R-Fe-B SINTERED MAGNET AND MAKING METHOD

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The present invention provides an R-Fe-B-based sintered magnet having high coercivity at a high temperature. The R-Fe-B-based sintered magnet essentially comprises R (at least two rare earth elements and essentially contains Nd and Pr), M_1 including at least two among Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb and Bi, M_2 including at least one among Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, and the remainder consisting of Fe, and contains an intermetallic compound R_2(Fe, (Co))_14B as a main phase. The magnet contains an R-Fe(Co)-M_1 phase as a grain boundary phase. The R-Fe(Co)-M_1 phase contains an A-phase which is a crystalline structure having a crystallite of at least 10 nm formed at a grain boundary triple junction, and a B-phase which is a nano-crystalline structure having a crystallite less than 10 nm formed at a non-crystalline and/or an intercrystalline grain boundary or an intercrystalline grain boundary and a grain boundary triple junction selectively.COPYRIGHT KIPO 2018