R-T-B BASED SINTERED MAGNET AND METHOD FOR MANUFACTURING THE SAME

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PROBLEM TO BE SOLVED : To provide : an R-T-B based sintered magnet which enables the effective increase in high coercive force by use of a rare earth element capable of achieving a high coercive force; and a method for manufacturing the R-T-B based sintered magnet. SOLUTION : An R-T-B based sintered magnet comprises : first main phases 1 consisting of crystal grains of an R-T-B based alloy including a light rare earth element as R; second main phases 2 consisting of crystal grains of an R-T-B based alloy including a heavy rare earth element as R; surface phases 5 surrounding surfaces of crystal grains constituting the two main phases 1, 2; and grain boundary alloy phases 3 present at triple points of grain boundaries. In the concentration of the heavy rare earth element, the first main phases 1 and the grain boundary alloy phases 3 are lower than the second main phases 2 and the surface phases 5. A method for manufacturing an R-T-B based sintered magnet comprises : mixing a first raw material 11 consisting of an R-T-B based alloy including a light rare earth element as R, and a second raw material 12 consisting of an R-T-B based alloy including, as R, a heavy rare earth element at a concentration higher than that in the first raw material 11; and sintering the resultant mixture. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2019, JPO&INPIT