HIGH-CU AND HIGH-AL NEODYMIUM IRON BORON MAGNET AND PREPARATION METHOD THEREFOR

Abstract

A high-Cu and high-Al neodymium iron boron magnet and a preparation method therefor. The high-Cu and high-Al neodymium iron boron magnet comprises: 29.5-33.5% R, over 0.985% B, over 0.50% Al, over 0.35% Cu, over 1% RH, and 0.1-0.4% high-melting-point elements N and Fe, wherein the percentages are the mass percentages of the elements in the total amount of elements, and the mass percentages of the element contents must satisfy the following relationships: (1) 1<RH<0.11R<3.54B; and (2) 0.12RH<Al. By means of combining Al, RH and high-melting-point metal elements that are added at a certain ratio, the problem in which the strength of a high-Cu magnet is insufficient is effectively solved, while the magnetic performance is the magnet material is ensured.

Claims

1. A high-Cu and high-Al neodymium iron boron magnet, which comprises: 29.5-33.5% of R, 0.985% or more of B, 0.50% or more of Al, 0.35% or more of Cu, 1% or more of RH and 0.1-0.4% of high-melting-point element N and Fe; wherein, the percentage is the mass percentage of the element in the total amount of the elements; wherein, the mass percentage of the element content must satisfy the following relationships: (1) 1<RH<0.11R<3.54B; (2) 0.12RH<Al; wherein, Cu is copper; Al is aluminum; R is selected from the group consisting of praseodymium Pr and neodymium Nd; B is boron; RH is selected from the group consisting of dysprosium Dy and terbium Tb; high-melting-point metal element N is one or more selected from the group consisting of niobium Nb, zirconium Zr, titanium Ti and hafnium Hf; Fe is iron.

2. A high-Cu and high-Al neodymium iron boron magnet, which is made from the following raw materials, the raw materials comprises: 29.5-33.5% of R, 0.985% or more of B, 0.50% or more of Al, 0.35% or more of Cu, 1% or more of RH and 0.1-0.4% of high-melting-point element N and Fe; wherein, the percentage is the mass percentage of the element in the total amount of the elements; wherein, the mass percentage of the element content must satisfy the following relationships: (1) 1<RH<0.11R<3.54B; (2) 0.12RH<Al; wherein, Cu is copper; Al is aluminum; R is selected from the group consisting of praseodymium Pr and neodymium Nd; B is boron; RH is selected from the group consisting of dysprosium Dy and terbium Tb; high-melting-point metal element N is one or more selected from the group consisting of niobium Nb, zirconium Zr, titanium Ti and hafnium Hf; Fe is iron.

3. The neodymium iron boron magnet according to claim 1, wherein, the content of R is 29.5%-30.8%; or, the content of B is 0.985%-1.100%; or, the content of Fe is the balance of 100% by mass percentage; wherein, the percentage is the mass percentage of the element in the total amount of the elements.

4. The neodymium iron boron magnet according to claim 1, wherein, the neodymium iron boron magnet further comprises Co in a mass percentage of 0.9-2 wt. %; wherein, the percentage is the mass percentage of the element in the total amount of the elements.

5. The neodymium iron boron magnet according to claim 1, wherein, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 1.7%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.8%, Dy is 1.1%, Al is 0.8%, Cu is 0.6%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 1.7%, Al is 0.6%, Cu is 0.48%, Co is 1%, Zr is 0.3%, B is 1%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Tb is 1.1%, Al is 0.6%, Cu is 0.4%, Co is 1%, Zr is 0.3%, B is 0.985%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.4%, Dy is 1.5%, Al is 1.25%, Cu is 0.39%, Co is 1%, Zr is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30%, Dy is 2.2%, Al is 0.8%, Cu is 0.42%, Co is 1%, Zr is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30%, Dy is 2.3%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 29.8%, Dy is 2.3%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 2.1%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 1.9%, Al is 0.6%, Cu is 0.41%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 2.3%, Al is 0.5%, Cu is 0.4%, Co is 1%, Nb is 0.25%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 29.5%, Dy is 1.5%, Al is 0.6%, Cu is 0.41%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements.

6. A preparation method for high-Cu and high-Al neodymium iron boron magnet according to claim 1, which comprises the following steps: the raw materials of the high-Cu and high-Al neodymium iron boron magnet is successively subjected to melting, hydrogen decrepitation, jet milling, forming, sintering and aging.

7. The preparation method according to claim 6, wherein, the melting is to obtain neodymium iron boron alloy casting strips by using strip casting method; the hydrogen decrepitation comprises a hydrogen adsorption process and a dehydrogenation process, to obtain neodymium iron boron powder; wherein, the hydrogen pressure of the hydrogen adsorption process is 0.067-0.098 MPa; wherein, the temperature of the dehydrogenation process is 480-530° C.; the jet milling is to send the neodymium iron boron powder into a jet mill for jet milling to continue pulverizing to obtain fine powder; wherein, the oxygen content in the milling chamber of the jet mill in the jet milling is 50 ppm or less; wherein, the rotation speed of the sorting wheel in the jet milling is 3500-4300rpm/min; the forming is carried out under the magnetic field intensity of 1.8T or more and the protection of nitrogen atmosphere; the time of the sintering is 4-7 hours; the temperature of aging treatment is 460-520° C; the time of aging treatment is 4-10 h.

8. The preparation method according to claim 7, wherein, the average thickness of the neodymium iron boron alloy casting strips is 0.25-0.35 mm; or, the particle size of the fine powder is 3.8-4.1 μm; or, the temperature of the sintering is 1030-1080° C.

9. A high-Cu and high-Al neodymium iron boron magnet, which comprises: main phase and grain boundary phase; wherein, the composition of the main phase is: R.sub.23-29RH.sub.0.1-3.1F.sub.66-73.5Al.sub.0.45-1.53B.sub.0.9-1.1; the composition of the grain boundary phase is: R.sub.35-48RH.sub.0.5-5.9Fe.sub.46-56.5Al.sub.0.05-0.25N.sub.1.5-6.2B.sub.0.8-1.1Cu.sub.6-15; wherein, Cu is copper; Al is aluminum; R is selected from the group consisting of praseodymium Pr and neodymium Nd; B is boron; RH is selected from the group consisting of dysprosium Dy and terbium Tb; high-melting-point metal element N is one or more selected from the group consisting of niobium Nb, zirconium Zr, titanium Ti and hafnium Hf; Fe is iron; wherein, the mass ratio of the main phase to the magnet is 86-94 wt. %, and the mass ratio of the grain boundary phase to the magnet is 5-14 wt. %.

10. A use of the high-Cu and high-Al neodymium iron boron magnet according to claim 1 in a motor as motor rotor magnet material.

11. The neodymium iron boron magnet according to claim 1, wherein, the content of Al is 0.50%-1.25%, the percentage is the mass percentage of the element in the total amount of the elements.

12. The neodymium iron boron magnet according to claim 1, wherein, the content of Cu is 0.35%-0.7%, the percentage is the mass percentage of the element in the total amount of the elements.

13. The neodymium iron boron magnet according to claim 1, wherein, the content of the RH is 1.0%-2.5%, the percentage is the mass percentage of the element in the total amount of the elements.

14. The neodymium iron boron magnet according to claim 1, wherein, the content of the high-melting-point element N is 0.15%-0.35%, the percentage is the mass percentage of the element in the total amount of the elements.

15. The neodymium iron boron magnet according to claim 1, wherein, the neodymium iron boron magnet comprises main phase and grain boundary phase; wherein, the composition of the main phase is: R.sub.23-29RH.sub.0.1-3.1Fe.sub.66-73.5Al.sub.0.45-1.53B.sub.0.9-1.1; the composition of the grain boundary phase is: R.sub.35-48RH.sub.0.5-5.9Fe.sub.46-56.5Al.sub.0.05-0.25N.sub.1.5-6.2B.sub.0.8-1.1Cu.sub.6-15; wherein, the mass ratio of the main phase to the magnet is 86-94 wt. %, and the mass ratio of the grain boundary phase to the magnet is 5-14 wt. %.

16. The neodymium iron boron magnet according to claim 15, wherein, the composition of the main phase is: R.sub.23-29RH.sub.0.1-3.1Fe.sub.65-71Al.sub.0.45-1.53Co.sub.1-2.5B.sub.0.9-1.1; the composition of the grain boundary phase is: R.sub.35-48RH.sub.0.5-5.9Fe.sub.45-51Al.sub.0.05-0.25N.sub.1.5-6.2B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5; wherein, Co is cobalt.

17. The neodymium iron boron magnet according to claim 2, wherein, the content of R is 29.5%-30.8%; or, the content of B is 0.985%-1.100%; or, the content of the high-melting-point element N is 0.15%-0.35%; or, the content of Fe is the balance of 100% by mass percentage; or, the content of Al is 0.50%-1.25%; or, the content of Cu is 0.35%-0.7%; or, the content of the RH is 1.0%-2.5%; or, the raw material of the neodymium iron boron magnet further comprises Co in a mass percentage of 0.9-2 wt. %; wherein, the percentage is the mass percentage of the element in the total amount of the elements.

18. The neodymium iron boron magnet according to claim 2, wherein, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 1.7%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.8%, Dy is 1.1%, Al is 0.8%, Cu is 0.6%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 1.7%, Al is 0.6%, Cu is 0.48%, Co is 1%, Zr is 0.3%, B is 1%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Tb is 1.1%, Al is 0.6%, Cu is 0.4%, Co is 1%, Zr is 0.3%, B is 0.985%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.4%, Dy is 1.5%, Al is 1.25%, Cu is 0.39%, Co is 1%, Zr is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30%, Dy is 2.2%, Al is 0.8%, Cu is 0.42%, Co is 1%, Zr is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30%, Dy is 2.3%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 29.8%, Dy is 2.3%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 2.1%, Al is 0.6%, Cu is 0.4%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 1.9%, Al is 0.6%, Cu is 0.41%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 30.2%, Dy is 2.3%, Al is 0.5%, Cu is 0.4%, Co is 1%, Nb is 0.25%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements; or, the high-Cu and high-Al neodymium iron boron magnet comprises: the content of Nd is 29.5%, Dy is 1.5%, Al is 0.6%, Cu is 0.41%, Co is 1%, Nb is 0.2%, B is 0.99%, and Fe is the balance; wherein, the percentage is the mass percentage of the element in the total amount of the elements.

19. The neodymium iron boron magnet according to claim 9, wherein, the composition of the main phase is: R.sub.23-29RH.sub.0.1-3.1Fe.sub.65-71Al.sub.0.45-1.53Co.sub.1-2.5B.sub.0.9-1.1; the composition of the grain boundary phase is: R.sub.35-48RH.sub.0.5-5.9Fe.sub.45-51Al.sub.0.05-0.25N.sub.1.5-6.2B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5; wherein, Co is cobalt.

20. A use of the high-Cu and high-Al neodymium iron boron magnet according to claim 9 in a motor as motor rotor magnet material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0071] FIG. 1 is the SEM spectrum of the neodymium iron boron magnet of Example 1.

[0072] FIG. 2 is the EPMA spectrum of the neodymium iron boron magnet of Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0073] 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.

[0074] The mass percentages of the elements in the neodymium iron boron magnet in each Examples 1-12 and Comparative Examples 13-24 are shown in Table 1 below.

[0075] In the table below, wt. % refers to the mass percentage of the element in the total amount of the elements, and “I” means that the element is not added. “Br” is remanence, “Hcj” is the intrinsic coercivity, and “Hk/Hcj” is the squareness ratio.

[0076] Table 1 the mass percentages of the elements in neodymium iron boron magnets

TABLE-US-00001 Content (wt. %) No. Pr Nd Tb Dy Al Cu Co Nb Zr B Fe 1 / 30.2 / 1.7 0.6 0.4 1 0.2 / 0.99 bal 2 / 30.8 / 1.1 0.8 0.6 1 0.2 / 0.99 bal 3 / 30.2 / 1.7 0.6 0.48 1 / 0.3 1 bal 4 / 30.2 1.1 / 0.6 0.4 1 / 0.3 0.985 bal 5 / 30.4 / 1.5 1.25 0.39 1 / 0.2 0.99 bal 6 / 30 / 2.2 0.8 0.42 1 / 0.2 0.99 bal 7 / 30 / 2.3 0.6 0.4 1 0.2 / 0.99 bal 8 / 29.8 / 2.3 0.6 0.4 1 0.2 / 0.99 bal 9 / 30.2 / 2.1 0.6 0.4 1 0.2 / 0.99 bal 10 / 30.2 / 1.9 0.6 0.41 1 0.2 / 0.99 bal 11 / 30.2 / 2.3 0.5 0.4 1 0.25 / 0.99 bal 12 / 29.5 / 1.5 0.6 0.41 1 0.2 / 0.99 bal 13 / 30.2 / 1.7 0.4 0.4 1 0.25 / 0.99 bal 14 / 30.2 / / / 0.4 1 / / 0.99 bal 15 / 30.2 / / 0.6 0.4 1 / / 0.99 bal 16 / 30.2 / 1.7 / 0.4 1 / / 0.99 bal 17 / 30.2 / / / 0.4 1 0.2 / 0.99 bal 18 7.55 22.65 / 1.7 0.18 0.4 1 0.2 / 0.99 bal 19 / 30.2 / 0.5 0.6 0.4 1 0.2 / 0.99 bal 20 / 26 / 3 0.6 0.4 1 0.2 / 0.99 bal 21 / 32 / 1.1 0.6 0.4 1 0.2 / 0.99 bal 22 / 30.2 / 1.7 0.6 0.48 1 / 0.3 1 bal 23 7.55 22.65 / 1.7 0.6 0.48 1 / 0.3 1 bal 24 / 30.2 / 1.7 0.6 0.48 1 / 0.3 1 bal Note: bal refers to the balance.

EXAMPLE 1

[0077] The preparation method for neodymium iron boron magnet was as follows:

[0078] (1) Melting: according to the mass percentages of the elements in each example and comparative example as shown in Table 1, the raw material formulas meeting the mass percentages of the elements were configured. The raw material was melted and the strip casting method was adopted to obtain neodymium iron boron alloy casting strips.

[0079] The average thickness of the neodymium iron boron alloy casting strips was 0.28 mm

[0080] (2) Hydrogen decrepitation: the hydrogen pressure of the hydrogen adsorption process of the neodymium iron boron alloy casting strips was 0.081 MPa; the temperature of the dehydrogenation process was 500° C., neodymium iron boron powder was obtained.

[0081] (3) Jet milling: the neodymium iron boron powder was sent into a jet mill for jet milling to continue pulverizing, fine powder was obtained.

[0082] The oxygen content in the milling chamber of the jet mill was 50 ppm or less.

[0083] The rotation speed of the sorting wheel in the jet milling was 4000 rpm/min

[0084] The particle size of fine powder was 3.95 μm.

[0085] (4) Forming: the fine powder was formed by orientation under a certain magnetic field intensity to obtain the compact.

[0086] The forming was carried out under the magnetic field intensity of 1.9T and the protection of nitrogen atmosphere.

[0087] (5) Sintering

[0088] The temperature of the sintering was 1050° C. The time of the sintering was 6h.

[0089] (6) Aging

[0090] The temperature of the aging treatment was 500° C. The time of the aging treatment was 6 h.

[0091] In the preparation process of Examples 5-12 and Comparative Examples 13-17, except that the selected raw material formulas were different, the parameters in the preparation process were the same as those in Example 1.

EXAMPLE 2

[0092] The preparation method for neodymium iron boron magnet was as follows:

[0093] Except that the selected raw material formulas were different and the average thickness of the neodymium iron boron alloy casting strips in the step (1) melting was 0.30 mm, the other parameters in the preparation process were the same as those in Example 1.

[0094] For the preparation process of Comparative Examples 18-21, except that the selected raw material formulas were different, the parameters in the preparation process were the same as those in Example 2.

EXAMPLE 3

[0095] The preparation method for neodymium iron boron magnet was as follows:

[0096] Except that the selected raw material formulas were different and the temperature of the sintering in step (5) sintering was 1040° C., the other parameters in the preparation process were the same as those in Example 1.

EXAMPLE 4

[0097] The preparation method for neodymium iron boron magnet was as follows:

[0098] Except that the selected raw material formulas were different and the average thickness of the neodymium iron boron alloy casting strips in the step (1) melting was 0.29 mm, the other parameters in the preparation process were the same as those in Example 1.

COMPARATIVE EXAMPLE 22

[0099] The preparation method for neodymium iron boron magnet was as follows:

[0100] Except that the selected raw material formulas were different and the average thickness of the neodymium iron boron alloy casting strips in the step (1) melting was 0.38 mm, the other parameters in the preparation process were the same as those in Example 3.

COMPARATIVE EXAMPLE 23

[0101] The preparation method for neodymium iron boron magnet was as follows:

[0102] Except that the selected raw material formulas were different and the temperature of the sintering in step (5) sintering was 1080° C., the other parameters in the preparation process were the same as those in Example 3.

COMPARATIVE EXAMPLE 24

[0103] The preparation method for neodymium iron boron magnet was as follows:

[0104] Except that the selected raw material formulas were different and the particle size of fine powder in the step (3) jet milling was 4.25pm, the other parameters in the preparation process were the same as those in Example 3.

EFFECT EXAMPLE 1

[0105] The magnetic properties and bending strength of the neodymium iron boron magnets prepared in each example and comparative example were measured, as shown in Table 2 below.

[0106] The Br, Hcj and Hk/Hcj in each example and comparative example of the present disclosure were tested using the NIM-62000 rare earth permanent magnet measurement system of the National Institute of Metrology, China; the bending strength was tested under the standard of GB/T 14452-93 (three-point bending) using three-point bending equipment.

[0107] Table 2 the magnetic properties and bending strength of the neodymium iron boron magnets

TABLE-US-00002 Bending No. Br (kGs) Hcj (kOe) Hk/Hcj strength (MPa)  1 13.12 23.36 0.99 451  2 13.11 23.25 0.98 447  3 13.09 23.51 0.99 439  4 13.37 23.74 0.99 445  5 12.58 26.03 0.98 436  6 12.74 25.71 0.99 465  7 12.87 25.07 0.99 439  8 12.91 24.98 0.99 446  9 12.92 24.56 0.98 438 10 13.02 23.96 0.98 451 11 12.91 24.66 0.99 453 12 13.12 24.25 0.97 436 13 13.32 21.31 0.99 396 14 14.10 14.86 0.87 352 15 13.63 17.73 0.89 332 16 13.75 19.25 0.85 315 17 13.98 15.35 0.84 337 18 13.52 20.22 0.93 396 19 13.41 19.36 0.98 387 20 13.45 22.98 0.87 393 21 13.10 20.38 0.83 364 22 13.08 21.68 0.94 403 23 13.09 21.83 0.85 412 24 13.10 21.23 0.83 354

[0108] It can be seen that the examples of the present disclosure can effectively solve the problems of insufficient strength of high-Cu magnet and meanwhile ensure the magnetic properties of magnet material.

EFFECT EXAMPLE 2

[0109] By adding a certain amount of Cu, Al, Dy, Nb in combination, it can be found that Cu and high-melting-point elements such as Nb are enriched in most of the grain boundary phase area in the magnet, while the heavy rare earth elements Dy and Al are barren at grain boundaries; more specifically, Cu and high-melting-point elements such as Nb are enriched in the grain boundary phase area, and the existence of enrichment area of Cu and the high-melting-point elements in the grain boundary phase contributes to preventing the abnormal growth of crystal grains during the sintering process, reducing the sensitivity of the magnet to the temperature of the sintering, which is beneficial to increase the temperature of the sintering, the increase of the sintering temperature is beneficial to improve the coercive force and mechanical strength of the magnet. At the same time, the content of Al and Dy in the grain boundary phase is relatively low, the poorness of Al and Dy in the grain boundary phase means that more Al and Dy exist in the phase interface between the main phase and grain boundary phase of the neodymium iron boron magnet, the existence of Al in the phase interface is beneficial to improve the fluidity of the intergranular phase during the high-temperature heat treatment process, thereby forming a more stable phase interface and reducing the interface energy, thereby improving the mechanical strength of the magnet. The existence of Dy in the phase interface is beneficial to increase the magnetocrystalline anisotropy field of the phase interface, thereby increasing the coercivity of the magnet.

[0110] Taking Example 1 as an example, it can be seen from the SEM spectrum (FIG. 1) that the magnet of Example 1 is composed of main phase of Nd.sub.2Fe.sub.14B (reference number 1, gray area) and intergranular Nd-riched phase (reference number 2, silver-white area). The EPMA microanalysis of Example 1 is shown in FIG. 2.

[0111] The results of EPMA microanalysis can be obtained from FIG. 2:

[0112] The composition of the main phase of the magnet is: Nd.sub.25-28 Dy.sub.0.1-2.1Fe.sub.65-71Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1, the composition of the grain boundary phase is: Nd.sub.35-48 Dy.sub.0.5-4.5Fe.sub.45-51Al.sub.0.05-0.25Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5; wherein, the proportion of the main phase is 88-93 wt. %, and the proportion of the grain boundary phase is 7-12 wt. %.

[0113] The above is the main reason why the mechanical strength and coercivity of the magnet with high Cu content in the present disclosure do not deteriorate due to the high Cu content.

TABLE-US-00003 Grain boundary phase Main phase content No. Main phase content (%) Grain boundary phase (%)  1 Nd.sub.25-28Dy.sub.0.1-2.1Fe.sub.65-71 88-93 wt % Nd.sub.35-48Dy.sub.0.5-4.5Fe.sub.45-51Al.sub.0.05-0.25 7-12 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5  2 Nd.sub.25-28Dy.sub.0.1-1.8Fe.sub.65-71 88-94 wt % Nd.sub.35-48Dy.sub.0.5-4.1Fe.sub.45-51Al.sub.0.05-0.24 6-12 wt % Al.sub.0.77-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-14Co.sub.1-5.5  3 Nd.sub.24-28Dy.sub.0.1-2.2Fe.sub.65-71 88-93 wt % Nd.sub.35-48Dy.sub.0.5-3.9Fe.sub.45-51Al.sub.0.05-0.25 7-12 wt % Al.sub.0.77-1.2Co.sub.1-2.5B.sub.0.9-1.1 Zr.sub.1.5-6.2B.sub.0.8-1.1Cu.sub.6-14Co.sub.1-5.5  4 Nd.sub.24-28Tb.sub.1-1.8Fe.sub.65-71 89-95 wt % Nd.sub.35-48Dy.sub.0.5-4.1Fe.sub.45-51Al.sub.0.05-0.25 5-11 wt % Al.sub.0.77-1.2Co.sub.1-2.5B.sub.0.9-1.1 Zr.sub.1.5-6.2B.sub.0.8-1.1Cu.sub.6-14Co.sub.1-5.5  5 Nd.sub.23-28Dy.sub.0.1-2.1Fe.sub.65-71 87-93 wt % Nd.sub.35-48Dy.sub.0.5-4.5Fe.sub.45-51Al.sub.0.05-0.25 7-13 wt % Al.sub.0.79-1.53Co.sub.1-2.5B.sub.0.9-1.1 Zr.sub.1.5-5.6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5  6 Nd.sub.24-28Dy.sub.0.2-3.1Fe.sub.65-71 86-92 wt % Nd.sub.35-48Dy.sub.0.7-5.6Fe.sub.45-51Al.sub.0.05-0.25 8-14 wt % Al.sub.0.75-1.45Co.sub.1-2.5B.sub.0.9-1.1 Zr.sub.1.5-5.5B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5  7 Nd.sub.25-28Dy.sub.0.2-3.1Fe.sub.65-71 86-92 wt % Nd.sub.35-48Dy.sub.0.7-5.8Fe.sub.45-51Al.sub.0.05-0.21 8-14 wt % Al.sub.0.75-1.42Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-5.5B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5  8 Nd.sub.25-27Dy.sub.0.1-2.6Fe.sub.65-71 89-94 wt % Nd.sub.35-48Dy.sub.0.5-4.8Fe.sub.45-51Al.sub.0.05-0.24 6-11 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5  9 Nd.sub.25-29Dy.sub.0.1-2.0Fe.sub.65-71 88-93 wt % Nd.sub.35-48Dy.sub.0.5-4.3Fe.sub.45-51Al.sub.0.05-0.25 7-12 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 10 Nd.sub.25-29Dy.sub.0.1-1.8Fe.sub.65-71 88-94 wt % Nd.sub.35-48Dy.sub.0.5-4.1Fe.sub.45-51Al.sub.0.05-0.25 6-12 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 11 Nd.sub.25-29Dy.sub.0.2-3.1Fe.sub.65-70 86-92 wt % Nd.sub.35-48Dy.sub.0.8-5.9Fe.sub.45-51Al.sub.0.05-0.21 8-14 wt % Al.sub.0.45-0.83Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-5.8B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 12 Nd.sub.25-27Dy.sub.0.2-3.0Fe.sub.65-71 86-92 wt % Nd.sub.35-48Dy.sub.0.7-4.7Fe.sub.45-51Al.sub.0.05-0.21 8-14 wt % Al.sub.0.47-0.91Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-5.3B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 13 Nd.sub.25-28Dy.sub.0.1-2.5Fe.sub.65-71 89-94 wt % Nd.sub.35-48Dy.sub.0.5-2.5Fe.sub.45-51Al.sub.0.05-0.15 6-11 wt % Al.sub.0.32-0.67Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 14 Nd.sub.27-31Fe.sub.65-71 90-95 wt % Nd.sub.36-53Fe.sub.45-51 5-10 wt % Co.sub.1-2.5B.sub.0.9-1.1 B.sub.0.8-1.1Cu.sub.6-14Co.sub.1-5.5 15 Nd.sub.26-31Fe.sub.65-71Al.sub.0.30-0.83 88-95 wt % Nd.sub.35-48Fe.sub.45-51Al.sub.0.05-0.24 5-12 wt % Co.sub.1-2.5B.sub.0.9-1.1 B.sub.0.8-1.1Cu.sub.6-14Co.sub.1-5.5 16 Nd.sub.25-28Dy.sub.0.1-2.1Fe.sub.65-71 90-94 wt % Nd.sub.35-48Dy.sub.0.5-4.5Fe.sub.45-51 6-10 wt % Co.sub.1-2.5B.sub.0.9-1.1 B.sub.0.8-1.1Co.sub.1-5.5 17 Nd.sub.26-31Fe.sub.65-.sub.71Co.sub.1-2.5B.sub.0.9-1.1 88-93 wt % Nd.sub.38-53Fe.sub.45-51Nb.sub.1.5-6 7-12 wt % B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 18 Nd.sub.18-20Pr.sub.7-9Dy.sub.0.1-2.1Fe.sub.65-71 88-93 wt % Nd.sub.20-30Pr.sub.15-19Dy.sub.0.5-4.5Fe.sub.45-51 7-12 wt % Al.sub.0.15-0.34Co.sub.1-2.5B.sub.0.9-1.1 Al.sub.0.05-0.10Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 19 Nd.sub.25-28Dy.sub.0.1-0.6Fe.sub.65-71 89-94 wt % Nd.sub.35-48Dy.sub.0.2-0.6Fe.sub.45-51Al.sub.0.05-0.35 6-11 wt % Al.sub.0.55-1.1Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 20 Nd.sub.25-28Dy.sub.0.1-2.8Fe.sub.65-71 91-96 wt % Nd.sub.35-48Dy.sub.0.5-5.7Fe.sub.45-51Al.sub.0.05-0.25  4-9 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 21 Nd.sub.25-28Dy.sub.0.1-1.5Fe.sub.65-71 87-92 wt % Nd.sub.35-48Dy.sub.0.5-4.1Fe.sub.45-51Al.sub.0.05-0.25 8-13 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-6B.sub.0.71-0.79Cu.sub.6-15Co.sub.1-5.5 22 Nd.sub.25-29Dy.sub.0.1-2.1Fe.sub.65-72 89-94 wt % Nd.sub.35-46Dy.sub.0.5-4.5Fe.sub.45-52Al.sub.0.05-0.25 6-11 wt % Al.sub.0.55-1.1Co.sub.1-2.5B.sub.0.9-1.1 Nb.sub.1.5-.sub.6B.sub.0.8-1.1Cu.sub.6-14Co.sub.1-5.5 23 Nd.sub.18-20Pr.sub.7-9Dy.sub.0.1-2.1Fe.sub.65-71 88-94 wt % Nd.sub.20-30Pr.sub.15-19Dy.sub.0.5-4.5Fe.sub.45-51 6-12 wt % Al.sub.0.15-0.34Co.sub.1-2.5B.sub.0.9-1.1 Al.sub.0.05-.sub.0.10Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5 24 Nd.sub.25-27Dy.sub.0.1-2.1Fe.sub.65-70 88-93 wt % Nd.sub.35-49Dy.sub.0.5-4.5Fe.sub.45-52 7-12 wt % Al.sub.0.55-1.2Co.sub.1-2.5B.sub.0.9-1.1 Al.sub.0.05-0.25Nb.sub.1.5-6B.sub.0.8-1.1Cu.sub.6-15Co.sub.1-5.5