Patent ID: 7163591

Claim:
A method of preparing a micro-structured powder for bonded magnets having high coercivity, comprising: (a) mechanically crushing or hydrogen decrepitating a R—Fe—B type anisotropic sintered magnet or scraps thereof, to prepare R—Fe—B type anisotropic permanent magnet powders having an average size of 50–500 μm; (b) mixing the R—Fe—B type anisotropic permanent magnet powders with 1–10 wt % of rare earth fluoride (RF 3 ) powders having a size of 0.1–50 μm, to obtain mixed powders; and (c) thermally treating the mixed powders at 500–1100° C. in a vacuum or an inert gas atmosphere, to prepare R—Fe—B type anisotropic permanent magnet powders.