R-Fe-B rare earth sintered magnet

文件类型：PDF文档
文件大小：1157K
An R-Fe-B based rare-earth sintered magnet is provided which comprises, as a main phase, crystal grains of an R2Fe14B type compound that includes a light rare-earth element RL (which is at least one of Nd and Pr) as a major rare-earth element R, wherein the magnet further includes a heavy rare-earth element RH (which is at least one element selected from the group consisting of Dy, Ho and Tb and) which has been introduced from its surface by grain boundary diffusion, and wherein in a surface region of the magnet, which is defined from the surface to a depth of 100 µm, there is a difference of at least 1 at% between the concentration of the heavy rare-earth element RH at a center portion of the crystal grains of the R2Fe14B type compound and that of the heavy rare-earth element RH on a grain boundary phase of the crystal grains of the R2Fe14B type compound.