Patent ID: 8377233

Claim:
A method for preparing a rare earth permanent magnet material comprising the steps of: disposing a powder comprising one or more members selected from the group consisting of an oxide of R 2 , a fluoride of R 3 , and an oxyfluoride of R 4 wherein R 2 , R 3 and R 4 each are one or more elements selected from the group consisting of rare earth elements inclusive of Y and Sc on a sintered magnet form to be heat treated of a R 1 —Fe—B composition, wherein R 1 is one or more elements selected from among rare earth elements inclusive of Y and Sc, the sintered magnet form having a dimension of at least 0.5 mm in a magnetic anisotropy direction and at least 4 mm along its maximum side, and then heat treating the magnet form and the powder at a temperature equal to or below the sintering temperature of the magnet in vacuum or in an inert gas, and then grinding, or plating or painting the magnet form as a final treatment after the heat treatment.