RARE EARTH PERMANENT MAGNET MATERIAL, RAW MATERIAL COMPOSITION,PREPARATION METHOD, APPLICATION, AND MOTOR

Abstract

A rare earth permanent magnet material, a raw material composition, a preparation method, an application, and a motor. The present rare earth permanent magnet material comprises the following ingredients in mass percentage: R 28.5-33.0 wt. %; RH>1.5 wt. %; Cu 0-0.08 wt. %, but not 0 wt. %; Co 0.5-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; and the remainder being Fe and unavoidable impurities. The R-T-B system permanent magnet material has excellent properties and, under the condition that the content of heavy rare earth elements in the permanent magnetic material is 3.0-4.5 wt. %, Br≥12.78 kGs and Hcj≥29.55 kOe; under the condition that the content of heavy rare earth elements in the permanent magnet material is 1.5-2.5 wt. %, Br≥13.06 kGs and Hcj≥26.31 kOe.

Claims

1. A R-T-B based permanent magnet material, wherein, the R-T-B based permanent magnet material comprises the following components in mass percentage: R: 28.5-33.0 wt. %; RH: >1.5 wt. %; Cu: 0-0.08 wt. %, but not 0 wt. %; Co: 0.5-2.0 wt. %; Ga: 0.05-0.30 wt. %; B: 0.95-1.05 wt. %; and the remainder being Fe and unavoidable impurities; wherein: R is a rare earth element and comprises at least Nd and RH; and RH is a heavy rare earth element.

2-11. (canceled)

12. The R-T-B based permanent magnet material according to claim 1, wherein, the R-T-B based permanent magnet material comprises R.sub.2T.sub.14B grains and grain boundary phase among R.sub.2T.sub.14B grains, the composition of the grain boundary phase is R.sub.x—(B.sub.1-a-b-c—Ga.sub.a—Cu.sub.b-T.sub.c).sub.y, wherein: T is Fe and Co, 2b<a<3.5b, 1/2c<a+b, 50 at %<x<65 at %, 35 at %<y<50 at %, and at % refers to the atomic percentage of each element in the grain boundary phase.

13. The R-T-B based permanent magnet material according to claim 12, wherein, a is 0.23-0.24, and the a refers to the atomic ratio of Ga in the elements of “B, Ga, Cu, Fe and Co”; or, b is 0.1-0.115, and the b refers to the atomic ratio of Cu in the elements of “B, Ga, Cu, Fe and Co”; or, c is 0.64-0.65, and the c refers to the atomic ratio of “Fe and Co” in the elements of “B, Ga, Cu, Fe and Co”.

14. The R-T-B based permanent magnet material according to claim 12, wherein, the R.sub.x—(B.sub.1-a-b-c—Ga.sub.a—Cu.sub.b-T.sub.c).sub.y is R.sub.55.6—(B.sub.0.01—Ga.sub.0.235—Cu.sub.0.115-T.sub.0.64).sub.44.4, R.sub.56.9—(B.sub.0.02—Ga.sub.0.23—Cu.sub.0.11-T.sub.0.64).sub.43.1, R.sub.59—(B.sub.0.02—Ga.sub.0.24—Cu.sub.0.1-T.sub.0.64).sub.41, R.sub.59.1—(B.sub.0.02—Ga.sub.0.23—Cu.sub.0.11-T.sub.0.64).sub.40.9, R.sub.56.7—(B.sub.0.02—Ga.sub.0.23—Cu.sub.0.1-T.sub.0.65).sub.43.3, R.sub.57—(B.sub.0.02—Ga.sub.0.23—Cu.sub.0.1-T.sub.0.65).sub.43, R.sub.58.6—(B.sub.0.02—Ga.sub.0.23—Cu.sub.0.11-T.sub.0.64).sub.41.4 or R.sub.59.5—(B.sub.0.023—Ga.sub.0.23—Cu.sub.0.103-T.sub.0.644).sub.40.5.

15. The R-T-B based permanent magnet material according to claim 1, wherein, R further comprises Pr.

16. The R-T-B based permanent magnet material according to claim 1, wherein, RH is selected from the group consisting of Dy and Tb; or, RH comprises Tb, the content of Tb is 1.5-4.5 wt. %; or, RH comprises Dy, the content of Dy is 0.45-1.0 wt. %; and the percentage refers to mass percentage in the R-T-B based permanent magnet material.

17. The R-T-B based permanent magnet material according to claim 1, wherein, the content of Cu is 0.01-0.08 wt. %, 0.04-0.08 wt. % or 0.05-0.08 wt. %, and the percentage refers to mass percentage in the R-T-B based permanent magnet material.

18. The R-T-B based permanent magnet material according to claim 1, wherein, the content of Ga is 0.05 or 0.1-0.3 wt. %, and the percentage refers to mass percentage in the R-T-B based permanent magnet material.

19. The R-T-B based permanent magnet material according to claim 1, wherein, in the R-T-B based permanent magnet material, the R-T-B based permanent magnet material comprises the following components: R 28.5-32.0 wt. %; RH 3.0-4.5 wt. %; Cu 0-0.08 wt. % but not 0 wt. %; Co 1.0-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities; and the percentage refers to mass percentage in the R-T-B based permanent magnet material; or, the R-T-B based permanent magnet material comprises the following components: R 28.5-32.0 wt. %; RH 3.2-4.5 wt. %; Cu 0.04-0.08 wt. %; Co 1.0-2.0 wt. %; Ga 0.10-0.30 wt. %; B 0.95-1.0 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the R-T-B based permanent magnet material; or, the R-T-B based permanent magnet material comprises the following components: Nd 24.4-28.0 wt. %; Tb 3.0-4.0 wt. %; Dy 0.5-1.0 wt. %; Cu 0.01-0.08 wt. %; Co 1.0-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the R-T-B based permanent magnet material; or, the R-T-B based permanent magnet material comprises the following components: R 30.5-33.0 wt. %; RH >1.5 wt. %; Cu 0-0.08 wt. % but not 0 wt. %; Co 0.78-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the R-T-B based permanent magnet material; or, the R-T-B based permanent magnet material comprises the following components: R 30.5-33.0 wt. %; RH 1.5-2.5 wt. %; Cu 0.04-0.08 wt. %; Co 0.78-1.6 wt. %; Ga 0.10-0.30 wt. %; B 0.95-1.0 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the R-T-B based permanent magnet material; or, the R-T-B based permanent magnet material comprises the following components: Nd 28.0-30.5 wt. %; Tb 1.5-2.5 wt. %; Dy 0-0.5 wt. %; Cu 0.01-0.08 wt. %; Co 0.78-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the R-T-B based permanent magnet material.

20. An application of the R-T-B based permanent magnet material according to claim 1 as an electronic component in a motor.

21. A motor, wherein, the motor comprises the R-T-B based permanent magnet material according to claim 1.

22. A raw material composition of R-T-B based permanent magnet material, wherein, the raw material composition of an R-T-B based permanent magnet material comprises the following components in mass percentage: R: 28.5-32.5 wt. %; RH: >1.2 wt. %; Cu: 0-0.08 wt. %, but not 0 wt. %; Co: 0.5-2.0 wt. %; Ga: 0.05-0.30 wt. %; B: 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities; wherein: R is a rare earth element and comprises at least Nd and RH; RH is a heavy rare earth element.

23. The raw material composition of R-T-B based permanent magnet material according to claim 22, wherein, R further comprises Pr; or, RH is selected from the group consisting of Dy and Tb; or, RH comprises Tb, the content of Tb is 1.2-4.5 wt. %, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, RH comprises Dy, the content of Dy is 0-0.5 wt. %; or, the content of Cu is 0.01-0.08 wt. %, 0.04-0.08 wt. % or 0.05-0.08 wt. %, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the content of Ga is 0.05 or 0.1-0.3 wt. %, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material.

24. The raw material composition of R-T-B based permanent magnet material according to claim 22, wherein, the raw material composition of R-T-B based permanent magnet material comprises the following components: R 28.5-31.5 wt. %; RH 3.0-4.5 wt. %; Cu 0-0.08 wt. %, but not 0 wt. %; Co 1.0-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities; and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the raw material composition of R-T-B based permanent magnet material comprises the following components: R 28.5-31.5 wt. %, RH 3.2-4.5 wt. %, Cu 0.04-0.08 wt. %, Co 1.0-2.0 wt. %, Ga 0.10-0.30 wt. % and B 0.95-1.0 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the raw material composition of R-T-B based permanent magnet material comprises the following components: Nd 24.5-28.0 wt. %, Tb 3.0-4.0 wt. %, Dy 0-0.5 wt. %, Cu 0.01-0.08 wt. %, Co 1.0-2.0 wt. %, Ga 0.05-0.30 wt. % and B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the raw material composition of R-T-B based permanent magnet material comprises the following components: R 30.5-32.5 wt. %; RH>1.2 wt. %; Cu 0-0.08 wt. % but not 0 wt. %; Co 0.8-2.0 wt. %; Ga 0.05-0.30 wt. %; B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the raw material composition of R-T-B based permanent magnet material comprises the following components: R 30.5-32.5 wt. %, RH 1.5-2.0 wt. %, Cu 0.04-0.08 wt. %, Co 0.8-1.6 wt. %, Ga 0.10-0.30 wt. % and B 0.95-1.0 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the raw material composition of R-T-B based permanent magnet material comprises the following components: Nd 28.5-30.5 wt. %, Tb 1.5-2.0 wt. %, Dy 0-0.5 wt. %, Cu 0.01-0.08 wt. %, Co 0.8-2.0 wt. %, Ga 0.05-0.30 wt. % and B 0.95-1.05 wt. %; the remainder being Fe and unavoidable impurities, and the percentage refers to mass percentage in the raw material composition of R-T-B based permanent magnet material.

25. A preparation method for an R-T-B based permanent magnet material, wherein, the preparation method for the R-T-B based permanent magnet material comprises the following steps: molten liquid of the raw material composition of R-T-B based permanent magnet material according to claim 22 is subjected to casting, decrepitation, pulverization, forming, sintering and grain boundary diffusion treatment, and the R-T-B based permanent magnet material is obtained; wherein: the sintering is carried out sequentially in the following steps: first stage sintering, second stage sintering and cooling; the temperature of the first stage sintering is ≤1040° C.; the second stage sintering is carried out at an increased temperature on the basis of the first stage sintering with a temperature difference of ≥5-10° C., the rate of temperature increase is ≥5° C./min, and the time of the second stage sintering is ≤1 h; the rate of cooling is ≥7° C./min and the end point of cooling is ≤100° C.

26. The preparation method for an R-T-B based permanent magnet material according to claim 25, wherein, the molten liquid of the raw material composition of R-T-B based permanent magnet material is prepared according to the following method: melting in a high frequency vacuum induction melting furnace; or, the process of the casting is carried out according to the following step: in an Ar gas atmosphere, cooling at a rate of 10.sup.2° C./sec-10.sup.4° C./sec; or, the process of the decrepitation is carried out according to the following steps: hydrogen absorption, dehydrogenation and cooling treatment; or, the method of forming is a magnetic field forming method or a hot pressing and heat deformation method; or, preheating is further carried out before the first stage sintering, the temperature of the preheating is 300-600° C.; the time of the preheating is 1-2 h; or, the temperature of the first stage sintering is 1000-1030° C.; or, the time of the first stage sintering is ≥2 h; or, in the second stage sintering, the temperature difference is ≥5-10° C. and ≤20° C.; or, the time of the second stage sintering is 1 h; or, in the process of sintering, the rate of cooling is 10° C./min; or, in the process of sintering, the end point of cooling is 100° C.; or, Ar gas is introduced before the cooling to bring the air pressure to 0.1 MPa; or, a heat treatment is further carried out after the grain boundary diffusion treatment

27. The preparation method for an R-T-B based permanent magnet material according to claim 25, wherein, the grain boundary diffusion treatment is carried out in the following step: a substance containing Dy or Tb is attached to the surface of the R-T-B based permanent magnet material by vaporizing, coating or sputtering, and diffusion heat treatment is carried out; the temperature of the diffusion heat treatment is 850-980° C., the time of the diffusion heat treatment is 12-48 h.

28. An R-T-B based permanent magnet material prepared by the preparation method of the R-T-B based permanent magnet material according to claim 25.

29. An application of the R-T-B based permanent magnet material according to claim 28 as an electronic component in a motor.

30. A motor, wherein, the motor comprises the R-T-B based permanent magnet material according to claim 28.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0139] FIG. 1 shows the R.sub.x—(B.sub.1-a-b-c—Ga.sub.a—Cu.sub.b-T.sub.c).sub.y intergranular phase formed by the elements Nd, B, Ga, Co and Cu at the grain boundaries in the magnet prepared in Example 2.

[0140] FIG. 2 shows the magnet prepared in Example 2, wherein the position marked by number 1 can be used as an analysis point for detection of grain boundary phase composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0141] 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 examples are selected according to conventional methods and conditions, or according to the product specification. In the following tables, wt. % refer to the mass percentage of the components in the raw material composition of R-T-B based permanent magnet material, “/” indicates that the element is not added. “Br” refers to remanence, “Hcj” refers to intrinsic coercivity.

Example 1

[0142] The R-T-B based permanent magnet material was prepared as follows.

[0143] (1) Melting process: according to the formulation shown in Example 1 in Table 1, the prepared raw materials were put into a crucible made of alumina and vacuum melted in a high-frequency vacuum induction melting furnace and in a vacuum of 5×10.sup.−2 Pa at a temperature of 1500° C. or less.

[0144] (2) Casting process: after vacuum melting, Ar gas was introduced into the melting furnace to make the air pressure reach 55,000 Pa, then casting was carried out, and cooled at a cooling rate of 10.sup.2° C./s−10.sup.4° C./s to obtain a quench alloy.

[0145] (3) Hydrogen decrepitation process: the furnace for hydrogen decrepitation where the quench alloy was placed was evacuated at room temperature, and then hydrogen gas of 99.9% purity was introduced into the furnace for hydrogen decrepitation to maintain the hydrogen pressure at 0.15 MPa; after sufficient hydrogen absorption, it was sufficiently dehydrogenated by heating up while vacuum-pumping; then it was cooled and the powder after hydrogen decrepitation was taken out.

[0146] (4) Micro-pulverization process: the powder after decrepitation was pulverized by jet mill for 3 hours under nitrogen atmosphere with oxidizing gas content of 150 ppm or less and under the condition of the pressure of 0.38 MPa in the pulverization chamber, and fine powder was obtain. The oxidizing gas refers to oxygen or moisture.

[0147] (5) Zinc stearate was added to the powder after jet mill pulverization, and the addition amount of zinc stearate was 0.12% by weight of the mixed powder, and then it was mixed thoroughly with a V-mixer.

[0148] (6) Magnetic field forming process: a rectangular oriented magnetic field forming machine was used to conduct primary forming of the above-mentioned powder with zinc stearate into a cube with sides of 25 mm in an orientation magnetic field of 1.6T and a forming pressure of 0.35 ton/cm.sup.2; after the primary forming, it was demagnetized in a magnetic field of 0.2T. In order to prevent the formed body after the primary forming from contacting with air, it was sealed, and then secondary forming was carried out at a pressure of 1.3 ton/cm.sup.2 using a secondary forming machine (isostatic forming machine).

[0149] (7) Sintering process: each formed body was moved to a sintering furnace for sintering, the sintering was maintained under a vacuum of 5×10.sup.−3 Pa and at a temperature of/300° C. and 600° C. for 1 hour, respectively; then sintered at a temperature of 1030° C. for 3 hours, then sintered at a temperature of 1040° C. for hours; and then Ar gas was introduced to make the air pressure reach 0.1 MPa, and cooled at a cooling rate of 10° C./min to 100° C.

[0150] (8) Grain boundary diffusion treatment process: the sintered body was processed into a magnet with a diameter of 20 mm and a thickness of 5 mm, and the thickness direction is the magnetic field orientation direction, after the surface was cleaned, the diffusion raw materials containing Dy metal were coated onto the magnet separately, and the coated magnet was dried, and the magnet with Dy elements attached to the surface was diffusion heat treated at 850° C. for 24 hours in a high-purity Ar gas atmosphere. After the treatment, it was cooled to room temperature.

[0151] (9) Heat treatment process: the sintered body was heat treated at a temperature of 500° C.

TABLE-US-00001 TABLE 1 Formulation for the raw material compositions of the R-T-B based permanent magnet materials (wt. %) No. Nd Tb Dy Cu Co Ga B Fe Al P Sn Example 1 24.5 4 / 0.08 2 0.3 0.95 remainder / / / Example 2 26.5 3.6 / 0.06 1.6 0.2 0.98 remainder / / / Example 3 27.5 3.2 / 0.04 1.4 0.1 1 remainder / / / Example 4 28 3 0.5 0.01 1 0.05 1.05 remainder / / / Example 5 28.5 2 / 0.08 2 0.3 0.95 remainder / / / Example 6 29.7 1.8 / 0.06 1.6 0.2 0.98 remainder / / / Example 7 30.3 1.5 / 0.04 1 0.1 1 remainder / / / Example 8 30.5 1.5 0.5 0.01 0.8 0.05 1.05 remainder / / / Comparative 26.5 3.6 / 0.06 1.6 0.2 0.98 remainder 0.3 / / Example 1 Comparative 26.5 3.6 / 0.06 1.6 / 0.98 remainder / 0.2 / Example 2 Comparative 26.5 3.6 / 0.06 1.6 / 0.98 remainder / / 0.2 Example 3 Comparative 29.7 1.8 / 0.06 1.6 / 0.98 remainder / 0.2 / Example 4 Comparative 29.7 1.8 / 0.06 1.6 / 0.98 remainder / / 0.2 Example 5 Comparative 26.5 3.6 / 0 1.6 0.2 0.98 remainder / / / Example 6 Comparative 26.5 3.6 / 1 1.6 0.2 0.98 remainder / / / Example 7 Comparative 26.5 3.6 / 0.06 1.6 0.02 0.98 remainder / / / Example 8 Comparative 26.5 3.6 / 0.06 1.6 0.35 0.98 remainder / / / Example 9

Examples 2-8, Comparative Examples 1-9

[0152] The R-T-B based permanent magnet materials corresponding to Examples 2-8 and Comparative Examples 1-9 were prepared according to the formulations shown in Table 1, wherein, the preparation processes in Examples 2-4, Comparative Examples 1-3, and Comparative Examples 6-9 were the same as Example 1.

[0153] The preparation processes in Examples 5-8 and Comparative Examples 4-5 were the same as Example 1 except for the following differences: the process of grain boundary diffusion treatment: the sintered body was processed into a magnet with a diameter of 20 mm and a thickness of 5 mm, and the direction of the thickness is the direction of magnetic field orientation; after the surface was cleaned, the diffusion raw materials containing Tb metal were coated on the magnet through a full spray, respectively, and the coated magnet was dried; then in a high-purity Ar gas atmosphere, the magnet with Tb elements attached to the surface was diffusion heat treated at 850° C. for 24 hours. After the treatment, it was cooled to room temperature.

Comparative Examples 10-11

[0154] The raw materials of Example 2 were taken, and the preparation was carried out according to the process conditions shown in Table 2, other process conditions are the same as Example 2.

TABLE-US-00002 TABLE 2 Second stage sintering Cooling Composition of First stage sintering Heating Temperature R.sub.x − (B.sub.1−a−b−c − Temperature Time Temperature rate Time Rate of end Ga.sub.a − Cu.sub.b − T.sub.c).sub.y No. ° C. h ° C. ° C./min h ° C./min point ° C. (at %) Example 2 1030 3 1040 10 1 10 100 R.sub.56.9 − (B.sub.0.02 − Ga.sub.0.23 − Cu.sub.0.11 − T.sub.0.64).sub.43.1 Comparative 1045 4 — — — 5 100 R.sub.73.3 − (Ga.sub.0.03 − Example 10 Cu.sub.0.08 − T.sub.0.89).sub.26.7 Comparative 1030 4 — — — 5 100 R.sub.55.1 − (Ga.sub.0.16 − Example 11 Cu.sub.0.05 − T.sub.0.79).sub.44.9

[0155] As shown in Table 2, the required grain boundary phase was not generated in the permanent magnet material prepared by using only one-stage sintering at high temperature or only one-stage sintering at low temperature, and the B at the grain boundary was not diffusely distributed, but formed a B-rich phase which was not conducive to magnetic properties, which reduced the performance of the permanent magnet material.

Effectiveness Example

[0156] (1) Grain Boundary Structure of Magnets

[0157] The magnetic properties and compositions of the R-T-B based permanent magnet materials prepared in the Examples and the Comparative Examples were measured, and the grain boundary structures of the magnets were observed by FE-EPMA.

[0158] FE-EPMA inspection: the vertical orientation surfaces of the permanent magnet material were polished and inspected using a field emission electron probe microanalyzer (FE-EPMA) (Japan Electronics Company (JEOL), 8530F). The distribution of Ga, Cu, T(Fe+Co), R(Nd+Tb+Dy), B and other elements in the magnet was first determined by FE-EPMA face scan (as shown in FIG. 1), and then the content of Cu, Ga and other elements in the key phase was determined by FE-EPMA single-point quantitative analysis (e.g., the analysis point shown in FIG. 2), with the test conditions of accelerating voltage 15 kv and probe beam current 50 nA.

[0159] The results of FE-EPMA inspection are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Composition of R.sub.x − (B.sub.1−a−b−c − Ga.sub.a − Cu.sub.b− T.sub.c).sub.y (at %) No. Grain boundary phase R B Ga Cu T(Fe + Co) Example 1 R.sub.55.6 − (B.sub.0.01 − Ga.sub.0.235 − Cu.sub.0.115 − T.sub.0.64).sub.44.4 55.6 0.444 10.43 5.106 28.416 Example 2 R.sub.56.9 − (B.sub.0.02 − Ga.sub.0.23 − Cu.sub.0.11 − T.sub.0.64).sub.43.1 56.9 0.862 9.913 4.741 27.584 Example 3 R.sub.59 − (B.sub.0.02 − Ga.sub.0.24 − Cu.sub.0.1 − T.sub.0.64).sub.41 59 0.82 9.84 4.1 26.24 Example 4 R.sub.59.1 − (B.sub.0.02 − Ga.sub.0.23 − Cu.sub.0.11 − T.sub.0.64).sub.40.9 59.1 0.818 9.407 4.499 26.176 Exaniple 5 R.sub.56.7 − (B.sub.0.02 − Ga.sub.0.23 − Cu.sub.0.1 − T.sub.0.65).sub.43.3 56.7 0.866 9.959 4.33 28.145 Example 6 R.sub.57 − (B.sub.0.02 − Ga.sub.0.23 − Cu.sub.0.1 − T.sub.0.65).sub.43 57 0.86 9.89 4.3 27.95 Example 7 R.sub.58.6 − (B.sub.0.02 − Ga.sub.0.23 − Cu.sub.0.11 − T.sub.0.64).sub.41.4 58.6 0.828 9.522 4.554 26.496 Example 8 R.sub.59.5 − (B.sub.0.023 − Ga.sub.0.23 − Cu.sub.0.103 − T.sub.0.644).sub.40.5 59.5 0.932 9.315 4.172 26.082 Comparative Not generated / / / / / Example 1 Comparative Not generated / / / / / Example 2 Comparative Not generated / / / / / Example 3 Comparative Not generated / / / / / Example 4 Comparative Not generated / / / / / Example 5 Comparative R.sub.58 − (B.sub.0.01 − Ga.sub.0.2 − T.sub.0.79).sub.42 58 0.42 8.4 / 33.18 Example 6 Comparative R.sub.47 − (Ga.sub.0.15 − Cu.sub.0.57 − T.sub.0.28).sub.53 47 / 7.95 30.21 14.84 Example 7 Comparative R.sub.63 − (B.sub.0.01 − Cu.sub.0.11 − T.sub.0.88).sub.37 Example 8 61 0.37 / 4.07 32.56 Comparative R.sub.58.3 − (Ga.sub.0.26 − Cu.sub.0.08 − T.sub.0.66).sub.41.7 58.3 / 10.84 3.336 27.522 Example 9 Comparative R.sub.73.3 − (Ga.sub.0.03 − Cu.sub.0.08 − T.sub.0.89).sub.26.7 Example 10 73.3 / 0.801 2.136 23.763 Comparative R.sub.55.1 − (Ga.sub.0.16 − Cu.sub.0.05 − T.sub.0.79).sub.44.9 55.1 / 7.184 2.245 35.471 Example 11 Note: ″/″ indicates that the element is not comprised.

[0160] As shown in Table 3, both the change of species of low melting point element and the change of the amount of low melting point element have significant effects on the crystalline phase formed at the grain boundaries. When the species and/or the amount of low melting point element is not within the scope of this disclosure, it is difficult to form the R.sub.x—(B.sub.1-a-b-c—Ga.sub.a—Cu.sub.b-T.sub.c).sub.y crystalline phase at the grain boundaries that can improve the performance of the permanent magnet material.

[0161] (2) Magnetic property evaluation: the magnetic properties were tested using the NIM-10000H type BH bulk rare earth permanent magnet nondestructive measurement system in National Institute of Metrology, China.

[0162] The magnetic property test results are shown in Table 4 below.

TABLE-US-00004 TABLE 4 Br Temperature coefficient No. RH (wt %) Br (kGs) Hcj (kOe) 100° C. Example 1 4.48 14.23 29.55 0.10 Example 2 4.13 13.51 31.34 0.10 Example 3 3.7 13.32 30.87 0.10 Example 4 3.98 12.78 32.53 0.10 Comparative 4.13 13.21 28.83 0.11 Example 1 Comparative 4.12 13.30 24.57 0.12 Example 2 Comparative 4.15 13.02 23.59 0.13 Example 3 Comparative 4.15 13.51 26.22 0.11 Example 6 Comparative 4.07 13.25 25.60 0.11 Example 7 Comparative 4.11 13.51 26.46 0.11 Example 8 Comparative 4.13 13.26 28.11 0.11 Example 9 Comparative 4.13 13.46 27.10 0.11 Example 10 Comparative 4.13 13.36 29.48 0.11 Example 11 Example 5 2.3 14.10 26.39 0.11 Example 6 2.25 13.64 27.40 0.11 Example 7 1.99 13.60 26.31 0.11 Example 8 2.5 13.06 28.47 0.11 Comparative 2.1 13.43 24.32 0.12 Example 4 Comparative 2.12 13.11 21.14 0.13 Example 5

[0163] As shown in Table 4, the R-T-B based permanent magnet material in the present disclosure has excellent performance with Br12.78 kGs and Hcj29.55 kOe under the condition that the content of heavy rare earth elements in permanent magnet material is 3.0-4.5 wt. %; as well as Br≥13.06 kGs and Hcj≥26.31 kOe under the condition that the content of heavy rare earth elements in permanent magnet material is 1.5-2.5 wt. %, which can achieve the simultaneous improvement of Br and Hcj.

[0164] Combined with Table 3, it can be seen that the formation of R.sub.x—(B.sub.1-a-b-c—Ga.sub.a—Cu.sub.b-T.sub.c).sub.y crystalline phase is beneficial to the improvement of the performance of the permanent magnet material, the inventors speculate that the crystalline phase may improve the grain boundary morphology by increasing the wettability of the grain boundary, and provide a continuous grain boundary channel for the diffusion process, thus the improvement of Hcj is achieved and the permanent magnet material with high Brand high Hcj is further obtained.

[0165] (3) Component determination: the components were determined using high-frequency inductively coupled plasma emission spectrometer (ICP-OES). The following Table 5 shows the results of the component determination.

TABLE-US-00005 TABLE 5 Results of the component determination (wt. %) No. Nd Tb Dy Cu Co Ga B Fe Al P Sn Example 1 24.46 3.98 0.50 0.07 2.00 0.30 0.95 remainder / / / Example 2 26.40 3.61 0.52 0.06 1.58 0.20 0.98 remainder / / / Example 3 27.39 3.19 0.51 0.05 1.39 0.10 0.99 remainder / / / Example 4 27.94 2.99 0.99 0.01 1.00 0.05 1.04 remainder / / / Example 5 28.36 2.30 / 0.08 2.00 0.30 0.95 remainder / / / Example 6 29.58 2.25 / 0.06 1.60 0.20 0.98 remainder / / / Example 7 30.24 1.99 / 0.05 0.99 0.10 0.99 remainder / / / Example 8 30.36 2.01 0.49 0.01 0.79 0.05 1.04 remainder / / / Comparative 26.39 3.60 0.53 0.06 1.60 0.20 0.98 remainder 0.29 / / Example 1 Comparative 26.41 3.60 0.52 0.06 1.58 / 0.98 remainder / 0.20 / Example 2 Comparative 26.37 3.60 0.55 0.06 1.60 / 0.97 remainder / / 0.20 Example 3 Comparative 29.55 2.10 / 0.06 1.59 / 0.98 remainder / 0.20 / Example 4 Comparative 29.60 2.12 / 0.06 1.60 / 0.98 remainder / / 0.20 Example 5 Comparative 26.40 3.62 0.53 0.00 1.59 0.20 0.98 remainder / / / Example 6 Comparative 26.36 3.58 0.49 0.99 1.60 0.20 0.97 remainder / / / Example 7 Comparative 26.39 3.60 0.51 0.05 1.60 0.02 0.98 remainder / / / Example 8 Comparative 26.42 3.59 0.54 0.06 1.58 0.35 0.98 remainder / / / Example 9 Note: ″/″indicates that the element is not comprised.