Rare earth permanent magnet and its manufacturing method

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PROBLEM TO BE SOLVED : To provide a high performance R-Fe-B sintered magnet and a manufacturing method therefor that assure superior productivity and having an increased coersive force, while controlling reduction of residual magnetic flux density with less amount of Tb or Dy or without Tb or Dy by utilizing an alloy powder mainly formed of an intermetallic compound as a material to be coated or diffused on the sintered material. SOLUTION : In the manufacturing process of the rare earth permanent magnet, the sintered material and powder are subjected to heat treatment within the vacuum or inert gas atmosphere at a temperature lower than the sintering temperature of the sintered material under the condition where powder of alloy, formed of M1d-M2e (M1and M2are one kind or two or more kinds of materials selected from among Al, Si, C, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, Hf, Ta, W, Pb, and Bi, but M1is different from M2; 0.1≤e≤99.9; and d is a remainder) and containing an intermetallic compound phase in the 70 volume% or higher is provided on the front surface of a sintered material, having the composition of Ra-T1b-Bc (R is a rare earth element containing Y and Sc; T1is Fe and/or Co; a, b, and c represent atom percent; 12≤a≤20; 4.0≤c≤7.0; b is remainder). Accordingly, the high performance R-Fe-B sintered magnet ensuring superior productivity and having increased coersive force, while controlling reduction of residual magnetic flux density can be obtained. COPYRIGHT : (C)2009, JPO&INPIT