SINTERED NEODYMIUM MAGNET

摘要

Provided is a NdFeB system sintered magnet which is produced by the grain boundary diffusion method and yet has a high coercive force and squareness ratio with only a small decrease in the maximum energy product. A NdFeB system sintered magnet according to the present invention is a NdFeB system sintered magnet having a base material produced by orienting powder of a NdFeB system alloy and sintering the powder, with Dy and/or Tb (the "Dy and/or Tb" is hereinafter called R H ) attached to and diffused from a surface of the base material through the grain boundary inside the base material by a grain boundary diffusion treatment, wherein the number of grain-boundary triple points at which the difference C t -C w between the R H content C t (wt%) at the grain-boundary triple point and the R H content C w (wt%) at a two-grain boundary portion leading to that grain-boundary triple point is equal to or smaller than 4 wt% is equal to or larger than 60 % of the total number of grain-boundary triple points.