A step of, while a powder of an RLM alloy (where RL is Nd and/or Pr; M is one or more elements selected from among Cu, Fe, Ga, Co, Ni and Al) and a powder of an RH compound (where RH is Dy and/or Tb; and the RH compound is one, or two or more, selected from among an RH fluoride, an RH oxide, and an RH oxyfluoride) are present on the surface of a sintered R-T-B based magnet, performing a heat treatment at a sintering temperature of the sintered R-T-B based magnet or lower is included. The RLM alloy contains RL in an amount of 65 at % or more, and the melting point of the RLM alloy is equal to or less than the temperature of the heat treatment. The heat treatment is performed while the RLM alloy powder and the RH compound powder are present on the surface of the sintered R-T-B based magnet at a mass ratio of RLM alloy:RH compound=9.6:0.4 to 5:5.

A method for producing a nanocrystalline rare earth magnet having a grain and a grain boundary phase includes: quenching a melt of a rare earth magnet composition to form a quenched thin ribbon having a nanocrystalline structure; sintering the quenched thin ribbon to obtain a sintered body; heat treating the sintered body at a temperature which is higher than a lowest temperature in a first temperature range where the grain boundary phase diffuses or flows, and which is lower than a lowest temperature in a second temperature range where the grain becomes coarse; and quenching the heat treated sintered body to 200° C. or less at a cooling speed of 50° C./min or more.

A method for manufacturing a multicomponent permanent magnet, and a multicomponent permanent magnet are proposed. The multicomponent permanent magnet has a first permanent magnet having a R-T-B-composition, wherein R is at least one selected from the group consisting of Y, Ce, La, Pr, Nd, Sm, Eu and Gd and T is one or more transition metal elements including Fe; and a second permanent magnet having a R-T-B-composition, wherein R is at least one selected from the group consisting of Y, Ce, La, Pr, Nd, Sm, Eu and Gd and T is one or more transition metal elements including Fe, the second magnet including at least one of a heavy rare earth element (HRE) and an increased amount of Ce and/or Co, the second magnet having different magnetic properties, in particular a higher coercivity, than the first magnet. The first magnet and the second magnet are connected mechanically, wherein the connection is electrically conductive with an adjusted electrical resistivity.

The present disclosure provides a method for preparing a high-coercivity sintered NdFeB magnet. The method including the steps of: S1, Providing a NdFeB powder as a main material; S2, Vacuum coating a layer of a rare earth alloy R.sub.xH.sub.(100-x) on a surface of a metal nano-powder M to obtain an auxiliary alloy material with a core-shell structure, with R being selected from one or more of Dy, Tb, Pr, Nd, La, and Ce; H being selected from one or more of Cu, Al, and Ga; the nano-powder M being selected from one or more of Mo, W, Zr, Ti, and Nb; 0≤x≤90 wt. %; S3, Adding the auxiliary alloy material obtained by step S2 to the NdFeB powder of step S1 and mixing, then orientation pressing of the mixture to obtain a compact body; and S4, Sintering and annealing treatment of the compact body to obtain the high-coercivity sintered NdFeB magnet.

A method for manufacturing a sintered magnet according to one embodiment of the present disclosure is provided. The method includes producing an R-T-B-based magnetic powder through a reduction-diffusion method, and sintering the R-T-B-based magnetic powder, wherein R is a rare earth element, and T is a transition metal, and wherein the producing the magnetic powder includes adding a refractory metal sulfide powder to a R-T-B-based raw material.

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. A wider and longer diffusion channel formed by a low-melting-point alloy containing Pr preferentially entering the inside of the magnet is used as a channel for rapid diffusion of a heavy rare earth element

To provide an R-T-B based permanent magnet having a high residual magnetic flux density Br at room temperature and a high coercivity HcJ at high temperature. In the R-T-B based permanent magnet, R is a rare earth element, T is an iron group element, and B is boron, and the R-T-B based permanent magnet includes a light rare earth element and a heavy rare earth element as R. The R-T-B based permanent magnet further includes Al, Ga, and Zr. With respect to 100 mass % of the R-T-B based permanent magnet, a total content of R is 28.50 mass % to 30.25 mass % (not including 28.50 mass %), B content is 0.93 mass % to 0.98 mass %, Al content is 0.03 mass % to 0.19 mass %, Ga content is 0.03 mass % to 0.15 mass %, and Zr content is 0.30 mass % to 0.50 mass %.

To provide an R—Fe—B-based rare earth magnet excellent in the squareness and magnetic properties at high temperatures, and a production method thereof.

The present disclosure provides a rare earth magnet including a main phase 10 and a grain boundary phase 20 present. The overall composition of the rare earth magnet of the present disclosure is represented, in terms of molar ratio, by the formula: (R.sup.1.sub.(1-x)La.sub.x).sub.y(Fe.sub.(1-z)Co.sub.z).sub.(100-y-w-v)B.sub.wM.sup.1.sub.v, wherein R.sup.1 is one or more predetermined rare earth elements, and M.sup.1 is one or more predetermined elements, and wherein 0.02≤x≤0.1, 12.0≤y≤20.0, 0.1≤z≤0.3, 5.0≤w≤20.0, and 0≤v≤2.0. The main phase 10 has an R.sub.2Fe.sub.14B-type crystal structure, the average particle diameter of the main phase 10 is from 1 to 10 μm, and the volume ratio of a phase having an RFe.sub.2-type crystal structure in the grain boundary phase 20 is 0.60 or less relative to the grain boundary phase 20.

Provided is a rare earth magnet that allows suppressing deterioration of magnetic properties and a method for manufacturing the same. The rare earth magnet of the present disclosure includes a magnet body containing a rare earth element R1, a transition metal element T, and boron B and includes a main phase. A region in the vicinity of a corner portion of the magnet body of a constituent surface constituting a surface of the magnet body is a processed surface on which a removal process has been performed, and a region closer to a center than the region in the vicinity of the corner portion of the constituent surface is a non-processed surface on which the removal process is not performed.

An R-T-B based permanent magnet includes a rare earth element R, a transition metal element T, and B. The permanent magnet includes at least Nd as R. The permanent magnet includes at least Fe as T. The permanent magnet contains main phase grains and R-rich phases. The main phase grains include at least R, T, and B. The R-rich phases include at least R. The main phase grains observed in a cross section of the permanent magnet are flat. The cross section is parallel to an easy magnetization axis direction of the permanent magnet. Each of the R-rich phases is located between the main phase grains. An average value of intervals between the R-rich phases in the easy magnetization axis direction is from 5 μm to a width of the permanent magnet in the easy magnetization axis direction.