NEODYMIUM-IRON-BORON PERMANENT MAGNET MATERIAL, PREPARATION METHOD, AND APPLICATION

Abstract

A neodymium-iron-boron permanent magnet material, a preparation method, and an application. The neodymium permanent magnet material includes R, Al, Cu, and Co; R comprises RL and RH; RL comprises one or many light rare earth elements among Nd, La, Ce, Pr, Pm, Sm, and Eu; RH comprises one or many heavy rare earth elements among Tb, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Sc; the neodymium-iron-boron permanent magnet material satisfies the following relations: (1) B/R: 0.033-0.037; (2) AI/RH: 0.12-2.7. The neodymium-iron-boron permanent magnet material has uniquely advantageous magnetic and mechanical properties, with Br≥13.12 kGs, Hcj≥17.83 kOe, and bending strength≥409 MPa.

Claims

1. A neodymium-iron-boron permanent magnet material, wherein the neodymium-iron-boron permanent magnet material comprises R, Al, Cu and Co; R comprises RL and RH; RL comprises one or more light rare earth elements of Nd, La, Ce, Pr, Pm, Sm and Eu; RH comprises one or more heavy rare earth elements of Tb, Gd, Dy, Ho, Er, Tm, Yb, Lu and Sc; the neodymium-iron-boron permanent magnet material satisfies the following relationship:
B/R: 0.033-0.037;  (1)
Al/RH: 0.12-2.7i  (2) the neodymium-iron-boron permanent magnet material further comprises M, which comprises one or more of Nb, Zr, Ti and Hf; Nb has a range of content of 0-0.5 wt. %, Zr has a range of content of 0-0.3 wt. %, Ti has a range of content of 0-0.3 wt. %.

2. The neodymium-iron-boron permanent magnet material according to claim 1, wherein, RH/R: 0-0.11 and exclusive of 0; or, B/R has a weight ratio of 0.034-0.036 or 0.033-0.034; or, Al/RH has a weight ratio of 0.35-1.25 or 0.12-2; or, RL comprises one or more of Nd, Pr and Ce; or, RH comprises one of the following: (1) Dy; (2) Tb: (3) Dy and Tb.

3. The neodymium-iron-boron permanent magnet material according to claim 1, wherein the neodymium-iron-boron permanent magnet material comprises a NdFeB main phase and an intergranular rare earth rich phase, the intergranular rare earth rich phase comprises RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase, x is 0.4-5.0, y is 0.5-1.1, z is 45-92, m is 0.5-3.5, n is 1.5-7.

4. A neodymium-iron-boron permanent magnet material, wherein the neodymium-iron-boron permanent magnet material comprises a NdFeB main phase and an intergranular rare earth rich phase, the intergranular rare earth rich phase comprises RH.sub.x—Al.sub.y-RL.sub.z—Cu.sub.m—Co.sub.n phase, x is 0.4-5.0, y is 0.5-1.1, z is 45-92, m is 0.5-3.5, n is 1.5-7; RL and RH have features as described in claim 1.

5. The neodymium-iron-boron permanent magnet material according to claim 1, wherein the neodymium-iron-boron permanent magnet material comprises, by mass percentage: R: 28-33 wt. %; RH: 0.5-2.5 wt. %; Cu: 0.35-0.55 wt. %; Al: 0.44-0.95 wt. %; Co: 0.85-1.5 wt. %; B: 0.955-1.05 wt. %; Fe: 66-69 wt. %; R comprises RL and RH; wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material.

6. The neodymium-iron-boron permanent magnet material according to claim 5, wherein R has a range of content of 28-31 wt. % or 29-33 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; or, RH has a range of content of 0.5-1.5 wt. % or 0.9-2.5 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; or, Cu has a range of content of 0.35-0.5 wt. % or 0.4-0.55 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; or, Al has a range of content of 0.44-0.85 wt. % or 0.5-0.95 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; or, Co has a range of content of 0.85-1.3 wt. % or 0.95-1.5 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; or, B has a range of content of 0.955-1.03 wt. % or 1-1.05 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; or, M has a range of content of 0.1-0.4 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; when M comprises Nb, Nb has a content of 0.2 wt. %, 0.21 wt. %, 0.23 or 0.25 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; when M comprises Zr, Zr has a content of 0.2 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material; when M comprises Ti, Ti has a content of 0.21 wt. %, wt. % refers to the mass percentage relative to the neodymium-iron-boron permanent magnet material.

7. A preparation method for a neodymium-iron-boron permanent magnet material, comprising the following steps: subjecting a melt of a raw material composition for the neodymium-iron-boron permanent magnet material to casting, coarse crushing, pulverization, forming and sintering; the raw material composition for the neodymium-iron-boron permanent magnet material comprises R, Al, Cu and Co; the R comprise RL and RH; RL and RH have features as described in claim 1; the raw material composition for the neodymium-iron-boron permanent magnet material satisfies the following relationship:
B/R: 0.033-0.037.  (1)
Al/RH: 0.12-2.7.  (2)

8. The preparation method according to claim 7, wherein the raw material composition for the neodymium-iron-boron permanent magnet material comprises, by mass percentage: R: 28-33 wt. %; RH: 0.5-2.5 wt. %; Cu: 0.35-0.55 wt. %; Al: 0.44-0.95 wt. %; Co: 0.85-1.5 wt. %; B. 0.955-1.05 wt. %; the balance is Fe and inevitable impurities; R comprises RL and RH; wt. % refers to the mass percentage relative to the raw material composition for the neodymium-iron-boron permanent magnet material; or, the process of the casting comprises pour-casting, the pour-casting has a temperature of 1420-1460° C.; or, an alloy sheet is obtained after the casting, the alloy sheet has a thickness of 0.28-0.32 mm; or, a powder obtained after the pulverization has a particle size of 4.1-4.4 μm; or, the sintering has a temperature of 1000-1100° C.; or, the sintering is further followed by an aging treatment.

9. A neodymium-iron-boron permanent magnet material prepared by the preparation method according to claim 7.

10. A use of the neodymium-iron-boron permanent magnet material according to claim 1 as an electronic component in an electric device.

11. The preparation method according to claim 8, the pour-casting has a temperature of 1425-1455° C.; or, a powder obtained after the pulverization has a particle size of 4.1-4.3 μm; or, the sintering has a temperature of 1070° C.; or, the aging treatment has a temperature of 490-530° C.; or, the aging treatment has a time of 2.5-4 hours.

12. The preparation method according to claim 11, the pour-casting has a temperature of 1430° C.; or, the alloy sheet has a thickness of 0.3 mm; or, a powder obtained after the pulverization has a particle size of 4.2 μm; or, the aging treatment has a temperature of 500-520° C.; or, the aging treatment has a time of 3 h.

13. The preparation method according to claim 12, the aging treatment has a temperature of 510° C.

14. The neodymium-iron-boron permanent magnet material according to claim 6, wherein R has a content of 29 wt. %, 31.8 wt. %, 29.5 wt. %, 31 wt. %, 31.5 wt. % or 29.2 wt. %; or, RH has a content of 0.9 wt. %, 0.5 wt. %, 1.5 wt. % or 0.8 wt. %; or, Cu has a content of 0.35 wt. %, 0.55 wt. %, 0.4 wt. %, 0.45 wt. %, 0.5 wt. % or 0.42 wt. %; or, Al has a content of 0.44 wt. %, 0.95 wt. %, 0.5 wt. %, 0.85 wt. % or 0.7 wt. %; or, Co has a content of 0.85 wt. %, 1.5 wt. %, 0.9 wt. %, 0.95 wt. %, 1.2 wt. % or 1.3 wt. %; or, B has a content of 0.96 wt. %, 1.05 wt. %, 1 wt. %, 1.03 wt. % or 1.04 wt. %.

15. The neodymium-iron-boron permanent magnet material according to claim 6, M has a range of content of 0.15-0.25 wt. %.

16. The neodymium-iron-boron permanent magnet material according to claim 4, wherein the volume ratio of the RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase to the intergranular rare earth rich phase is 4-10%.

17. The neodymium-iron-boron permanent magnet material according to claim 4, wherein the volume ratio of the RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase to the intergranular rare earth rich phase is 4.5-6%.

18. The neodymium-iron-boron permanent magnet material according to claim 2, wherein the volume ratio of the RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase to the intergranular rare earth rich phase is 4-10%.

19. The neodymium-iron-boron permanent magnet material according to claim 18, wherein the volume ratio of the RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase to the intergranular rare earth rich phase is 4.5-6%.

20. The neodymium-iron-boron permanent magnet material according to claim 2, B/R has a weight ratio of 0.0331, 0.033, 0.0339, 0.0332, 0.033 or 0.036; or, Al/RH has a weight ratio of 0.489, 1.9, 1, 0.133, 1.06 or 0.78.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0077] FIG. 1 is the SEM spectrum of the neodymium-iron-boron permanent magnet material in Example 1, wherein, point 3 is the Nd.sub.2Fe.sub.14B main phase (gray area), point 2 is the grain boundary phase (silver-white area), and point 3 is the RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase (gray-white mass) comprised in the grain boundary phase.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0078] 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.

TABLE-US-00001 TABLE 1 Formula of raw material composition for the neodymium-iron-boron permanent magnet material and contents (wt. %) Total RL RH M Nos. R Nd PrNd Tb Dy Cu Al Co B Nb Zr Ti Fe B/R Al/RH Example 1 29 28.1 / 0.9 / 0.35 0.44 0.85 0.96 0.2 / / 68.2 0.0331 0.489 Example 2 31.8 31.3 / 0.5 / 0.55 0.95 1.5 1.05 / 0.2 / 63.95 0.033 1.9 Example 3 29.5 29 / 0.1 0.4 0.4 0.5 0.9 1 0.25 / / 67.45 0.0339 1 Example 4 31 29.5 / 1.5 / 0.45 0.52 0.95 1.03 / / 0.21 66.16 0.0332 0.133 Example 5 31.5 / 30.7 0.8 / 0.5 0.85 1.2 1.04 0.21 / / 64.7 0.033 1.06 Example 6 29.2 28.3 / 0.9 / 0.42 0.7 1.3 1.05 0.23 / / 67.1 0.036 0.78 Comparative 33.5 32.6 / 0.9 / 0.5 0.85 1.2 1.08 0.2 / / 62.67 0.0322 0.94 Example 1 Comparative 27 26.5 / / 0.5 0.5 0.85 1.2 0.93 0.25 / / 69.27 0.0344 1.7 Example 2 Comparative 31.5 31.1 / 0.4 0.42 0.4 1.3 1.02 0.2 / / 65.16 0.0323 1 Example 3 Comparative 29.1 28.9 / 0.2 0.36 0.6 0.85 1.10 0.25 / / 67.74 0.0378 3 Example 4 Note: ‘/’ refers to being free of the element.

[0079] The preparation method for the neodymium-iron-boron permanent magnet materials in Examples 1-6 and Comparative Examples 1-4 was as follows:

[0080] (1) Smelting process: according to the formula shown in Table 1, the prepared raw materials were placed in a crucible made of aluminum oxide, and vacuum smelting was carried out in a high-frequency vacuum induction smelting furnace in a vacuum of 5×10.sup.−2 Pa at a temperature of 1500° C. or lower.

[0081] (2) Casting process: the melt obtained from smelting was pour-casting at 1430° C., and casting was carried out after introducing Ar gas to make the gas pressure reach 55,000 Pa, then a quenched alloy was obtained at a cooling rate of 10.sup.2-10.sup.4° C./sec, the alloy sheet has a thickness of 0.3 mm.

[0082] (3) Hydrogen-decrepitation-based pulverization process: A hydrogen decrepitation furnace, in which the quenched alloy was placed, was evacuated at room temperature, hydrogen with a purity of 99.9% was then introduced into the hydrogen decrepitation furnace, and the hydrogen pressure was maintained at 0.085 MPa; after full hydrogen absorption, the furnace was heated up while being evacuated, and full dehydrogenation was carried out at 500° C.; after cooling, a powder pulverized by hydrogen decrepitation was taken out.

[0083] (4) Micro-pulverization process: The powder pulverized by hydrogen decrepitation was subjected to jet mill pulverization for 3 hours under the conditions of an oxidizing gas content of 100 ppm or less in a nitrogen atmosphere and a pulverization chamber pressure of 0.68 MPa to obtain a fine powder, the powder has a particle size of 4.2 μm. The oxidizing gas referred to oxygen or moisture.

[0084] (5) Lubricant was added to the powder resulting from jet mill pulverization in an amount of 0.12% relative to weight of powder after mixing, and then fully mixed by means of a V-type mixer.

[0085] (6) Magnetic field forming process: The powder described above, to which Lubricant had been added, was subjected to primary formation into a cube with a side length of 25 mm by means of a right-angle alignment magnetic field forming machine in a 1.8 T alignment magnetic field at a forming pressure of 0.35 ton/cm.sup.2, and after the primary formation, the powder was demagnetized in a 0.2 T magnetic field. The formed body resulting from primary formation was sealed so that it did not come into contact with air, and secondary formation was then carried out at a pressure of 1.3 ton/cm.sup.2 by means of a secondary formation machine (an isostatic pressing machine).

[0086] (7) Sintering process: each formed body was moved to a sintering furnace for sintering in a vacuum of 5×10.sup.−3 Pa and at a temperature of 1070° C. for 6 hours, Ar gas was then introduced to make the gas pressure reach 0.05 MPa, and the formed body was then cooled to room temperature.

[0087] (8) Aging treatment process: the sintered body was aging treated for 3 hours in high-purity Ar gas at 510° C., then cooled to room temperature, and finally taken out to obtain the neodymium-iron-boron permanent magnet material.

Effect Example

[0088] The neodymium-iron-boron permanent magnet materials prepared in Examples 1-6 and Comparative Examples 1-4 were separately taken to measure the magnetic performance and compositions thereof, and the phase compositions of the magnets thereof were observed by means of field emission electron probe microanalyzer (FE-EPMA).

[0089] (1) The compositions of the neodymium-iron-boron permanent magnet materials were measured using a high-frequency inductively coupled plasma optical emission spectrometer (ICP-OES), wherein an RH.sub.x—Al.sub.y-RL.sub.Z-Cu.sub.m—Co.sub.n phase (x is 0.4-5.0, y is 0.5-1.1, z is 45-92, m is 0.5-3.5, n is 1.5-7) was obtained according to an FE-EPMA test. Table 2 below shows the composition test results, the SEM spectrum of the neodymium-iron-boron permanent magnet materials in Example 1 is shown in FIG. 1.

TABLE-US-00002 TABLE 2 Composition of neodymium-iron-boron permanent magnet material and contents (wt. %) Total RL RH M Nos. R Nd PrNd Tb Dy Cu Al Co B Nb Zr Ti Fe B/R Al/RH Example 1 29   28.1 / 0.9 / 0.35 0.44 0.85 0.96 0.2  / / 68.2  0.0331 0.489 Example 2 31.8 31.3 / 0.5 / 0.55 0.95 1.5  1.05 / 0.2 / 63.95 0.033  1.9  Example 3 29.5 29   / 0.1 0.4 0.4  0.5  0.9  1   0.25 / / 67.45 0.0339 1    Example 4 31   29.5 / 1.5 / 0.45 0.52 0.95 1.03 / / 0.21 66.16 0.0332 0.133 Example 5 31.5 / 30.7 0.8 / 0.5  0.85 1.2  1.04 0.21 / / 64.7  0.033  1.06  Example 6 29.2 28.3 / 0.9 / 0.42 0.7  1.3  1.05 0.23 / / 67.1  0.036  0.78  Comparative 33.5 32.6 / 0.9 / 0.5  0.85 1.2  1.08 0.2  / / 62.67 0.0322 0.94  Example 1 Comparative 27   26.5 / / 0.5 0.5  0.85 1.2  0.93 0.25 / / 69.27 0.0344 1.7  Example 2 Comparative 31.5 31.1 / 0.4 / 0.42 0.4  1.3  1.02 0.2  / / 65.16 0.0323 1    Example 3 Comparative 29.1 28.9 / 0.2 / 0.36 0.6  0.85 1.10 0.25 / / 67.74 0.0378 3    Example 4 Proportion of RH.sub.x—Al.sub.y—RL.sub.z—Cu.sub.m—Co.sub.n phase in intergranular Nos. rare earth rich phase RH.sub.x—Al.sub.y—RL.sub.z—Cu.sub.m—Co.sub.n Example 1  5.8% Tb.sub.3.7—Al.sub.0.51—Nd.sub.89.5—Cu.sub.1.2—Co.sub.4.6 Example 2  5.6% Tb.sub.2.4—Al.sub.1.04—Nd.sub.90.2—Cu.sub.1.5—Co.sub.5.6 Example 3 4.50% Tb.sub.0.4Dy.sub.2.5—Al.sub.0.59—Nd.sub.89.6—Cu.sub.1.4—Co.sub.5.1 Example 4 5.40% Tb.sub.4.5—Al.sub.0.68—Nd.sub.90.4—Cu.sub.1.3—Co.sub.5.2 Example 5 5.50% Tb.sub.3.1—Al.sub.0.98—Nd.sub.67.3Pr.sub.22.7—Cu.sub.1.3—Co.sub.5.1 Example 6 5.60% Tb.sub.3.8—Al.sub.0.77—Nd.sub.89.2—Cu.sub.1.2—Co.sub.5.0 Comparative No generation / Example 1 Comparative No generation / Example 2 Comparative No generation / Example 3 Comparative No generation / Example 4
In this table, the RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase: x is 0.4-5.0, y is 0.5-1.1, z is 45-92, m is 0.5-3.5, n is 1.5-7; ‘/’ referred to being free of the element.

[0090] (2) Magnetic performance evaluation: the sintered magnet 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, and the magnetic performance test results were as shown in Table 3 below. In Table 3, “Br” referred to remanence, “Hcj” referred to intrinsic coercivity, and “BHmax” referred to maximum energy product.

TABLE-US-00003 TABLE 3 Performance of neodymium-iron-boron permanent magnet material BHmax Nos. Br(kGs) Hcj(kOe) (MGOe) Bending strength (Mpa) Example 1 14.28 19.59 49.50 412 Example 2 13.12 22.13 41.38 436 Example 3 14.11 17.83 47.80 416 Example 4 13.80 22.05 45.34 451 Example 5 13.18 24.36 41.76 423 Example 6 13.87 21.16 45.37 409 Comparative 12.74 21.85 39.41 356 Example 1 Comparative 14.35 16.32 48.11 312 Example 2 Comparative 13.75 16.60 45.44 338 Example 3 Comparative 14.03 15.47 46.86 329 Example 4

[0091] As can be seen from Table 3:

1) The neodymium-iron-boron permanent magnet material of the present disclosure has both excellent magnetic performance and mechanical performance: Br≥13.12 kGs, Hcj≥17.83 kOe, BHmax≥41.38 MGOe, bending strength 409 MPa (Example 1-6); 2) Based on the formula of the present disclosure, even if the contents of R, B and Al are adjusted, as long as B/R and Al/RH are not simultaneously within the range defined in this application, RH.sub.x—Al.sub.y-RL.sub.z-Cu.sub.m—Co.sub.n phase (x is 0.4-5.0, y is 0.5-1.1, z is 45-92, m is 0.5-3.5, n is 1.5-7) cannot be generated. Thus, the Br and Hcj cannot be both maintained at higher values, and the bending strength decreased significantly (Comparative Example 1-3); 3) Based on the formula of the present disclosure, even if the values of B/R and Al/RH are adjusted but not simultaneously within the range defined in this application, both the Hcj and bending strength of the neodymium-iron-boron permanent magnet material decreased significantly (Comparative Example 4).