Method for preparing rare earth permanent magnet material

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A permanent magnet material is prepared by covering an anisotropic sintered magnet body of formula : R 1 x (Fe 1-y Co y ) 100-x-z-a B z M a wherein R 1 is a rare earth element, M is A1, Cu or the like, with a powder comprising an oxide of R 2 , a fluoride of R 3 or an oxyfluoride of R 4 wherein R 2 , R 3 , and R 4 are rare earth elements, and having an average particle size up to 100 µm, heat treating the powder-covered magnet body in a hydrogen gas-containing atmosphere for inducing disproportionation reaction on R 1 2 Fe 14 B compound, and continuing heat treatment at a reduced hydrogen gas partial pressure for inducing recombination reaction to said compound, thereby finely dividing said compound phase to a crystal grain size up to 1 µm, and for effecting absorption treatment, thereby causing R 2 , R 3 or R 4 to be absorbed in the magnet body.