稀土金属类永久磁铁材料之制造方法

A method for preparing a rare earth permanent magnet material is characterized by comprising the steps of disposing a powder mixture on a surface of a sintered magnet body of R 1 -Fe-B composition wherein R 1 is at least one element selected from rare earth elements inclusive of Sc and Y, the powder mixture comprising a powder containing at least 0.5% by weight of M which is at least one element selected from Al, Cu, and Zn and having an average particle size equal to or less than 300 µm and a powder containing at least 30% by weight of a fluoride of R 2 which is at least one element selected from rare earth elements inclusive of Sc and Y and having an average particle size equal to or less than 100 µm, and heat treating the magnet body having the powder disposed on its surface at a temperature equal to or below the sintering temperature of the magnet body in vacuum or in an inert gas, for causing at least one of M and R 2 in the powder mixture to be absorbed in the magnet body. The invention provides an R-Fe-B sintered magnet with high performance and a minimized amount of Tb or Dy used.