R a-T a-B based sintered magnet

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The present invention provides a permanent magnet with both a high corrosion resistance and magnetic properties compared to the existing R-T-B based magnets. It is a R-T-B based sintered magnet (wherein, R includes Y (yttrium) and R1 as essential, R1 is at least one kind of rare earth elements except Y but includes Nd as essential, and T is at least one kind of transition metal element including Fe or the combination of Fe and Co as essential). By allowing the ratio of R1 to Y (R1 : Y) in the R contained in the grain boundary phase to be 80 : 20?35 : 65 in terms of the calculated molar ratio of the grain boundary phase and adding Y to the raw materials of the R-T-B based magnet, Y segregates at the triple point, and corrosion of grain boundary phase is prevented by oxidized Y.