NEODYMIUM-IRON-BORON MAGNETIC MATERIAL, PREPARATION METHOD THEREFOR AND APPLICATION THEREOF

Abstract

A neodymium-iron-boron magnetic material, a preparation method therefor and an application thereof. The neodymium-iron-boron magnetic material comprises the following components in percentage by mass: 29.5-31.5 wt. % of R, where RH>1.5 wt. %; 0.05-0.25 wt. % of Cu; 0.42-2.6 wt. % of Co; 0.20-0.3 wt. % of Ga; 0.25-0.3 wt. % of N; 0.46-0.6 wt. % of Al, or alternatively Al is less than or equal to 0.04 wt. % but is not 0; 0.98-1 wt. % of B; and 64-68 wt. % of Fe; wherein R is a rare-earth element and comprises Nd and RH, RH is a heavy rare-earth element and comprises Tb, and a mass ratio of Tb to Co is less than or equal to 15 but is not 0. The neodymium-iron-boron magnetic material has higher Hcj and Br, and lower absolute values of temperature coefficients of Br and Hcj.

Claims

1. A neodymium-iron-boron magnetic material, comprising, by mass percentage, the following components: 29.5-31.5 wt. % of R, with RH>1.5 wt. %, 0.05-0.25 wt. % of Cu, 0.42-2.6 wt. % of Co, 0.20-0.3 wt. % of Ga, 0.25-0.3 wt. % of N, including one or more of Zr, Nb, Hf and Ti, 0.46-0.6 wt. % of Al or Al≤0.04 wt. %, exclusive of 0 wt. %, 0.98-1 wt. % of B, 64-68 wt. % of Fe, wherein R is a rare earth element and includes at least Nd and RH, and RH is a heavy rare earth element and includes Tb; the mass ratio of Tb to Co is less than or equal to 15, exclusive of 0.

2. The neodymium-iron-boron magnetic material according to claim 1, wherein the neodymium-iron-boron magnetic material further comprises Mn.

3. The neodymium-iron-boron magnetic material according to claim 2, wherein the content of Mn is less than or equal to 0.035 wt. %, exclusive of 0 wt. %.

4. The neodymium-iron-boron magnetic material according to claim 1, wherein the neodymium-iron-boron magnetic material comprises, by mass percentage, the following components: 27-28 wt. % of Nd, 2.8-4 wt. % of Tb, 0.05-0.16 wt. % of Cu, 1.48-2.7 wt. % of Co, 0.2-0.26 wt. % of Ga, 0.25-0.3 wt. % of N, 0.46-0.5 wt. % or 0.02-0.04 wt. % of Al, 0.98-0.99 wt. % of B, and 64-66 wt. % of Fe, with the percentage referring to the mass percentage relative to the neodymium-iron-boron magnetic material; N is selected from the group consisting of Zr and Ti; Tb accounts for 9.7-13 wt. % of the total mass of Nd and Tb, and the mass ratio of Tb to Co is (1-15):1.

5. A primary alloy for preparing a neodymium-iron-boron magnetic material, wherein the composition of the primary alloy is Nd.sub.a—Fe.sub.b—B.sub.c—Tb.sub.d—Co.sub.e—Cu.sub.f—Ga.sub.g—Al.sub.x—Mn.sub.y—N.sub.h, wherein a, b, c, d, e, f, g, h, x and y refer to the mass fraction of each element in the primary alloy, a is 26-30 wt. %, b is 64-68 wt. %, c is 0.96-1.1 wt. %, d is 0.5-5 wt. %, e is 0.5-2.6 wt. %, f is 0.05-0.3 wt. %, g is 0.05-0.3 wt. %, x is less than or equal to 0.04 wt. %, exclusive of 0 wt. %, or 0.46-0.6 wt. %, y is 0-0.04 wt. %, and h is 0.2-0.5 wt. %, with the percentage referring to the mass percentage relative to the primary alloy.

6. The primary alloy according to claim 5, wherein the composition of the primary alloy is Nd.sub.a—Fe.sub.b—B.sub.c—Tb.sub.d—Co.sub.e—Cu.sub.f—Ga.sub.g—Al.sub.x—Mn.sub.y—N.sub.h, wherein a, b, c, d, e, f, g, h, x and y refer to the mass fraction of each element in the primary alloy, a is 28-29 wt. %, b is 65.5-67.5 wt. %, c is 0.98-1 wt. %, d is 1-1.5 wt. %, e is 1.4-2.6 wt. %, f is 0.05-0.16 wt. %, g is 0.1-0.25 wt. %, x is 0.02-0.04 wt. % or 0.45-0.47 wt. %, y is 0.02-0.04 wt. %, h is 0.25-0.3 wt. %, with the percentage referring to the mass percentage relative to the primary alloy.

7. An auxiliary alloy for preparing a neodymium-iron-boron magnetic material, wherein the composition of the auxiliary alloy is Nd.sub.i—Fe.sub.j—B.sub.k—Tb.sub.i—Co.sub.m—Cu.sub.n—Ga.sub.o—Al.sub.r—Mn.sub.t—N.sub.p, wherein i, j, k, l, m, n, o, p, r and t refer to the mass fraction of each element in the auxiliary alloy, i is 5-30 wt. %, j is 59-65 wt. %, k is 0.98-1 wt. %, 1 is 5-25 wt. %, m is 0.5-2.7 wt. %, n is 0.05-0.3 wt. %, o is 0.05-0.3 wt. %, r is less than or equal to 0.04 wt. %, exclusive of 0 wt. %, or 0.46-0.6 wt, t is 0-0.04 wt. %, and p is 0-0.5 wt. %, with the percentage referring to the mass percentage relative to the auxiliary alloy.

8. A method for preparing a neodymium-iron-boron magnetic material, wherein the neodymium-iron-boron magnetic material is prepared from primary alloy and the auxiliary alloy according to claim 7 by means of a dual alloy method, wherein the mass ratio of the primary alloy to the auxiliary alloy is (9-30):1; the composition of the primary alloy is Nd.sub.a—Fe.sub.b—B.sub.c—Tb.sub.d—Co.sub.e—Cu.sub.f—Ga.sub.g—Al.sub.x—Mn.sub.y—N.sub.h, wherein a, b, c, d, e, f, g, h, x and y refer to the mass fraction of each element in the primary alloy, a is 26-30 wt. %, b is 64-68 wt. %, c is 0.96-1.1 wt. %, d is 0.5-5 wt. %, e is 0.5-2.6 wt. %, f is 0.05-0.3 wt. %, g is 0.05-0.3 wt. %, x is less than or equal to 0.04 wt. %, exclusive of 0 wt. %, or 0.46-0.6 wt. %, y is 0-0.04 wt. %, and h is 0.2-0.5 wt. %, with the percentage referring to the mass percentage relative to the primary alloy.

9. A neodymium-iron-boron magnetic material obtained by the preparation method according to claim 8.

10. An application of the neodymium-iron-boron magnetic material according to claim 1 as an electronic component in a motor.

11. The neodymium-iron-boron magnetic material according to claim 1, wherein the mass percentage of RH in R is 9.7-13 wt. %; or, the content of RH is 2.8-4 wt. %.

12. The neodymium-iron-boron magnetic material according to claim 1, wherein N is distributed at the grain boundary; or, Co is distributed in a grain boundary triangular region; or, in the grain boundary triangular region of the neodymium-iron-boron magnetic material, the distribution of Tb does not overlap the distribution of Co.

13. The neodymium-iron-boron magnetic material according to claim 1, wherein Tb is distributed at the grain boundary and the central portion of grains in the neodymium-iron-boron magnetic material; the content of Tb distributed at the grain boundary is higher than the content of Tb distributed in the central portion of the grains.

14. The neodymium-iron-boron magnetic material according to claim 1, wherein R includes a light rare earth element, the light rare earth element is Nd; the content of RH is 2.8-4 wt. %; N is distributed at the grain boundary; Co is distributed in a grain boundary triangular region; in the grain boundary triangular region of the neodymium-iron-boron magnetic material, the distribution of Tb does not overlap the distribution of Co.

15. The neodymium-iron-boron magnetic material according to claim 1, wherein R includes a light rare earth element, the light rare earth element is Nd and Pr; the content of RH is 2.8-4 wt. %; N is distributed at the grain boundary; Co is distributed in a grain boundary triangular region; in the grain boundary triangular region of the neodymium-iron-boron magnetic material, the distribution of Tb does not overlap the distribution of Co.

16. The neodymium-iron-boron magnetic material according to claim 1, wherein the neodymium-iron-boron magnetic material comprises, by mass percentage, the following components: 27-28 wt. % of Nd, 2.8-4 wt. % of Tb, 0.05-0.16 wt. % of Cu, 1.48-2.7 wt. % of Co, 0.2-0.26 wt. % of Ga, 0.25-0.3 wt. % of N, 0.46-0.5 wt. % or 0.02-0.04 wt. % of Al, 0.98-0.99 wt. % of B, 64-66 wt. % of Fe, and 0.01-0.035 wt. % of Mn, with the percentage referring to the mass percentage relative to the neodymium-iron-boron magnetic material; N is selected from the group consisting of Zr and Ti; Tb accounts for 9.7-13 wt. % of the total mass of Nd and Tb, and the mass ratio of Tb to Co is (1-15):1.

17. The neodymium-iron-boron magnetic material according to claim 1, wherein the neodymium-iron-boron magnetic material comprises, by mass percentage, the following components: 27-28 wt. % of Nd, 2.9-3.4 wt. % of Tb, 0.05-0.16 wt. % of Cu, 1.48-2.7 wt. % of Co, 0.2-0.26 wt. % of Ga, 0.26-0.3 wt. % of N, 0.46-0.5 wt. % or 0.02-0.04 wt. % of Al, 0.98-0.99 wt. % of B, and 64-66 wt. % of Fe, with the percentage referring to the mass percentage relative to the neodymium-iron-boron magnetic material; N is selected from the group consisting of Zr and Ti; Tb accounts for 9.7-11 wt. % of the total mass of Nd and Tb, the mass ratio of Tb to Co is (1-3):1.

18. The neodymium-iron-boron magnetic material according to claim 1, wherein the neodymium-iron-boron magnetic material comprises, by mass percentage, the following components: 27-28 wt. % of Nd, 2.9-3.4 wt. % of Tb, 0.05-0.16 wt. % of Cu, 1.48-2.7 wt. % of Co, 0.2-0.26 wt. % of Ga, 0.26-0.3 wt. % of N, 0.46-0.5 wt. % or 0.02-0.04 wt. % of Al, 0.98-0.99 wt. % of B, 64-66 wt. % of Fe, and 0.01-0.035 wt. % of Mn, with the percentage referring to the mass percentage relative to the neodymium-iron-boron magnetic material; N is selected from the group consisting of Zr and Ti; Tb accounts for 9.7-11 wt. % of the total mass of Nd and Tb, and the mass ratio of Tb to Co is (1-3):1.

19. The auxiliary alloy for preparing a neodymium-iron-boron magnetic material according to claim 7, wherein the composition of the auxiliary alloy is Nd.sub.i—Fe.sub.j—B.sub.k—Tb.sub.i—Co.sub.m—Cu.sub.n—Ga.sub.o—Al.sub.r—Mn.sub.t—N.sub.p, wherein i, j, k, l, m, n, o, p, r and t refer to the mass fraction of each element in the auxiliary alloy, i is 19-21 wt. %, j is 59-61 wt. %, k is 0.98-0.99 wt. %, 1 is 15-20 wt. %, m is 1.45-2.6 wt. %, n is 0.05-0.16 wt. %, o is 0.2-0.26 wt. %, r is 0.01-0.04 wt. % or 0.46-0.47 wt. %, t is 0-0.04 wt. %, and p is 0.26-0.3 wt. %.

20. The method for preparing a neodymium-iron-boron magnetic material according to claim 8, wherein the preparation process of the dual alloy method involves uniformly mixing the primary alloy and the auxiliary alloy to obtain a mixed alloy powder, and subjecting the mixed alloy powder successively to sintering and aging.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0107] FIG. 1 is the element distribution in the microstructure of the neodymium-iron-boron magnetic material in Example 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0108] The present disclosure is further described below by way of examples; however, the present disclosure is not limited to the scope of the described examples. For the experimental methods in which no specific conditions are specified in the following examples, selections are made according to conventional methods and conditions or according to the product instructions.

Example 1

[0109] 1. The raw materials for preparing a neodymium-iron-boron magnetic material in this example were a primary alloy of Nd.sub.28.46Fe.sub.66.73B.sub.0.99Tb.sub.1.2Co.sub.1.49Cu.sub.0.15Ga.sub.0.25Zr.sub.0.27Al.sub.0.46, and an auxiliary alloy of Nd.sub.20Fe.sub.60.36B.sub.0.99Tb.sub.16Co.sub.1.49Cu.sub.0.15Ga.sub.0.25Zr.sub.0.3Al.sub.0.46, wherein the numerical value of the subscript was the mass percentage of each element in the primary alloy or auxiliary alloy; and the mass ratio of the primary alloy to the auxiliary alloy was 88:12.

[0110] The preparation process for the primary alloy involved: (1) preparing the elements for the primary alloy as shown in Table 1 into a primary alloy solution; (2) passing the primary alloy solution through rotating rollers and cooling same to a temperature ranging from 700° C. to 900° C. to form a primary alloy casting strip with a uniform thickness; and (3) collecting the primary alloy casting strip by means of a collector and cooling same to 50° C. or less.

[0111] The preparation process for the auxiliary alloy involved: (1) preparing the elements for the auxiliary alloy as shown in Table 1 into an auxiliary alloy solution; (2) passing the auxiliary alloy solution through rotating rollers and cooling same to a temperature ranging from 700° C. to 900° C. to form an auxiliary alloy casting strip with a uniform thickness; and (3) collecting the auxiliary alloy casting strip by means of a collector and cooling same to 50° C. or less.

[0112] In the table below, wt. % referred to the mass percentage of each component, and “/” meant that the element was not added. “Br” referred to residual magnetic flux density, and “Hcj” referred to intrinsic coercivity.

TABLE-US-00001 TABLE 1 Raw materials of primary alloys and auxiliary alloys used in the examples and comparative examples and the mass ratio thereof Primary alloy: Content (wt. %) auxiliary Nd Tb Dy Al Cu Co Ca Zr Ti B Fe Mn alloy Example 1 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.37 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Example 2 Primary 28.46 1.3 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.63 / 86:14 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Example 3 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0 0.27 0.99 66.73 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0 0.27 0.99 60.39 / alloy Example 4 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.73 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Example 5 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.73 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Example 6 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.73 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Example 7 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.70 0.03 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.33 0.03 alloy Example 8 Primary 28.46 1.20 / 0.46 0.15 2.60 0.25 0.27 / 0.99 65.62 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 2.60 0.25 0.30 / 0.99 59.25 / alloy Example 9 Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.99 66.70 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Example 10 Primary 28.46 1.20 / 0.03 0.15 1.49 0.25 0.27 / 0.99 67.16 / 88:12 alloy Auxiliary 20.00 16.00 / 0.03 0.15 1.49 0.25 0.30 / 0.99 60.79 / alloy Example 11 Primary 28.46 1.20 / 0.46 0.05 1.49 0.25 0.27 / 0.99 66.83 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.05 1.49 0.25 0.30 / 0.99 60.46 / alloy Example 12 Primary 28.46 1.20 / 0.46 0.15 1.49 0.20 0.27 / 0.99 66.78 / 88:12 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.20 0.30 / 0.99 60.41 / alloy Comparative Primary 28.46 / 3.20 0.46 0.15 1.49 0.25 0.27 / 0.99 64.73 / 88:12 Example 1 alloy Auxiliary 20.00 / 16 0.46 0.15 1.49 0.25 0.30 / 0.99 60.36 / alloy Comparative Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.27 / 0.95 66.77 / 88:12 Example 2 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.30 / 0.95 60.40 / alloy Comparative Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.15 / 0.99 66.85 / 88:12 Example 3 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.15 / 0.99 60.51 / alloy Comparative Primary 28.46 1.20 / 0.25 0.15 1.49 0.25 0.27 / 0.99 66.94 / 88:12 Example 4 alloy Auxiliary 20.00 16.00 / 0.25 0.15 1.49 0.25 0.30 / 0.99 60.57 / alloy Comparative Primary 28.46 1.20 / 0.46 0.15 1.49 0.25 0.15 / 0.95 66.89 / 88:12 Example 5 alloy Auxiliary 20.00 16.00 / 0.46 0.15 1.49 0.25 0.15 / 0.95 60.55 / alloy Comparative Primary 28.46 1.20 / 0.46 0.15 0.18 0.25 0.27 / 0.99 68.04 / 88:12 Example 6 alloy Auxiliary 20.00 16.00 / 0.46 0.15 0.18 0.25 0.30 / 0.99 61.67 / alloy Note: The portion that made up to 100% was inevitable impurities.

[0113] 2. The preparation process for the neodymium-iron-boron magnetic material in this example involved: using a dual alloy method, wherein the primary alloy and auxiliary alloy shown in Table 1 were firstly mixed in proportion and then successively subjected to hydrogen decrepitation, a jet milling treatment, and mixing to obtain a mixed alloy powder, wherein the hydrogen decrepitation involved saturated hydrogen absorption at a hydrogen pressure of 0.067 MPa and dehydrogenation at 510° C.; and the mixing involved treatment in a three-dimensional mixer for 3 hours, and the particle size of the mixed alloy powder resulting from the jet milling treatment was 3.7 μm. Next, the mixed alloy powder was sintered at a temperature of 1070° C. for 5 hours, and then aged at 460° C. for 4 hours.

TABLE-US-00002 TABLE 2 Preparation process of neodymium-iron-boron magnetic materials in the examples and comparative examples Dehydrogenation Particle size Sintering temperature, ° C. of powder, μm temperature, ° C. Example 1 510 3.7 1070 Example 2 510 3.7 1085 Example 3 530 3.7 1085 Example 4 490 3.7 1085 Example 5 530 4.2 1085 Example 6 530 4.0 1060 Example 7 510 3.7 1070 Example 8 510 3.7 1070 Example 9 510 3.7 1070 Example 10 510 3.7 1070 Example 11 510 3.7 1070 Example 12 510 3.7 1070 Comparative 510 3.7 1070 Example 1 Comparative 510 3.7 1070 Example 2 Comparative 510 3.7 1070 Example 3 Comparative 510 3.7 1070 Example 4 Comparative 510 3.7 1070 Example 5 Comparative 510 3.7 1070 Example 6

[0114] Examples 2-12 and Comparative Examples 1-6 involved respectively preparing the primary alloys and auxiliary alloys from the raw materials shown in Table 1, wherein the preparation processes for the primary alloys and auxiliary alloys were the same as in Example 1.

[0115] The primary alloys and auxiliary alloys in Examples 2-12 and Comparative Examples 1-6 were prepared into neodymium-iron-boron magnetic materials by means of the preparation processes shown in Table 2, and the parameters not involved in Table 2 were the same as those in Example 1.

[0116] 3. The components in the finally obtained neodymium-iron-boron magnetic materials were as shown in Table 3 below.

TABLE-US-00003 TABLE 3 Mass percentage contents of the components of the magnetic materials in the examples and comparative examples Content (wt. %) Nd Tb Dy Al Cu Co Ca Zr Ti B Fe Mn Example 1 27.44 2.98 / 0.46 0.15 1.49 0.25 0.27 / 0.99 65.72 / Example 2 27.13 3.35 / 0.45 0.15 1.49 0.25 0.26 / 0.99 65.74 / Example 3 27.44 2.98 / 0.46 0.15 1.49 0.25 / 0.27 0.99 65.70 / Example 4 27.44 2.98 / 0.46 0.15 1.49 0.25 0.27 / 0.99 65.72 / Example 5 27.44 2.98 / 0.46 0.15 1.49 0.25 0.27 / 0.99 65.72 / Example 6 27.44 2.98 / 0.46 0.15 1.49 0.25 0.27 / 0.99 65.72 / Example 7 27.44 2.98 / 0.46 0.15 1.49 0.25 0.27 / 0.99 65.72 0.03 Example 8 27.44 2.98 / 0.46 0.15 2.6 0.25 0.27 / 0.99 64.86 / Example 9 27.44 2.98 / 0.46 0.15 1.49 0.25 0.30 / 0.99 65.72 / Example 10 27.44 2.98 / 0.03 0.15 1.49 0.25 0.27 / 0.99 65.72 / Example 11 27.44 2.98 / 0.46 0.05 1.49 0.25 0.27 / 0.99 65.72 / Example 12 27.44 2.98 / 0.46 0.15 1.49 0.2 0.27 / 0.99 65.72 / Comparative 27.44 / 4.74 0.46 0.15 1.49 0.25 0.27 / 0.99 65.72 / Example 1 Comparative 27.44 2.98 / 0.46 0.15 1.49 0.25 0.27 / 0.95 64.2 / Example 2 Comparative 27.44 2.98 / 0.46 0.15 1.49 0.25 0.15 / 0.99 65.82 / Example 3 Comparative 27.44 2.98 / 0.25 0.15 1.49 0.25 0.27 / 0.99 64.87 / Example 4 Comparative 27.44 2.98 / 0.46 0.15 1.49 0.25 0.15 / 0.95 65.91 / Example 5 Comparative 27.44 2.98 / 0.46 0.15 0.18 0.25 0.27 / 0.99 65.72 / Example 6 Note: The portion that made up to 100% was inevitable impurities.

Effect Example 1

[0117] (1) Magnetic Performance Test

[0118] Magnetic performance evaluation: The neodymium-iron-boron magnetic material was tested for magnetic performance by NIM-10000H BH bulk rare earth permanent magnet nondestructive measurement system from The National Institute of Metrology of China. Table 4 showed the test results of magnetic performance.

TABLE-US-00004 TABLE 4 Temperature Temperature coefficient of Br coefficient of Hcj Br Kcj at 20-100° C., at 20-100° C., No. (kGs) (kOe) α (Br) %/° C. β (Hcj) %/° C. Example 1 13.48 27.5 −0.092 −0.45 Example 2 13.39 28.4 −0.092 −0.45 Example 3 13.45 27.8 −0.092 −0.45 Example 4 13.46 27 −0.092 −0.45 Example 5 13.49 26.8 −0.092 −0.46 Example 6 13.46 26.9 −0.092 −0.46 Example 7 13.48 27.9 −0.092 −0.45 Example 8 13.48 27.6 −0.092 −0.44 Example 9 13.47 27.6 −0.092 −0.45 Example 10 13.89 25.5 −0.092 −0.44 Example 11 13.48 27.3 −0.092 −0.45 Example 12 13.49 27.2 −0.092 −0.45 Comparative 12.50 26.4 −0.092 −0.46 Example 1 Comparative 13.46 26.2 −0.092 −0.48 Example 2 Comparative 13.49 26.9 −0.092 −0.48 Example 3 Comparative 13.66 26.1 −0.092 −0.49 Example 4 Comparative 13.46 26.0 −0.092 −0.48 Example 5 Comparative 13.49 26.4 −0.092 −0.47 Example 6

[0119] (2) Test methods for the content and distribution of each element in neodymium-iron-boron magnetic materials

[0120] FE-EPMA detection: A vertical alignment plane of the neodymium-iron-boron magnetic material was polished, and tested by means of a field emission-electron probe micro-analyser (FE-EPMA) (JEOL, 8530F). Firstly, the distributions of the elements such as Tb and Co in the magnet were determined by FE-EPMA surface scanning, and then the contents of the elements such as Tb and Co in the key phases were determined by FE-EPMA single-point quantitative analysis. The test conditions were an accelerating voltage of 15 kV and a probe beam current of 50 nA.

[0121] According to FIG. 1, it can be seen that the microstructure of the neodymium-iron-boron magnetic material of Example 7 has the following characteristics: (1) according to the distribution law of the Tb-rich phase (as marked by a in the FIGURE), it is speculated that the outer layer of the main phase has a Tb-rich shell layer; (2) Zr or the other high melting point elements are enriched at the grain boundary, as shown by the mark b in the FIGURE; and (3) Co is enriched in the grain boundary triangular region, so does Tb; however, the enrichment regions of the two do not overlap, wherein the Co-enriched region is marked as c-Co, and the Tb-enriched region is marked as c-Tb.