NEODYMIUM-IRON-BORON MAGNET MATERIAL, RAW MATERIAL COMPOSITION PREPARATION METHOD, AND APPLICATION

Abstract

Provided are a neodymium-iron-boron magnet material, raw material composition, preparation method, and application. The raw material composition of the neodymium-iron-boron magnet material comprises the following mass content components: R: 28-33%; R is a rare earth element, R comprises R1 and R2; R1 is a rare earth element added during smelting, and R1 comprises Nd and Dy; R2 is a rare earth element added during grain boundary diffusion, R2 comprises Tb, the content of R2 is 0.2%-1%; Co: <0.5%, but not 0; M: ≤0.4%, but not 0, and M is one or more of Bi, Sn, Zn, Ga, In, Au, and Pb; Cu: ≤0.15%, but not 0; B: 0.9-1.1%; Fe: 60-70%; the percentage is the mass percentage of the mass of each component to the total mass of the raw material composition. The neodymium-iron-boron magnet material has high remanence, coercivity, and good thermal stability.

Claims

1. A raw material composition of neodymium-iron-boron magnet material, which comprises the following components by mass percentage: R: 28-33%; R is rare earth element, which comprises R1 and R2; R1 is rare earth element added during smelting, which comprises Nd and Dy; R2 is rare earth element added during grain boundary diffusion, which comprises Tb, the content of R2 is 0.2%-1%; Co<0.5%, but not 0; M≤0.4%, but not 0, M is one or more of Bi, Sn, Zn, Ga, In, Au, and Pb; Cu≤0.15%, but not 0; B: 0.9-1.1%; Fe: 60-70%; the percentage is the mass percentage of the mass of each component to the total mass of the raw material composition.

2. The raw material composition according to claim 1, wherein, the content of Co is 0.05-0.45%, the percentage is the mass percentage to the total mass of the raw material composition.

3. The raw material composition according to claim 1, wherein, the raw material composition comprises the following components by mass percentage: R: 29.5-32.6%; R comprises R1 and R2; R1 is rare earth element added during smelting, which comprises Nd and Dy; R2 is rare earth element added during grain boundary diffusion, which comprises Tb, the content of R2 is 0.2%-0.9%; Co: 0.05-0.45%; the content of M is 0.35% or less, but not 0, M is one or more of Ga, Bi, and Zn; Cu: 0.05-0.15%; B: 0.97-1.1%; Fe: 65-69.5%; the percentage is the mass percentage of the mass of each component to the total mass of the raw material composition; or, the raw material composition of neodymium-iron-boron magnet material comprises the following components by mass percentage: R: 29.5-30.5%; R comprises R1 and R2, R1 is rare earth element added during smelting, which comprises Nd and Dy; R2 is rare earth element added during grain boundary diffusion, which comprises Tb, the content of R2 is 0.2%-0.8%; Co: 0.1-0.4%; M: 0.05-0.35%, M is one or more of Ga, Bi, and Zn; Cu: 0.05-0.08%; B: 0.99-1.1%; Fe: 65.5-69%; the percentage is the mass percentage of the mass of each component to the total mass of the raw material composition.

4. A preparation method for neodymium-iron-boron magnet material, which employs the raw material composition according to claim 1; the preparation method is the diffusion method, wherein, R1 elements are added during smelting step, and R2 elements are added during grain boundary diffusion step.

5. The preparation method according to claim 4, wherein, the preparation method comprises the following steps: the elements other than R2 in the raw material composition of neodymium-iron-boron magnet material are subjected to smelting, powdering, forming, sintering to obtain a sinter, and then the mixture of the sinter and R2 is subjected to grain boundary diffusion.

6. A neodymium-iron-boron magnet material, which is prepared by the preparation method according to claim 4.

7. A neodymium-iron-boron magnet material, which comprises the following components by mass percentage: R: 28-33%; R comprises R1 and R2, R1 comprises Nd and Dy, R2 comprises Tb, the content of R2 is 0.2%-1%; Co: <0.5%, but not 0; M: ≤0.4%, but not 0, M is one or more of Bi, Sn, Zn, Ga, In, Au, and Pb; Cu: ≤0.15%, but not 0; B: 0.9-1.1%; Fe: 60-70%; the percentage is the mass percentage of the mass of each component to the total mass of neodymium-iron-boron magnet material; the neodymium-iron-boron magnet material comprises Nd.sub.2Fe.sub.14B grains and their shells, and two-grain intergranular boundary and grain boundary triangle region adjoining to the Nd.sub.2Fe.sub.14B grains; wherein, the heavy rare earth elements in R1 are distributed in Nd.sub.2Fe.sub.14B grains, R2 is mainly distributed in the shell, two-grain intergranular boundary and grain boundary triangle region, the area proportion of the grain boundary triangle region is 1.9-3.15%; the continuity of the two-grain intergranular boundary is 96% or more; the proportion of the mass of C and O in the grain boundary triangle region is 0.4-0.5%, the proportion of the mass of C and O in the two-grain intergranular boundary is 0.3-0.45%.

8. The neodymium-iron-boron magnet material according to claim 7, wherein, the two-grain intergranular boundary further comprises a phase with the chemical composition of R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z; wherein, R in the R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z comprises one or more of Nd, Dy, and Tb; M is one or more of Bi, Sn, Zn, Ga, In, Au, and Pb; x is 42-44; y is 0.2-0.4; z is 0.2-0.45; or, the content of Co is 0.05-0.45%, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material.

9. The neodymium-iron-boron magnet material according to claim 7, wherein, the neodymium-iron-boron magnet material comprises the following components by mass percentage: R: 29.5-32.6%; R comprises R1 and R2; R1 is a earth element added during smelting, which comprises Nd and Dy; R2 is a earth element added during grain boundary diffusion, which comprises Tb, the content of R2 is 0.2%-0.9%; Co: 0.05%-0.45%; the content of M is 0.35% or less, but not 0, M is one or more of Ga, Bi, and Zn; Cu: 0.05-0.15%; B: 0.97-1.05%; Fe: 65-69.5%; the percentage is the mass percentage of the mass of each component to the total mass of the neodymium-iron-boron magnet material; the neodymium-iron-boron magnet material comprises Nd.sub.2Fe.sub.14B grains and their shells, and two-grain intergranular boundary and grain boundary triangle region adjoining to the Nd.sub.2Fe.sub.14B grains; wherein, the heavy rare earth elements in R1 are distributed in Nd.sub.2Fe.sub.14B grains, R2 is mainly distributed in the shell, two-grain intergranular boundary and grain boundary triangle region, the area proportion of the grain boundary triangle region is 1.98-2.78%; the continuity of the two-grain intergranular boundary is 97% or more; the mass proportion of C and O in the grain boundary triangle region is 0.41-0.49%, the mass proportion of C and O in the two-grain intergranular boundary is 0.32-0.41%; the two-grain intergranular boundary comprises a new phase with the chemical composition of R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z; wherein, R in the R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z comprises one or more of Nd, Dy and Tb; M is one or more of Ga, Bi, and Zn; x is 42-44; y is 0.2-0.4; z is 0.2-0.45; the ratio of the area of the new phase in the two-grain intergranular boundary to total area of the two-grain intergranular boundary is 0.24-2.2%; or, the neodymium-iron-boron magnet material comprises the following components by mass percentage: R: 29.5-30.5; R comprises R1 and R2; R1 is rare earth element added during smelting, which comprises Nd and Dy; R2 is rare earth element added during grain boundary diffusion, which comprises Tb, the content of R2 is 0.2%-0.8%; Co: 0.1%-0.4%; M: 0.05%-0.35%, M is one or more of Ga, Bi, and Zn; Cu: 0.05-0.08%; B: 0.99-1.1%; Fe: 65.5-69%; the percentage is the mass percentage of the mass of each component to the total mass of the neodymium-iron-boron magnet material; the neodymium-iron-boron magnet material comprises Nd.sub.2Fe.sub.14B grains and their shells, and two-grain intergranular boundary and grain boundary triangle region adjoining to the Nd.sub.2Fe.sub.14B grains; wherein, the heavy rare earth elements in R1 are distributed in Nd.sub.2Fe.sub.14B grains, R2 is mainly distributed in the shell, two-grain intergranular boundary and grain boundary triangle region, the area proportion of the grain boundary triangle region is 1.98-2.62%; the continuity of grain boundary of the neodymium-iron-boron magnet material is 98% or more; the mass proportion of C and O in the grain boundary triangle region is 0.41-0.45%, the mass proportion of C and O in the two-grain intergranular boundary is 0.34-0.41%; the two-grain intergranular boundary comprises a new phase with the chemical composition of R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z; wherein, R in the R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z comprises one or more of Nd, Dy, and Tb; M is one or more of Ga, Bi, and Zn; x is 42.33-43.57; y is 0.23-0.35; z is 0.27-0.41; the ratio of the area of the new phase in the two-grain intergranular boundary to total area of the two-grain intergranular boundary is 0.5-2.14%.

10. An application of the neodymium-iron-boron magnet material according to claim 7 in the preparation of magnet steel.

11. The raw material composition according to claim 1, wherein, the content of Nd in R1 of the raw material composition is 28.5-32.5%, the percentage is the mass percentage to the total mass of the raw material composition; or, the content of Dy in R1 is 0.3% or less, but not 0, the percentage is the mass percentage to the total mass of the raw material composition; or, R1 further comprises one or more of Pr, Ho, Tb, Gd, and Y; or, R2 is selected from the group consisting of Pr and Dy; or, the way of adding Cu comprises adding Cu during smelting or adding Cu during grain boundary diffusion.

12. The raw material composition according to claim 1, wherein, the kind of M is one or more of Zn, Ga, and Bi; or, the raw material composition further comprises Al.

13. The raw material composition according to claim 12, wherein, the content of Al is 0.3% or less, but not 0, but not 0, the percentage is the mass percentage to the total mass of the raw material composition; or, when M comprises Ga, and Ga≤0.01%, Al+Ga+Cu≤0.11% in the composition of M element, the percentage is the mass percentage to the total mass of the raw material composition.

14. The preparation method according to claim 5, wherein, the preparation method comprises the following steps: before the grain boundary diffusion further comprises coating operation of R2; or, after the grain boundary diffusion, low temperature tempering treatment is further performed.

15. The preparation method according to claim 5, wherein, the temperature of the smelting is 1300-1700° C.; the powdering process comprises hydrogen decrepitation powdering and jet milling powdering; the hydrogen decrepitation powdering comprises hydrogen absorption, dehydrogenation and cooling treatment; the temperature of the hydrogen absorption is 20-200° C., the temperature of the dehydrogenation is 400-650° C., the pressure of the hydrogen absorption is 50-600 kPa; the jet milling powdering is performed under the condition of 0.1-2 MPa, the time of the jet milling powdering is 2-4 h; the temperature of the sintering is 1000-1200° C.; the time of the sintering is 0.5-10 h; the temperature of the grain boundary diffusion is 800-1000° C.; the time of the grain boundary diffusion is 5-20 h; the temperature of the low temperature tempering treatment is 460-560° C.; and, the time of the low temperature tempering treatment is 1-3 h.

16. The neodymium-iron-boron magnet material according to claim 8, wherein, x is 42.33-43.57, y is 0.23-0.35, z is 0.27-0.41; or, the ratio of the area of the new phase in the two-grain intergranular boundary to the total area of the two-grain intergranular boundary is 0.24-2.2%.

17. The neodymium-iron-boron magnet material according to claim 8, wherein, when the content of Nd in R1 is 28.5-32.5%, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material; or, the content of Dy in R1 is 0.3% or less, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material; or, R1 further comprises one or more of Pr, Ho, Tb, Gd, and Y; or, R2 is selected from the group consisting of Pr and Dy; or, the way of adding Cu comprises adding during smelting or adding during the grain boundary diffusion.

18. The neodymium-iron-boron magnet material according to claim 17, wherein, when R2 comprises Pr, the content of Pr is 0.2% or less, but not 0, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material; or, when R2 comprises Dy, the content of Dy is 0.3% or less, but not 0, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material.

19. The neodymium-iron-boron magnet material according to claim 8, wherein, the kind of M is one or more of Zn, Ga, and Bi; or, the neodymium-iron-boron magnet material further comprises Al.

20. The neodymium-iron-boron magnet material according to claim 19, wherein, the content of Al is 0.3% or less, but not 0, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material; or, when M comprises Ga and Ga≤0.01%, Al+Ga+Cu≤0.11% in the composition of M element, the percentage is the mass percentage to the total mass of the neodymium-iron-boron magnet material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0136] FIG. 1 is an EPMA micro-structural diagram of the neodymium-iron-boron magnet material of Example 4. The point indicated by arrow 1 in the FIGURE is the new phase of R.sub.x(Fe+Co)100-x-y-zCuyMz which is contained in two-grain intergranular boundary, and the position indicated by the arrow 2 refers to the grain boundary triangle region, and the position indicated by arrow 3 refers to the Nd.sub.2Fe.sub.14B main phase.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0137] The following examples further illustrate the present disclosure, but the present disclosure is not limited thereto. Experiment methods in which specific conditions are not indicated in the following embodiments are selected according to conventional methods and conditions, or according to the product specification.

[0138] 1. The raw material composition of neodymium-iron-boron magnet material of Examples 1-9 and Comparative Examples 1-4 are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Formulations and contents (wt. %) for the raw material compositions of the neodymium-iron-boron magnet materials. R1 R2 M Nd Dy Pr Tb Pr Dy Co Ga Zn Bi Al Cu B Fe Example 1 28.6 0.05 0.1 1 / / 0.05 0.05 / / 0.1 0.05 0.99 69.01 Example 2 28.6 0.1 0.2 0.9 / / 0.05 0.1 / / / 0.05 1 69 Example 3 28.6 0.08 / 0.9 / / 0.1 0.3 / / / 0.06 1.1 68.86 Example 4 29.9 0.1 / 0.8 0.1 / 0.1 0.2 / / 0.2 0.08 0.99 67.53 Example 5 30.4 0.05 / 0.8 / 0.1 0.2 0.35 / / / 0.1 0.99 67.01 Example 6 29.9 0.1 / 0.6 / / 0.2 0.25 0.1 / 0.1 1 67.75 Example 7 29.9 0.2 / 0.6 / / 0.3 0.05 0.05 0.25 / 0.1 1.1 67.45 Example 8 30.4 0.05 / 0.3 0.2 / 0.4 / / 0.2 / 0.15 0.99 67.31 Example 9 32.1 0.3 / 0.2 / / 0.45 / / 0.08 / 0.15 1.1 65.62 Comparative Example 1 29.9 0.1 / 0.1 0.8 0.1 0.2 / / 0.2 0.08 0.99 67.53 Comparative Example 2 29.9 0.1 / 0.8 0.1 / 0.1 0.2 / / 0.2 0.25 0.99 67.36 Comparative Example 3 29.9 0.1 / 0.6 / / 0.15 / / 0.07 0.99 68.19 Comparative Example 4 29.9 0.1 / 0.8 0.1 / 0.1 0.45 / / 0.2 0.08 0.99 67.28 Note: “/” means that the element is not comprised, wt. % refers to mass percentage.

[0139] 2. The Preparation Method of the Neodymium-Iron-Boron Magnet Material of Example 1.

[0140] (1) Smelting and casting process: according to the formulation in Table 1, the prepared raw materials other than R2 (R2 in Example 4 and Example 8 was added in the form of PrCu, and the content of Cu added in the grain boundary diffusion step in Example 4 and Example 8 was 0.05 wt. % and 0.03 wt. % respectively. The content of Cu added in the smelting step in Example 4 and Example 8 was 0.03 wt. % and 0.12 wt. % respectively.) were put into a crucible made of alumina and were vacuum smelted in a high frequency vacuum smelting furnace with 0.05 Pa of vacuum at a temperature of 1500° C. Ar gas was introduced into the mid-frequency vacuum induction strip casting furnace, and the casting was carried out, and the alloy was quenched to obtain the alloy sheet.

[0141] (2) Hydrogen decrepitation powdering process: the hydrogen decrepitation furnace in which the quench alloy was placed was evacuated at room temperature, and then hydrogen with 99.9% purity was introduced into the hydrogen decrepitation furnace to maintain the hydrogen pressure at 90 kPa, after full hydrogen absorption, the temperature was raised while vacuuming to fully dehydrogenate; then cooling was carried out and the powder after hydrogen decrepitation was taken out. Herein, the temperature of hydrogen absorption was room temperature, and the temperature of dehydrogenation was 550° C.

[0142] (3) Jet milling powdering process: the powder after hydrogen decrepitation was pulverized by jet mill for 3 hours under a nitrogen atmosphere and a pressure of 0.6 MPa in the pulverization chamber to obtain a fine powder.

[0143] (4) Forming process: the powder pulverized by jet mill was formed in the strength of the magnetic field 1.5 T or more.

[0144] (5) Sintering process: Each formed body was moved into the sintering furnace for sintering, which was sintered in 0.5 Pa or less of vacuum degree and at 1030° C.-1090° C. for 2-5 h to obtain sintered body.

[0145] (6) Grain boundary diffusion process: after purifying the surface of the sintered body, R2 (For example, one or more of the alloy or fluoride of Tb, the alloy or fluoride of Dy and PrCu alloy, wherein, the Cu was added both in the smelting step and the grain boundary diffusion step.) was coated on the surface of the sintered body, and diffused with the temperature of 850° C. for 5-15 h, then cooled to room temperature, and then performed the low temperature tempering at a temperature of 460-560° C. for 1-3 h.

[0146] Parameters in the preparation method for neodymium-iron-boron magnet materials of Examples 2-9 and Comparative Examples 1˜4 were the same as Example 1.

[0147] 3. Components measurement: determine the neodymium-iron-boron magnet material of Examples 1-9 and Comparative Examples 1˜4 with high-frequency inductively coupled plasma emission spectrometer (ICP-OES). The testing results were shown in Table 2 below.

TABLE-US-00002 TABLE 2 Components and content (wt. %) of the neodymium-iron-boron magnet materials. R1 R2 M Nd Dy Pr Tb Pr Dy Co Ga Zn Bi Al Cu B Fe Example 1 28.6 0.05 0.1 1 / / 0.05 0.05 / / 0.1 0.05 0.99 69.01 Example 2 28.6 0.1 0.2 0.9 / / 0.05 0.1 / / / 0.05 1 69 Example 3 28.6 0.08 / 0.9 / / 0.1 0.3 / / / 0.06 1.1 68.86 Example 4 29.9 0.1 / 0.8 0.1 / 0.1 0.2 / / 0.2 0.08 0.99 67.53 Example 5 30.4 0.05 / 0.8 / 0.1 0.2 0.35 / / / 0.1 0.99 67.01 Example 6 29.9 0.1 / 0.6 / / 0.2 0.25 0.1 / 0.1 1 67.75 Example 7 29.9 0.2 / 0.6 / / 0.3 0.05 0.05 0.25 / 0.1 1.1 67.45 Example 8 30.4 0.05 / 0.3 0.2 / 0.4 / / 0.2 / 0.15 0.99 67.31 Example 9 32.1 0.3 / 0.2 / / 0.45 / / 0.08 / 0.15 1.1 65.62 Comparative Example 1 29.9 0.1 / 0.1 0.8 0.1 0.2 / / 0.2 0.08 0.99 67.53 Comparative Example 2 29.9 0.1 / 0.8 0.1 / 0.1 0.2 / / 0.2 0.25 0.99 67.36 Comparative Example 3 29.9 0.1 / 0.6 / / 0.15 / / 0.07 0.99 68.19 Comparative Example 4 29.9 0.1 / 0.8 0.1 / 0.1 0.45 / / 0.2 0.08 0.99 67.28 Note: “/” means that the element is not comprised, wt. % refers to mass percentage.

Effect Example 1

[0148] Neodymium-iron-boron magnet materials of Examples 1-9 and Comparative Examples 1˜4 were determined as follows:

[0149] 1. Magnetic properties determination: The sintering magnet were tested for magnetic properties by using the PFM-14 magnetic properties measuring instrument of the British Hirs company. The determined magnetic properties comprise the remanence at 20° C. and 120° C., the coercivity at 20° C. and 120° C., and the corresponding remanence temperature coefficient. Herein, the formula for calculating the remanence temperature coefficients is: (Br.sub.high temperature−Br.sub.room temperature)/(Br.sub.room temperature (high temperature-room temperature))×100%, the test results are shown in Table 3 below.

[0150] 2. FE-EPMA determination: The perpendicularly oriented surface of the neodymium-iron-boron magnet materials was polished and tested by the Field Emission Electron Probe Micro-Analyzer (FE-EPMA) (Japan Electronics Company (JEOL), 8530F). Testing the area proportion of the grain boundary triangle region, the continuity of two-grain intergranular boundary, the proportion of the mass of C and 0, and the new phase.

[0151] The continuity of the two-grain intergranular boundary was calculated based on the back scattering picture of EPMA. The proportion of the mass of C and O in the two-grain intergranular boundary and the grain boundary triangle region, and the new phase were measured by EPMA element analysis.

[0152] The area proportion (%) of the grain boundary triangle region refers to the ratio of the area of the grain boundary triangle region to the total area of “grains and grain boundaries”.

[0153] The continuity (%) of two-grain intergranular boundary refers to the ratio of the length of the phases (phase, such as rich B phase, rich rare earth phase, rare earth oxides, rare earth carbides, etc.) except the empty hole in the grain boundary to the total length of the grain boundary.

[0154] The proportion (%) of the mass of C and O in the grain boundary triangle region refers to the ratio of the mass of C and O in the grain boundary triangle region to the total mass of all elements in the grain boundary.

[0155] The proportion (%) of the mass of C and O in the two-grain intergranular boundary refers to the ratio of the mass of C and O in the two-grain intergranular boundary to the total mass of all elements in the grain boundary.

[0156] The proportion (%) of the area of the new phase in the two-grain intergranular boundary refers to the ratio of the area of the new phase in the two-grain intergranular boundary to total area of the two-grain intergranular boundary.

TABLE-US-00003 TABLE 3 The propor- The propor- The propor- tion (%) tion (%) tion (%) of the The of the of the area of continuity mass of mass of the new The (%) of the C and C and phase in 20-120° C. area two-grain O in the O in the the two- Br proportion inter- grain two-grain grain 120° C. temperature (%) of the granular boundary inter- inter- Br Hcj Br coefficient triangle boundary triangle granular granular (kGs) (kOe) (kGs) α(Br)%/° C. region phase region boundary New phase boundary Example 1 14.63 25.72 13.11 −0.104 2.51 97.72 0.49 0.38 R.sub.43(Fe + 1.25 Co).sub.56.39Cu.sub.0.29M.sub.0.32 Example 2 14.72 24.98 13.17 −0.105 1.98 96.99 0.45 0.34 R.sub.42.79(Fe + 2.14 Co).sub.56.64Cu.sub.0.23M.sub.0.34 Example 3 14.66 24.93 13.12 −0.105 2.62 97.11 0.41 0.38 R.sub.42.38(Fe + 0.97 Co).sub.56.9Cu.sub.0.35M.sub.0.37 Example 4 14.61 26.72 13.06 −0.106 2.76 97.54 0.42 0.38 R.sub.42.87(Fe + 1.06 Co).sub.56.48Cu.sub.0.31M.sub.0.34 Example 5 14.55 26.88 13.02 −0.105 2.53 97.74 0.45 0.41 R.sub.43.92(Fe + 1.33 Co).sub.55.48Cu.sub.0.28M.sub.0.32 Example 6 14.63 24.89 13.11 −0.104 2.45 97.26 0.45 0.37 R.sub.42.33(Fe + 0.54 Co).sub.57.11Cu.sub.0.29M.sub.0.27 Example 7 14.61 25.01 13.07 −0.105 2.43 97.61 0.44 0.32 R.sub.43.57(Fe + 1.56 Co).sub.55.81Cu.sub.0.26M.sub.0.36 Example 8 14.62 24.93 13.13 −0.102 2.78 97.33 0.42 0.36 R.sub.43.27(Fe + 0.63 Co).sub.56.05Cu.sub.0.27M.sub.0.41 Example 9 14.37 24.64 12.92 −0.101 3.15 98.02 0.47 0.34 R.sub.43.10(Fe + 0.24 Co).sub.56.24Cu.sub.0.34M.sub.0.32 Comparative 14.6 22.93 13.06 −0.105 3.67 96.21 0.58 0.21 x 0 Example 1 Comparative 14.51 23.17 12.96 −0.107 3.59 96.37 0.54 0.25 x 0 Example 2 Comparative 14.48 24.11 12.91 −0.108 3.88 96.19 0.51 0.24 x 0 Example 3 Comparative 14.43 24.14 12.85 −0.109 3.92 96.43 0.53 0.26 x 0 Example 4 Note: “x”means that there is no new phase with the chemical composition of R.sub.x(Fe + Co).sub.100−x−y−zCu.sub.yM.sub.z in the two-grain intergranular boundary.

[0157] From the above Table 3, it can be seen that the present invention can reach the level which is equivalent to adding a large amount of Co and heavy rare earth elements under condition of adding a small amount of heavy rare earth elements and without adding Co element. In addition, due to the high content of the rare earth in the grain boundary, C and 0 are more distributed in the grain boundary, and they exist in the form of rare earth carbides and rare earth oxides. Compared with Comparative Examples 1-4, the differences of “the mass proportion of C and O in the grain boundary triangle region” minus “the mass proportion (%) of C and O in the two-grain intergranular boundary” in the Examples 1-9 are all decrease, so it can be concluded that hybrid phases (rare earth carbides and rare earth oxides) have been transferred from the grain boundary triangle region to the two-grain intergranular boundary, which mechanically explains the reason for improvement of continuity of the two-grain intergranular boundary.

Effect Example 2

[0158] As shown in FIG. 1, it is an EPMA micro-structural diagram of the prepared neodymium-iron-boron magnet material of Example 4. The point indicated by arrow 1 in the FIGURE is the new phase R.sub.x(Fe+Co).sub.100-x-y-zCu.sub.yM.sub.z which is contained in two-grain intergranular boundary (light gray region), and the position indicated by the arrow 2 refers to the grain boundary triangle region (silver white region), and the position indicated by arrow 3 refers to the Nd.sub.2Fe.sub.14B main phase (deep gray region). Combined with the data of Table 3, it can be further seen that the region of the grain boundary triangle region is less than that of the conventional magnetic material.