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 high in residual magnetic flux density Br and coercive force HcJ, and superior in corrosion resistance and production stability. SOLUTION : In an R-T-B based sintered magnet, R represents a rare earth element; T represents a metal element other than the rare earth element; and B represents boron, or boron and carbon. The R-T-B based sintered magnet comprises : at least Tb as R; and at least Fe, Cu, Mn, Al and Co as T. Supposing that the total mass of the R-T-B based sintered magnet is 100 mass%, the content of R is 28.0-32.0 mass%, the content of Cu is 0.04-0.50 mass%, the content of Mn is 0.02-0.10 mass%, the content of Al is 0.15-0.30 mass%, the content of Co is 0.50-3.0 mass%, and the content of B is 0.85-1.0 mass%. Supposing that the content of Tb in a surface portion is Tb1, and the content of Tb in a center portion is Tb2, Tb2/Tb1 is equal to or greater than 0.40 to less than 1.0. SELECTED DRAWING : Figure 2 COPYRIGHT : (C)2017, JPO&INPIT