METHOD OF PRODUCING R-T-B SINTERED MAGNET

An application step of applying an adhesive agent to an application area of a surface of a sintered R-T-B based magnet, an adhesion step of allowing a particle size-adjusted powder that is composed of a powder of an alloy or a compound of a heavy rare-earth element RH which is at least one of Dy and Tb to adhere to the application area of the surface of the sintered R-T-B based magnet, and a diffusing step of heating it at a temperature which is equal to or lower than a sintering temperature of the sintered R-T-B based magnet to allow the heavy rare-earth element RH contained in the particle size-adjusted powder to diffuse from the surface into the interior of the sintered R-T-B based magnet are included. The particle size of the particle size-adjusted powder is set so that, when powder particles composing the particle size-adjusted powder are placed on the entire surface of the sintered R-T-B based magnet to form a single particle layer, the amount of heavy rare-earth element RH contained in the particle size-adjusted powder is in a range from 0.6 to 1.5% with respect to the sintered R-T-B based magnet by mass ratio.