treatment without homogenization treatment at high temperate comprising: a first hydrogenation comprising heating said starting material comprising said SE-TM-B alloy under a hydrogen pressure sufficient to produce a hydride of the SE-TM-B alloy, and then a second hydrogenation comprising exposing the hydride resulting from said first hydrogenation to a hydrogen pressure and an elevated temperature sufficient to induce a phase transition to produce said TM X B phase, and afterward dehydrogenating and producing a reverse phase transition to produce an anisotropic magnetic powder having a crystallographic orientation that matches a crystallographic orientation of said TM X B phase and that has a fine and uniformly granular microstructure.