R-T-B BASED SINTERED MAGNET

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PROBLEM TO BE SOLVED : To provide an R-T-B based sintered magnet which is low cost and enables the increase in residual magnetic flux density and coercive force. SOLUTION : An R-T-B based sintered magnet 1 comprises R2T14B crystal as primary-phase grains, where R represents one or more kinds of rare earth elements, including a heavy rare earth element RH as an essential element, T represents one or more kinds of transition metal elements, including Fe or Fe and Co as an essential element, and B represents boron. The primary-phase grains are partially composed of inverted core shell primary-phase grains 11. The inverted core shell primary-phase grains 11 each have a core part 11a and a shell part 11b. When a total RH concentration (at%) in the core part 11a is denoted by CRC, and a total RH concentration (at%) in the shell part 11b is denoted by CRS, CRC/CRS>1.0. The abundance rate of the inverted core shell primary-phase grains 11 at the grain boundaries 12 in a magnet surface layer portion is larger than that in a magnet center portion. SELECTED DRAWING : Figure 2 COPYRIGHT : (C)2019, JPO&INPIT