Abstract: The present invention relates to an R-T-B sintered magnet and a preparation method thereof. The sintered magnet includes a grain boundary region T1, a shell layer region T2 and an R2Fe14B grain region T3; at 10 ?m to 60 ?m from a surface of the sintered magnet toward a center thereof, an area ratio of the shell layer region T2 to the R2Fe14B grain region T3 is 0.1 to 0.3, and a thickness of the shell layer region T2 is 0.5 ?m to 1.2 ?m; and an average coating percent of the shell layer region T2 on the R2Fe14B grain region T3 is 80% or more. In the present invention, by optimizing a preparation process and a microstructure of a traditional rare earth permanent magnet, diffusion efficiency of heavy rare earth in the magnet is improved, such that coercivity of the magnet is greatly improved, and manufacturing cost is reduced.

Abstract: The present invention relates to a modified sintered Nd—Fe—B magnet, and a preparation method and a use thereof. The modified sintered Nd—Fe—B magnet is prepared by performing grain boundary diffusion on a matrix, wherein the matrix is a sintered Nd—Fe—B magnet; a grain boundary diffusion source for the grain boundary diffusion consists of a first diffusion source and a second diffusion source; the first diffusion source is a PrMx alloy, M being at least one selected from a group consisted of Cu, Al, Zn, Mg, Ga, Sn, Ag, Pb, Bi, Ni, Nb, Mn, Co, Fe, Ti, Cr, Zr, Mo and Ge; and the second diffusion source is heavy rare earth Dy and/or Tb.

Abstract: The present invention relates to an R-T-B sintered magnet and a preparation method thereof. The sintered magnet includes a grain boundary region T1, a shell layer region T2 and an R2Fe14B grain region T3; at 10 ?m to 60 ?m from a surface of the sintered magnet toward a center thereof, an area ratio of the shell layer region T2 to the R2Fe14B grain region T3 is 0.1 to 0.3, and a thickness of the shell layer region T2 is 0.5 ?m to 1.2 ?m; and an average coating percent of the shell layer region T2 on the R2Fe14B grain region T3 is 80% or more. In the present invention, by optimizing a preparation process and a microstructure of a traditional rare earth permanent magnet, diffusion efficiency of heavy rare earth in the magnet is improved, such that coercivity of the magnet is greatly improved, and manufacturing cost is reduced.