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 comprises R2T14B crystal as primary-phase grains 11, 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 partially include low-RH crystal phases 21 therein. The low-RH crystal phases 21 are formed by R2T14B crystal, of which the RH concentration is relatively low in comparison to a RH concentration in the whole primary-phase grains. When the abundance rate of primary-phase grains including low-RH crystal phases 21 in a magnet surface layer portion is denoted by rs(%), and the abundance rate of primary-phase grains including low-RH crystal phases 21 in a magnet center portion is denoted by rc(%), rs-rc≥20%. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2019, JPO&INPIT