The permanent magnet comprises a main phase structure of R.sub.2T.sub.14B crystal grains, and R is a rare earth element; T comprises at least Mn, Fe, and optionally a transition metal comprising Co; B is boron; the permanent magnet further comprises Mn and heavy rare earth elements which are distributed in a grain boundary in a diffusion mode. The heavy rare earth element is selected from at least one selected from Dy, Ho and Tb. According to the rare earth permanent magnet prepared through the preparation method, more heavy rare earth elements can be diffused into the magnet core along the grain boundary, Hcj distribution of the permanent magnet is improved, and meanwhile the corrosion resistance and the mechanical property of the permanent magnet are improved.

The invention relates to a method for producing a permanent magnet from a magnetic base material, wherein the magnetic base material is shaped, wherein a raw form is created, wherein the raw form is subjected to grain refinement, wherein the raw form is sintered, wherein the permanent magnet is produced.

The present invention provides an R-T-B based permanent magnet capable of improving a coercive force HcJ while maintaining a residual magnetic flux density Br.

The R-T-B based permanent magnet includes Ga. R is one or more selected from rare earth elements, T is Fe or a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet has main phase grains including a crystal grain having an R.sub.2T.sub.14B crystal structure and grain boundaries formed between adjacent two or more main phase grains, and 0.030[Ga]/[R]0.100 is satisfied in which [Ga] represents an atomic concentration of Ga and [R] represents an atomic concentration of R in the main phase grains.

The present invention provides an R-T-B based permanent magnet capable of improving a coercive force HcJ while maintaining a residual magnetic flux density Br.

The R-T-B based permanent magnet includes Ga. R is one or more selected from rare earth elements, T is Fe or a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet has main phase grains including a crystal grain having an R.sub.2T.sub.14B crystal structure and grain boundaries formed between adjacent two or more main phase grains, and 0.030[Ga]/[R]0.100 is satisfied in which [Ga] represents an atomic concentration of Ga and [R] represents an atomic concentration of R in the main phase grains.

A permanent magnet 2 includes Nd, Fe, and B, the permanent magnet 2 contains a plurality of main phase grains; and grain boundaries positioned between the main phase grains, the main phase grains include Nd, Fe, and B, at least a portion of the grain boundaries contains an ROC phase, the ROC phase includes a rare earth element R, O, and C, the concentration of each of R, O, and C in the ROC phase is higher compared to the main phase grains, the permanent magnet 2 comprises a surface layer portion 21 and a central portion 22, the surface layer portion 21 is positioned on the surface side of the permanent magnet 2, the central portion 22 is positioned on the inner side of the permanent magnet 2, the proportion of the area of the ROC phase occupying in a cross-section of the surface layer portion 21 is S1 %, the proportion of the area of the ROC phase occupying in a cross-section of the central portion 22 is S2%, and S1 is higher than S2.

A permanent magnet 2 includes Nd, Fe, and B, the permanent magnet 2 contains a plurality of main phase grains; and grain boundaries positioned between the main phase grains, the main phase grains include Nd, Fe, and B, at least a portion of the grain boundaries contains an ROC phase, the ROC phase includes a rare earth element R, O, and C, the concentration of each of R, O, and C in the ROC phase is higher compared to the main phase grains, the permanent magnet 2 comprises a surface layer portion 21 and a central portion 22, the surface layer portion 21 is positioned on the surface side of the permanent magnet 2, the central portion 22 is positioned on the inner side of the permanent magnet 2, the proportion of the area of the ROC phase occupying in a cross-section of the surface layer portion 21 is S1 %, the proportion of the area of the ROC phase occupying in a cross-section of the central portion 22 is S2%, and S1 is higher than S2.

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m to 2.8 m. The R-T-B based permanent magnet contains at least C and Ga in addition to R, T, and B. B is contained at 0.71 mass % to 0.86 mass %. C is contained at 0.13 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.80 mass %. A formula (1) of 0.14[C]/([B]+[C])0.30 is satisfied, where [B] is a B content represented by atom %, and [C] is a C content represented by atom %.

An R-T-B based permanent magnet includes main phase grains composed of R.sub.2T.sub.14B type compound. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. An average grain size of the main phase grains is 0.8 m to 2.8 m. The R-T-B based permanent magnet contains at least C and Ga in addition to R, T, and B. B is contained at 0.71 mass % to 0.86 mass %. C is contained at 0.13 mass % to 0.34 mass %. Ga is contained at 0.40 mass % to 1.80 mass %. A formula (1) of 0.14[C]/([B]+[C])0.30 is satisfied, where [B] is a B content represented by atom %, and [C] is a C content represented by atom %.

This disclosure is directed to sintered bodies comprising grains and a grain boundary composition, wherein: (a) the grains comprise a composition substantially represented by a formula G.sub.2M.sub.14B, where G is Nd, Dy, Pr, Tb, or a combination thereof, and M is Co, Fe, Ni, or a combination thereof, wherein the grains are optionally doped with one or more rare earth elements; and (b) the grain boundary composition is an alloy composition substantially represented by the formula: Nd.sub.8.5-12.5Dy.sub.35-45Co.sub.32-41Cu.sub.3-6.5Fe.sub.1.5-5, wherein the subscript values are atom percent relative to the total composition of the the alloy composition. Corresponding populations of particles are also disclosed

To provide a rare earth magnet ensuring excellent magnetic anisotropy while reducing the amount of Nd, etc., and a manufacturing method thereof. A rare earth magnet comprising a crystal grain having an overall composition of (R2.sub.(1-x)R1.sub.x).sub.yFe.sub.100-y-w-z-vCo.sub.wB.sub.zTM.sub.v (wherein R2 is at least one of Nd, Pr, Dy and Tb, R1 is an alloy of at least one or two or more of Ce, La, Gd, Y and Sc, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x<1, y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2), wherein the average grain size of the crystal grain is 1,000 nm or less, the crystal grain consists of a core and an outer shell, the core has a composition of R1 that is richer than R2, and the outer shell has a composition of R2 that is richer than R1.