R-T-B BASED PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To provide an R-T-B based permanent magnet having a high residual magnetic flux density and a high coercive force. SOLUTION : An R-T-B based permanent magnet comprises : R which is a rare earth element; T which represents Fe and Co; and B which is boron. The R-T-B based permanent magnet includes at least Dy and Tb as R; and M, provided that M is one or more elements selected from a group consisting of Cu, Ga, Al, Mn, Zr, Ti, Cr, Ni, Nb, Ag, Hf, Ta, W, Si, Bi and Sn, and at least Cu is involved as M. Supposing that the total mass of R, T, B and M is 100 mass%, the total content of R is 28.05-30.60 mass%, the content of Dy is 1.0-6.5 mass%, the content of Cu is 0.04-0.50 mass%, the content of Co is 0.5-3.0 mass%, and the content of B is 0.85-0.95 mass%. In the R-T-B based permanent magnet, a concentration distribution of Tb lowers from the outside of the R-T-B based permanent magnet toward the inside. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2019, JPO&INPIT