METHOD FOR MANUFACTURING R-T-B BASED SINTERED MAGNET

PROBLEM TO BE SOLVED : To apply a layer of powder particles including a heavy rare earth element RH to a surface of an R-T-B based sintered magnet efficiently and uniformly without waste in order to increase HcJ by diffusing a heavy rare earth element RH into the R-T-B based sintered magnet. SOLUTION : A method for manufacturing an R-T-B based sintered magnet comprises : a step of preparing granulated powder into which powder of an alloy or compound of a heavy rare earth element RH is granulated together with a binder, provided that the element RH is at least one of Dy and Tb (where RH is one or more kinds selected from Dy and Tb, and the RH compound is one or more kinds selected from RH fluoride, RH acid fluoride and RH oxide); a deposition step of heating at least a surface of an R-T-B based sintered magnet (where R is a rare earth element, and T is Fe, or Fe and Co) to deposit the granulated powder on the sintered magnet surface; and a diffusion step of performing a thermal treatment on the sintered magnet with the granulated powder deposited thereon at a temperature equal to or lower than a sintering temperature to diffuse the heavy rare earth element RH included in the granulated powder into the sintered magnet from the surface thereof. SELECTED DRAWING : Figure 1A COPYRIGHT : (C)2018, JPO&INPIT