RARE EARTH-IRON-BORON BASED SINTERED MAGNET AND METHOD FOR MANUFACTURING THE SAME

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SOLUTION : An R-Fe-B based sintered magnet has a composition including R, M1 (M1 represents two or more kinds of elements selected from Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb and Bi), M2 (M2 represents at least one element selected from Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W), B and Fe. The R-Fe-B based sintered magnet comprises : a main phase including an R2 (Fe, (Co))14B intermetallic compound; and a grain boundary phase including an R-Fe(Co)-M1 phase including "A" phase which is present in such a crystal form that a crystallite of 10 nm or more in grain diameter is formed at each triple point of grain boundaries, and "B" phase which is different from the "A" phase in composition and which is present at a grain boundary between two particles, or at a grain boundary between two particles and a triple point of grain boundaries in an amorphous form and/or such a microcrystal form that a crystallite of less than 10 nm in grain diameter is formed. EFFECT : The R-Fe-B based sintered magnet of the invention has a high coercive force even at a high temperature, and it exhibits a high performance as a rare earth permanent magnet used in a device used under a high-temperature condition. SELECTED DRAWING : Figure 3 COPYRIGHT : (C)2018, JPO&INPIT