R-Fe-B RARE EARTH SINTERED MAGNET

摘要

An R-Fe-B based rare-earth sintered magnet according to the present invention includes, as a main phase, crystal grains of an R 2 Fe 14 B type compound that includes Nd, which is a light rare-earth element, as a major rare-earth element R. The magnet includes a heavy rare-earth element RH (which is at least one of Dy and Tb) that has been introduced through the surface of the sintered magnet by diffusion. The magnet has a region in which the concentration of the heavy rare-earth element RH in a grain boundary R-rich phase is lower than at the surface of the crystal grains of the R 2 Fe 14 B type compound but higher than at the core of the crystal grains of the R 2 Fe 14 B type compound.