R-Fe-B TYPE SINTERED MAGNET AND METHOD FOR MAKING THE SAME

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The present invention relates to an R-Fe-B type sintered magnet comprising : M_2 boride phase at grain-boundary triple junctions, without R_1.1Fe_4B_4 compound phase, with a main phase of (R, HR)_2(Fe, (Co))_14B (R is a rare earth elements, HR is Dy, Tb, or Ho), coated with an HR rich layer having a thickness of 0.01-1.0 m; having a core/shell structure coated by a grain-boundary phase containing (R, HR)-Fe(Co)-M_1 phase of an amorphous and/or fine crystalline of 10 nm or less or containing the above (R, HR)-Fe(Co)-M_1 phase and a crystalline of R having 50 at% or more, or (R, HR)-M_1 phase of amorphous and fine crystalline of 10 nm or less with a surface coating rate of 50% or more for a main phase with the HR rich layer of (R, HR)-Fe(Co)-M_1 phase; and a width of the grain-boundary phase in the main phase 2 particles being 10 nm or more and 50 nm or more in average. The magnet of the present invention provides coercivity having at least 10 kOe or more in a content of Dy, Tb, and Ho.