Patent ID: 8268093

Claim:
A method for producing an R—Fe—B based porous magnet, the method comprising the steps of: providing an R—Fe—B based rare-earth alloy powder with a mean particle size that is less than 10 μm; making a powder compact by compacting the R—Fe—B based rare-earth alloy powder; producing hydrogenation and disproportionation reactions by heat-treating the powder compact at a temperature of 650° C. to less than 900° C. within a hydrogen gas; producing desorption and recombination reactions by heat-treating the powder compact at a temperature of 650° C. to less than about 900° C. within either a vacuum or an inert atmosphere, which forms an R—Fe—B based porous magnet that has a density of 3.5 g/cm 3 to 7.0 g/cm 3 and that has micropores with a major axis of 1 μm to 20 μm; and decreasing a temperature of the R—Fe—B based porous magnet to room temperature, which forms the R—Fe—B based porous magnet that has a density of 3.5 g/cm 3 to 7.0 g/cm 3 at room temperature.