RARE EARTH PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To provide a high performance R-Fe-B based permanent magnet (R is two kinds or more selected from rare earth elements including Sc and Y) using a small quantity of Tb or Dy. SOLUTION : In a sintered magnet body having composition of R1aR2bTcAdFeOfMg, constitutional elements F and R2 are distributed such that the concentration of component increases in average from the center of the magnet body toward the surface thereof. At the grain boundary portion surrounding the main phase crystal grain consisting of tetragonal (R1, R2)2T14A in the sintered magnet body, concentration of R2/(R1+R2) contained in the grain boundary is higher than that in the main phase crystal grain in average, and an acid fluoride of (R1, R2) exists in the grain boundary down to a region of at least 20 μm from the surface of the magnet body in the grain boundary. COPYRIGHT : (C)2007, JPO&INPIT