METHOD FOR PRODUCING RARE EARTH PERMANENT MAGNET MATERIAL

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Disclosed is a method for producing a rare earth permanent magnet material which is characterized in that a sintered magnet body and a mixed powder are subjected to a heat treatment in vacuum or in an inert gas at a temperature not higher than the sintering temperature of the sintered body, while having the mixed powder present on the surface of the sintered magnet body, so that at least one of M and R2 contained in the mixed powder is absorbed into the magnet body. The sintered magnet body has an R1-Fe-B composition (wherein R1 represents one or more elements selected from rare earth elements including Sc and Y), and the mixed powder is composed of a powder containing not less than 0.5% by mass of M (M represents one or more elements selected from Al, Cu and Zn) and having an average particle diameter of not more than 300 μm, and another powder containing not less than 30% by mass of a fluoride of R2 (R2 represents one or more elements selected from rare earth elements including Sc and Y) and having an average particle diameter of not more than 100 μm. This method enables to obtain a high-performance R-Fe-B sintered magnet wherein only a few Tb or Dy is used.