R-Fe-B SINTERED MAGNET AND MAKING METHOD

An R—Fe—B base sintered magnet of a composition consisting essentially of 12 to 17 at % of R which is at least two of yttrium and rare earth elements and essentially contains Nd and Pr, 0.1 to 3 at % of M1 which is at least two elements selected from the group consisting of Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi, 0.05 to 0.5 at % of M2 which is at least one element selected from the group consisting of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W, 4.5+2×m to 5.9+2×m at % of boron wherein m is at % of M2, up to 10 at % of Co, up to 0.5 at % of carbon, up to 1.5 at % of oxygen, up to 0.5 at % of nitrogen, and the balance of Fe, and containing an intermetallic compound R2(Fe,(Co))14B as a main phase, wherein

• the magnet contains an R—Fe(Co)-M1 phase consisting essentially of 25 to 35 at % of R, 2 to 8 at % of M1, up to 8 at % of Co, and the balance of Fe as a grain boundary phase, the R—Fe(Co)-M1 phase contains an A phase which is crystalline with crystallites having a grain size of at least 10 nm formed at grain boundary triple junctions, and a B phase which is amorphous and/or nanocrystalline with crystallites having a grain size of less than 10 mm formed at intergranular grain boundaries or intergranular grain boundaries and grain boundary triple junctions, the B phase having a different composition from the A phase.