Patent ID: 7244318

Claim:
A method of producing a sintered permanent magnet comprising the steps of: preparing a blended powder including a first powder and a second powder, the first powder containing an R 2 T 14 Q phase (R is at least one element selected from the group consisting of all rare-earth elements and Y (yttrium) excluding Dy and Tb, T is at least one element selected from the group consisting of all transition elements, and Q is at least one element selected from the group consisting of B (boron) and C (carbon)) as a main phase, the second powder containing an R1 2 T 17 phase (R1 is at least one element selected from the group consisting of Dy and Tb) at 25wt % or more of the second powder; compacting the blended powder; and sintering the compacted powder to concentrate Dy and/or Tb in a surface portion of the R 2 T 14 Q phase, wherein the first powder is a powder of alloy represented by a composition formula of R x T 100−x−y Q y , and x and y for defining molar fractions satisfy the following relationships, respectively: 12.5≦x≦18(at %); and 5.5≦y≦20 (at %), and the second powder is a powder of alloy represented by a composition formula of R1 p Cu r T 100−p−r , and p and r for defining molar fractions satisfy the following relationships respectively: 10≦p≦20(at %); and 0.1≦r≦10(at %), and wherein the step of preparing the blended powder includes a step of performing a hydrogen embrittlement process to the alloy for the second powder, thereby obtaining an average particle diameter of the second powder of 100 μm or less.