Patent ID: 8801870

Claim:
A method for making a NdFeB sintered magnet including processes of coating a NdFeB sintered magnet base material compact with a powder containing R h , where R h represents Dy and/or Tb, then heating the NdFeB sintered magnet base material compact, and thereby diffusing R h in the powder into the NdFeB sintered magnet through a grain boundary, and obtaining a NdFeB sintered magnet that has a coercive force H c1 , value within a range of from 19.0 to 26.9 kOe, wherein: the powder contains 0.5 through 50 weight percent of Al in a metallic state; at least a part of the Al is diffused by the heating through the grain boundary; and an amount of oxygen contained in the NdFeB sintered magnet base material compact is equal to or less than 0.4 weight percent.