HEAVY RARE EARTH ALLOY, NEODYMIUM-IRON-BORON PERMANENT MAGNET MATERIAL RAW MATERIAL, AND PREPARATION METHOD

Abstract

Disclosed in the present invention are a heavy rare earth alloy, neodymium-iron-boron permanent magnet material, a raw material, and a preparation method. The heavy rare earth alloy comprises the following components: RH: 30-100 mas %, not including 100 mas %; X, 0-20 mas %, not including 0; B: 0-1.1 mas %; and Fe and/or Co: 15-69 mas %, RH comprising one or more heavy rare earth elements in Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Sc, and X being Ti and/or Zr. When the heavy rare earth alloy of the present invention is used as a sub-alloy to prepare the neodymium-iron-boron permanent magnet material, a high utilization rate of heavy rare earth is achieved, so that the coercivity can also be greatly improved while the neodymium-iron-boron permanent magnet material maintains high remanence.

Claims

1. A heavy rare earth alloy comprising the following components by mass percentage: RH: 30-100 mas %, exclusive of 100 mas %; X, 0-20 mas %, exclusive of 0; B: 0-1.1 mas %; and Fe and/or Co: 15-69 mas %, wherein the sum of each component is 100 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; RH comprises one or more heavy rare earth elements selected from the group consisting of Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Sc; and X is Ti and/or Zr.

2. The heavy rare earth alloy according to claim 1, wherein, the content range of RH is 30-90 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; or, the type of RH comprises one or more heavy rare earth elements selected from the group consisting of Tb, Dy, Ho and Gd; or, the content range of X is 3-15 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; or, the content range of B is 0-0.9 mas %.

3. The heavy rare earth alloy according to claim 2, wherein, when RH comprises Tb, the content range of Tb is 30-75 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Dy, the content range of Dy is 3-75 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Ho, the content range of Ho is 2-50 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Gd, the content range of Gd is 2-50 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Tb and Dy, the content range of “Tb and Dy” is 30-90 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Tb and Ho, the content range of “Tb and Ho” is 30-90 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Tb and Gd, the content range of “Tb and Gd” is 30-90 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Tb, Dy and Gd, the content range of “Tb, Dy and Gd” is 30-90 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when RH comprises Tb, Dy, Ho and Gd, the content range of “Tb, Dy, Ho and Gd” is 30-90 mas %, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy.

4. The heavy rare earth alloy according to claim 1, wherein, when X comprises Ti, the content range of Ti is 3-15%, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when X comprises Zr, the content range of Zr is 3-10%, wherein mas % refers to the mass percentage relative to the heavy rare earth alloy; when X comprises a mixture of Zr and Ti, the mass ratio of Zr to Ti is 1:99-99:1.

5. The heavy rare earth alloy according to claim 1, comprising the following components by mass percentage: Dy: 69-75 mas %, Zr: 6.5-7.5 mas %, B: 0-0.6 mas %, the balance is Fe and/or Co; or, the heavy rare earth alloy comprises the following components by mass percentage: Dy: 69-75 mas %, Ti: 6.5-7.5 mas %, B: 0-0.6 mas %, the balance is Fe and/or Co.

6. An application of the heavy rare earth alloy according to claim 1 as a sub-alloy for preparing a neodymium-iron-boron permanent magnet material by a double alloy method.

7. A raw material of neodymium-iron-boron permanent magnet material, comprising a main alloy and a sub-alloy; the sub-alloy is the heavy rare earth alloy according to claim 1; the main alloy comprises the following components by mass percentage: R: 28.5-33.5 mas %; M: 0-5 mas %; B, 0.85-1.1 mas %, Fe: 60-70 mas %; the sum of each component is 100 mas %, wherein mas % refers to the mass percentage relative to the main alloy; R is rare earth element and the R comprises Nd; M comprises one or more selected from the group consisting of Co, Cu, Al, Ga, Ti, Zr, W, Nb, V, Cr, Ni, Zn, Ge, Sn, Mo, Pb and Bi; the mass ratio of main alloy to sub-alloy is (90-100):(0-10), wherein the main alloy is exclusive of 100 mas %, and the sub-alloy is exclusive of 0 mas %, wherein mas % refers to the mass percentage relative to the total mass of the main alloy and the sub-alloy.

8. The raw material of neodymium-iron-boron permanent magnet material according to claim 7, wherein, the mass ratio of main alloy to sub-alloy is (95-99):(1-5); or, the content range of R is 29-32.5 mas %, wherein mas % refers to the mass percentage relative to the main alloy; or, the content range of Nd is 17-28.5 mas %, wherein mas % refers to the mass percentage relative to the main alloy; or, the type of R comprises one or more selected from the group consisting of Pr, Dy, Tb, Ho and Gd; or, the content range of M is 2.5-4 mas %, wherein mas % refers to the mass percentage relative to the main alloy; or, the type of M comprises one or more selected from the group consisting of Ga, Al, Cu, Co, Ti, Zr and Nb; or, the content of B is 0.9-1.05 mas %, wherein mas % refers to the mass percentage relative to the main alloy.

9. A preparation method for a neodymium-iron-boron permanent magnet material, comprising the following steps: the molten liquid of the main alloy and the sub-alloy in the raw material of the neodymium-iron-boron permanent magnet material according to claim 7 is subject to casting respectively to obtain a main alloy sheet and a sub-alloy sheet; the main alloy sheet and the sub-alloy sheet are subject to hydrogen decrepitation, and a micro-pulverized mixture thereof is subject to forming and sintering to obtain the neodymium-iron-boron permanent magnet material.

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

11. The heavy rare earth alloy according to claim 5, wherein the heavy rare earth alloy comprises the following components by mass percentage: Dy: 75 mas %, Zr: 7.27 mas %, B: 0.5 mas %, the balance is Fe and/or Co; or, the heavy rare earth alloy comprises the following components by mass percentage: Dy: 69 mas %, Ti: 7.5 mas %, B: 0.5 mas %, the balance is Fe and/or Co.

12. The raw material of neodymium-iron-boron permanent magnet material according to claim 8, wherein: when R comprises Pr, the content range of Pr is 0-10 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when R comprises Dy, the content range of Dy is 0.5-6 mas %, wherein mas % refers to the mass percentage relative to the main alloy; when R comprises Gd, the content range of Gd is 0.2-2 mas %, wherein mas % refers to the mass percentage relative to the main alloy; when R comprises Tb, the content range of Tb is 0-5 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when R comprises Ho, the content range of Ho is 0-5 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when R comprises Dy and Gd, the mass ratio of Dy to Gd is 1:99-99:1.

13. The raw material of neodymium-iron-boron permanent magnet material according to claim 8, wherein: when M comprises Ga, the content range of Ga is 0-1 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when M comprises Al, the content range of Al is 0-1 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when M comprises Cu, the content range of Cu is 0-1 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when M comprises Co, the content range of Co is 0-2.5 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when M comprises Ti, the content range of Ti is 0-1 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when M comprises Zr, the content range of Zr is 0-1 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy; when M comprises Nb, the content range of Nb is 0-0.5 mas %, exclusive of 0, wherein mas % refers to the mass percentage relative to the main alloy.

14. The raw material of neodymium-iron-boron permanent magnet material according to claim 8, wherein the raw material of neodymium-iron-boron permanent magnet material comprises the following components by mass percentage: the mass ratio of main alloy to sub-alloy is 97:3; in the main alloy, PrNd: 26.3 mas %, Dy: 5 mas %, Gd: 0.46 mas %, Ga: 0.26 mas %, Al: 0.25 mas %, Cu: 0.21 mas %, Co: 1.2 mas %, Zr: 0.25 mas %, Nb: 0.02 mas % and B: 0.99 mas %, the balance is Fe, wherein mas % refers to the mass percentage relative to the main alloy; in the sub-alloy: Dy: 75 mas %, Zr: 7.27 mas %, B: 0.5 mas %, the balance is Fe and/or Co.

15. The raw material of neodymium-iron-boron permanent magnet material according to claim 8, wherein the raw material of neodymium-iron-boron permanent magnet material comprises the following components by mass percentage: the mass ratio of main alloy to sub-alloy is 97:3; in the main alloy, PrNd: 26.3 mas %, Dy: 4.27 mas %, Gd: 0.5 mas %, Ga: 0.3 mas %, Al: 0.19 mas %, Cu: 0.21 mas %, Co: 1.15 mas %, Ti: 0.1 mas %, Nb: 0.02 mas % and B: 0.99 mas %, the balance is Fe, wherein mas % refers to the mass percentage relative to the main alloy; in the sub-alloy: Dy: 69 mas %, Ti: 7.5 mas %, B: 0.5 mas %, the balance is Fe and/or Co.

16. The preparation method according to claim 9, wherein the preparation method comprises the following steps: the molten liquid of the main alloy and the sub-alloy in the raw material of the neodymium-iron-boron permanent magnet material is subjected to casting respectively to obtain a main alloy sheet and a sub-alloy sheet; the mixture of the main alloy sheet and the sub-alloy sheet is subject to hydrogen decrepitation, micro-pulverization, forming and sintering to obtain the neodymium-iron-boron permanent magnet material; or, the micro-pulverization process is carried out in an atmosphere with oxidizing gas having a content of 50 ppm or less.

17. The preparation method according to claim 9, wherein the preparation method comprises the following steps: the molten liquid of the main alloy and the sub-alloy in the raw material of the neodymium-iron-boron permanent magnet material is subject to casting respectively to obtain a main alloy sheet and a sub-alloy sheet; the main alloy sheet and the sub-alloy sheet are subject to hydrogen decrepitation respectively, following by mixing the coarse powder of the main alloy sheet and the sub-alloy sheet after hydrogen decrepitation, and then the coarse powder mixed is subject to micro-pulverization, forming and sintering to obtain the neodymium iron boron permanent magnet material.

18. The preparation method according to claim 9, wherein the preparation method comprises the following steps: the molten liquid of the main alloy and the sub-alloy in the raw material of the neodymium-iron-boron permanent magnet material is subject to casting respectively to obtain a main alloy sheet and a sub-alloy sheet; the main alloy sheet and the sub-alloy sheet are subject to hydrogen decrepitation and micro-pulverization respectively, following by mixing the fine powder of the main alloy sheet and the sub-alloy sheet after micro-pulverization, and then the fine powder mixed is subject to forming and sintering to obtain the neodymium iron boron permanent magnet material.

19. The neodymium-iron-boron permanent magnet material according to claim 10, wherein the neodymium-iron-boron permanent magnet material comprises Nd.sub.2Fe.sub.14B main phase and a grain boundary phase distributed between the main phases, wherein the grain boundary phase comprises Zr—B phase and/or Ti—B phase; the proportional relationship of the Zr—B phase and/or the Ti—B phase is: “(X.sub.a—B.sub.b).sub.x-T.sub.y-M.sub.p-R.sub.z”, wherein X, M and R are set forth in claim 1 independently, T is Fe and/or Co; wherein, a<b<2a, 10 at %<x<40 at %, 10 at %<y<40 at %, 20 at %<z<80 at %, 5 at %<p<20 at %; or, the grain boundary phase further comprises an oxide of RH, and the type of RH comprises one or more heavy rare earth elements selected from the group consisting of Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Sc; or, the content of Zr and/or Ti element in the grain boundary phase is higher than the content of Zr and/or Ti element in the Nd.sub.2Fe.sub.14B main phase.

20. The neodymium-iron-boron permanent magnet material according to claim 19, wherein the range of x is 20-35 at %, wherein at % refers to the atomic percentage of each element; or, the range of y is 20-35 at %, wherein at % refers to the atomic percentage of each element; or, the range of z is 25-45 at %, wherein at % refers to the atomic percentage of each element; or, the range of p is 10-25 at %, wherein at % refers to the atomic percentage of each element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0084] FIG. 1 shows the element distribution image of Pr, O, Co, Zr, B, CP, Nd, Al, Cu, Nb, Dy, Ga and Gd formed by FE-EPMA surface scan of the magnet prepared in Example 1.

[0085] FIG. 2 shows the backscattering image of the sintered magnet FE-EPMA prepared in Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0086] The present disclosure is further described below by way of examples; however, the present disclosure is not limited to the scope of the examples described hereinafter. 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.

Examples 1-5 and Comparative Examples 1-5

[0087] (1) Casting process: according to the formulations of Examples 1-5 and Comparative Examples 1-5 shown in Table 1 and the corresponding ratio of alloy A and alloy B, corresponding composition was taken and put into the vacuum melting furnace for vacuum melting in a vacuum of 5×10.sup.−2 Pa at a temperature of 1450° C. respectively; then, the molten liquids obtained by melting were respectively cast by the thin strip continuous casting method to obtain main alloy sheets and sub-alloy sheets.

[0088] (2) Hydrogen decrepitation process: at room temperature, the mixture of main alloy sheets and sub alloy sheets in step (1) were subject to hydrogen decrepitation treatment at 550° C. for 3 hours to obtain coarsely pulverized powder.

[0089] (3) Micro-pulverization process: the coarsely pulverized powder in step (2) is subject to micro-pulverization in an atmosphere with an oxidizing gas content of 50 ppm or less in a jet mill to obtain a micro-pulverized powder with an average particle size of D50 4 μm.

[0090] (4) Forming process: the powder was pressed in a press with a magnetic field strength of 2.0 T for 15 s to form a green body, and then held for 15 s under the condition of a pressure of 260 MPa to obtain a molded body.

[0091] (5) Sintering process: the molded body was sintered at 1070° C. for 7 hours, with the sintering atmosphere vacuum or argon atmosphere to obtain neodymium-iron-boron permanent magnet material.

TABLE-US-00003 TABLE 1 The components and contents of raw material composition for neodymium-iron-boron permanent magnet material (mas %) Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative No. Example 1 Example 2 Example 3 Example 4 Example 5 Example 1 Example 2 Example 3 Example 4 Example 5 main alloy R 31.76 31.07 29  32 31.3 32.28  29  31.07 31.07 31.07 Nd / / / / 28.5 / / / / / PrNd 26.3 26.3 28  30 / 25.51  28  26.3 26.3 26.3 Dy 5 4.27 1 1 1.3 7.10 1 4.27 4.27 4.27 Gd 0.46 0.5 / 1 1.5 0.45 / 0.5 0.5 0.5 Ga 0.26 0.3   0.3 0.1 0.5 0.25   0.3 0.3 0.3 0.3 Al 0.25 0.19   0.5 0.05 0.04 0.24   0.5 0.19 0.19 0.19 Cu 0.21 0.21 / 0.1 0.2 0.20 / 0.21 0.21 0.21 Co 1.2 1.15 2 1.3 / 1.16 2 1.15 1.15 1.15 Ti / 0.1 / / 0.1 / / 0.1 0.1 0.1 Zr 0.25 / / 0.1 0.095 0.46 / / / / Nb 0.02 0.02   0.05 / / 0.02   0.05 0.02 0.02 0.02 B 0.99 0.99   1.1 1 0.95 0.98   1.1 0.99 0.99 0.99 Fe balance balance balance balance balance balance balance balance balance balance sub-alloy RH 75 69  60.2 40 62.5 /  60.2 20 25 69 Tb / /  50.2 30 34 /  50.2 / / / Dy 75 69 / 5 3 / / 20 25 69 Ho / / 10  / 2.3 / 10  / / / Gd / / / 5 23.2 / / / / / Ti / 7.5 4 6.25 10 / 4 7.5 22.5 22 Zr 7.27 / 4 2 10 / 4 / / B 0.5 0.5 / 1 0.9 / / 0.5 0.5 0.5 Fe and/or Co balance balance balance balance balance balance balance balance balance balance mass ratio main alloy:sub- 97:3 97:3 90:10 92:8 95:5 100:0 87:13 97:3 97:3 97:3 alloy “/” means that the element is exclusive.

[0092] The components and content of the neodymium-iron-boron permanent magnet material in Table 2 below are the nominal composition calculated from the data in Table 1, ignoring the loss.

TABLE-US-00004 TABLE 2 The components and content of neodymium-iron-boron permanent magnet material (mas %) Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative Example 1 Example 2 Example 3 Example 4 Example 5 Example 1 Example 2 Example 3 Example 4 Example 5 R 33.06  32.21  32.12  32.64  32.86  32.28  33.06  30.74  30.89  32.21  Nd / / / / 27.08  / / / / / PrNd 25.51  25.51  25.20  27.60  / 25.51  24.36  25.51  25.51  25.51  Dy 7.10 6.21 0.90 1.32 1.39 7.10 0.87 4.74 4.89 6.21 Tb / / 5.02 2.40 1.70 / 6.53 / / / Ho / / 1.00 / 0.12 / 1.3  / / / Gd 0.45 0.49 / 1.32 2.59 0.45 / 0.49 0.49 0.49 Ga 0.25 0.29 0.27 0.09 0.48 0.25 0.26 0.29 0.29 0.29 Al 0.24 0.18 0.45 0.05 0.04 0.24 0.44 0.18 0.18 0.18 Cu 0.20 0.20 / 0.09 0.19 0.20 / 0.20 0.20 0.20 Co 1.16 1.12 1.80 1.20 / 1.16 1.74 1.12 1.12 1.12 Ti / 0.32 0.4  0.5  0.6  / 0.52 0.32 0.77 0.76 Zr 0.46 / 0.4  0.25 0.59 0.46 0.52 / / / Nb 0.02 0.02 0.05 / / 0.02 0.04 0.02 0.02 0.02 O 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 B 0.98 0.98 0.99 1.00 0.95 0.98  0.957 0.98 0.98 0.98 Fe and/ balance balance balance balance balance balance balance balance balance balance or Co “/” means that the element is exclusive.

Effective Example

[0093] The neodymium-iron-boron permanent magnet materials prepared in Examples 1-5 and Comparative Examples 1-5 were taken to observe the crystalline phase structure of the magnets by FE-EPMA respectively.

[0094] (1) Magnetic properties evaluation: the neodymium-iron-boron permanent magnet materials were tested for magnetic properties by using the PFM14.CN ultra-high coercivity permanent magnet measurement system from The National Institute of Metrology, China.

TABLE-US-00005 TABLE 3 Properties of Neodymium-Iron-Boron Permanent Magnet Materials Br Hcj Hcb Bhmax No. (kGs) (kOe) (kOe) (MGOe) Hk/Hcj Example 1 11.82 34.85 11.59 33.09 95.73 Example 2 12.00 32.77 11.73 35.03 95.95 Example 3 11.80 40.59 11.57 33.07 95.68 Example 4 12.68 28.97 12.33 38.95 95.66 Example 5 12.11 28.74 11.89 35.75 95.78 Comparative Example 1 11.79 32.92 11.51 32.81 94.80 Comparative Example 2 11.09 44.53 10.65 29.58 93.23 Comparative Example 3 12.59 27.53 12.31 38.62 94.85 Comparative Example 4 12.45 27.11 12.23 37.92 94.50 Comparative Example 5 11.89 31.58 11.62 33.85 94.53 “(BH).sub.max” refers to the maximum magnetic energy product. “Br” refers to remanence (the retaining magnetism after removal of external magnetic field following saturation magnetization of permanent magnet materials is called remanence). “Hc” refers to coercivity: magnetic polarization coercivity Hcj (intrinsic coercivity) and magnetic induction coercivity Hcb. “Hk/Hcj” refers to squareness.

[0095] (2) FE-EPMA Test:

FIG. 1 shows the element distribution image of Pr, O, Co, Zr, B, CP, Nd, Al, Cu, Nb, Dy, Ga and Gd formed by FE-EPMA surface scan of the magnet prepared in Example 1.

TABLE-US-00006 TABLE 4 No. element Nd Pr Al O Ga Cu Co Dy Gd Nb Zr B Fe sum point 1 at % 34.6 6.4 0.0225 46.8 0.033 0 0 7.8 0 0.0849 0.0283 0.1208 4.1 100 mas % 61.3 11.1 0.007 9.2 0.028 0 0 15.5 0 0.097 0.032 0.016 2.8 100 point 2 at % 26.1 7.1 0.8921 5.3 3.28 5.87 4.96 0.72 1.76 0.3151 9.7 16.22 17.8 100 mas % 45.6 12.2 0.292 1 2.77 4.53 3.54 1.4 3.35 0.355 10.73 2.13 12.1 100 point 3 at % 44 13 0.151 3.1 0.31 0.4 0.81 1.1 0 0.0113 0.085 0.0749 37 100 mas % 60 17.4 0.038 0.47 0.21 0.24 0.45 1.6 0 0.01 0.073 0.007 19.5 100 point 4 at % 7.9 1.5 0.431 2.1 0.11 0 1.16 1.3 0.53 0.0096 0.0435 3.55 81.4 100 mas % 18 3.3 0.183 0.52 0.12 0 1.08 3.3 1.31 0.014 0.062 0.603 71.5 100

[0096] As shown in Table 4 and FIG. 2, point 3 is a conventional grain boundary phase, and point 4 is the main phase; Zr—B phase (point 2) was generated in the grain boundary, resulting in that RH can only combine with O instead of combining with B to form the oxide phase of RH (point 1), therefore, the content of heavy rare earth in point 1 is higher, while the content of B in point 2 is higher; also, since the melting point of RH oxide is high, the excessive diffusion of RH from the grain boundary to the main phase and the combination with B in the main phase are inhibited thereby, which explains the reason for the performance improvement of the neodymium-iron-boron magnet material in the present disclosure from the mechanism.