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

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PROBLEM TO BE SOLVED : To provide an alloy for an R-T-B-based rare earth sintered magnet capable of obtaining an R-T-B-based magnet having high coercive force without increasing the content of Dy contained in an R-T-B-based alloy. SOLUTION : There is provided an alloy for an R-T-B-based rare earth sintered magnet which comprises : R; T essentially containing Fe; a metal element M containing one or more metals selected from Al, Ga and Cu; B; and inevitable impurities and contains 13 to 15 atomic% of R, 5.0 to 6.0 atomic% of B and 0.1 to 2.4 atomic% of M. T is the remainder, the ratio of Dy in all the rare earth elements is 0 to 65 atomic%, and the alloy satisfies the following (expression 1) and comprises a main phase mainly containing R2Fe14B and alloy grain boundary phases containing R in an amount larger than the main phase, and a distance between alloy grain boundary phases is 1.0 μm or more and 3 μm or less. 0.0049Dy+0.34≤B/TRE≤0.0049Dy+0.36 (Expression 1), wherein Dy represents atomic%, B represents atomic% and TRE represents a concentration (atomic%) of the total rare-earth elements. COPYRIGHT : (C)2014, JPO&INPIT