R-T-B PERMANENT MAGNET MATERIAL AND PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

An R-T-B permanent magnet material and a preparation method therefor and a use thereof. The R-T-B permanent magnet material comprises the following components: R′, which is between 29.5 wt. % and 33.0 wt. %, the R comprising R, Pr, and Nd, R being a rare earth element other than Pr and Nd, the Pr content being greater than or equal to 8.85 wt. %, the mass ratio of Nd to R being less than 0.5; N, which is greater than 0.05 wt. %, and less than or equal to 4.1 wt. %, the N being Ti, Zr, or Nb; B, which is between 0.90 wt. % and 1.2 wt. %; and Fe, which is between 62.0 wt. % and 68.0 wt. %. A sintered permanent magnet product having a high coercive force and a stable temperature coefficient is prepared by using a formulation having a high Pr content. The described formulation can maximally exert the advantage of Pr, and effectively reduce production costs.

Claims

1. An R-T-B permanent magnet material, which comprises the following components by mass percentage: R′: 29.5-33.0 wt. %, R′ comprising R and Pr, Nd; wherein: R is a rare earth element other than Pr and Nd, the content of Pr is ≥8.85 wt. %, the mass ratio of Nd to R′ is <0.5; N: ≥0.05 wt. %, and <4.1 wt. %, N being Ti, Zr or Nb; B: 0.90-1.2 wt. %; Fe: 62.0-68.0 wt. %.

2. The R-T-B permanent magnet material according to claim 1, wherein, the content of R′ is 30-33 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the content of Nd is 11-15 wt. % the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the mass ratio of Nd to R′ is ≥0.3 and <0.5; or, the content of B is 0.9-1.0 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the content of Fe is 62.3-68.0 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material.

3. The R-T-B permanent magnetic material according to claim 1, wherein, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, N: 0.1-4.01 wt. %, Cu: 0.30-0.55 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt %; the percentage refers to the mass the percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, N: 0.2-0.6 wt. %, Al: 0-0.8 wt. %, but not 0, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, N: 0.2-0.6 wt. %, Ga: 0-0.81 wt. %, but not 0, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, N: 0.2-0.6 wt. %, Cu: 0.30-0.55 wt. %, Al: 0-0.8 wt. %, but not 0, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, N: 0.25-0.35 wt. %, Cu: 0.30-0.55 wt. %, Al: 0.45-0.7 wt. %, Ga: 0.2-0.6 wt. %, Co: 0.5-3.0 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, N: 0.25-0.35 wt. %, Cr: 0-0.15 wt. %, Cu: 0.30-0.55 wt. %, Al: 0.45-0.7 wt. %, Ga: 0.2-0.6 wt. %, Co: 0.5-3.0 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material comprises the following components: R′: 29.5-33.0 wt. %, Pr≥17.00 wt. %, RH: 1.0-2.5 wt. %, N: 0.25-0.35 wt. %, Cu: 0.30-0.55 wt. %, Al: 0.45-0.7 wt. %, Ga: 0.2-0.6 wt. %, Co: 0.5-3.0 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material.

4. A raw material composition of R-T-B permanent magnet material, which comprises the following components by mass percentage: R′: 29.5-32.0 wt. %, R′ comprising R and Pr, Nd; wherein: R is a rare earth element other than Pr and Nd, the content of Pr is ≥8.85 wt. %, the mass ratio of Nd to R′ is <0.5; N: ≥0.05 wt. %, and <4.0 wt. %, N being Ti, Zr or Nb; B: 0.90-1.2 wt. %; Fe: 62.0-68.0 wt. %.

5. The raw material composition of R-T-B permanent magnet material according to claim 4, wherein, the content of R′ is 30.0-32.0 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the content of Nd is 11.00-15.00 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the mass ratio of Nd to R′ is ≥0.3 and <0.5; or, the content of B is ≥0.985 wt. %; or, the content of Fe is 62.81-67.92 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material.

6. The raw material composition of R-T-B permanent magnet material according to claim 4, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, N: 0.3-0.6 wt. %, Cu: 0.34-0.55 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, N: 0.2-0.6 wt. %, Al: 0-0.8 wt. %, but not 0, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, N: 0.3-0.4 wt. %, Ga: 0.2-0.8 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, N: 0.2-0.6 wt. %, Cu: 0.30-0.5 wt. %, Al: 0-0.8 wt. %, but not 0, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, N: 0.25-0.35 wt. %, Cu: 0.3-0.5 wt. %, Al: 0.5-0.7 wt. %, Ga: 0.2-0.6 wt. %, Co: 0.5-3.0 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, N: 0.25-0.35 wt. %, Cu: 0.3-0.5 wt. %, Al: 0.5-0.7 wt. %, Ga: 0.2-0.6 wt. %, Co: 0.5-3.0 wt. %, Cr: 0-0.15 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material comprises the following components: R′: 29.5-32.0 wt. %, Pr≥17.15 wt. %, RH: 1.0-2.5 wt. %, N: 0.25-0.35 wt. %, Cu: 0.30-0.55 wt. %, Al: 0.45-0.7 wt. %, Ga: 0.2-0.6 wt. %, Co: 0.5-3.0 wt. %, B: 0.9-1.0 wt. %, Fe: 62.0-68.0 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material.

7. A preparation method for R-T-B permanent magnet material, wherein, the preparation method comprises the following steps: the molten liquid of the raw material composition of the R-T-B permanent magnet material according to claim 4 is subjected to casting, hydrogen decrepitation, forming, sintering and aging.

8. An R-T-B permanent magnet material prepared by the preparation method according to claim 7.

9. An R-T-B permanent magnet material, wherein, the main phase crystalline particle is R″.sub.2Fe.sub.14B, the R″ comprises Pr and Nd, the mass fraction of Pr in the R″ is ≥60%; the components of the R-T-B permanent magnet material are according to claim 1.

10. A use of the R-T-B permanent magnet material according to claim 1 as electronic components.

11. The R-T-B permanent magnet material according to claim 1, wherein, the content of Pr is 17.00-20.00 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material.

12. The R-T-B permanent magnet material according to claim 1, wherein, the N is Zr, the content of Zr is 0.20-4.01 wt. %; or, the N is Ti, the content of Ti is ≥0.25 wt. %; or, the N is Nb, the content of Nb is ≥0.1 wt. %; the percentage refers to the mass percentage in the R-T-B permanent magnet material.

13. The R-T-B permanent magnet material according to claim 1, wherein, R′ further comprises R, R is a rare earth element other than Pr and Nd; the content of R is 0-1 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, R′ further comprises a heavy rare earth element RH; wherein, the kind of RH is selected from the group consisting of Dy and Tb; the content of RH is 1.0-2.5 wt. %, the percentage refers to the mass percentage of the R-T-B permanent magnet material.

14. The R-T-B permanent magnet material according to claim 1, wherein, the R-T-B permanent magnet material further comprises Cu, the content of Cu is ≥0.30 wt. %, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material further comprises Al, the content of Al is 0-0.8 wt. %, but not 0, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material further comprises Ga, the content of Ga is 0.0-0.85 wt. %, but not 0, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material further comprises Co, the content of Co is 0.0-3.0 wt. %, but not 0, the percentage refers to the mass percentage in the R-T-B permanent magnet material; or, the R-T-B permanent magnet material further comprises addition element M, and M is one or more of Ni, Zn, Ag, In, Sn, Bi, V, Cr, Hf, Ta, and W; the content of M is 0-0.15 wt. %, but not 0, the percentage refers to the mass percentage in the R-T-B permanent magnet material.

15. The R-T-B permanent magnet material according to claim 1, wherein, the content of Pr is 17.00-20.00 wt. %; N is Ti or Zr; when the N is Zr, the content of Zr is 1.49-4.01 wt. %; when the N is Ti, the content of Ti is 1.51-4.01 wt. %; the main phase crystalline particle of the R-T-B permanent magnet material is R″.sub.2Fe.sub.14B, the R″ comprises Pr and Nd, the mass fraction of Pr in the R″ is ≥60%; Zr and Ti are dispersed in the main phase and grain boundary phase of in the R-T-B permanent magnet material.

16. The raw material composition of R-T-B permanent magnet material according to claim 4, wherein, the content of Pr is 17.15-19.15 wt. %; or, the N is Zr, the content of Zr is 0.25-4.0 wt. %; or, the N is Ti, the content of Ti is ≥0.3 wt. %, or, the N is Nb, the content of Nb is 0.15-0.30 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material.

17. The raw material composition of R-T-B permanent magnet material according to claim 4, wherein, R′ further comprises R, R is a rare earth element other than Pr and Nd, the content of R is 0-1 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, R′ further comprises a heavy rare earth element RH; the kind of RH is selected from the group consisting of Dy and Tb; the content of RH is 1.0-2.5 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material further comprises Cu, the content of Cu is ≥0.34 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material further comprises Al, the content of Al is 0.042-0.7 wt. %, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material further comprises Ga, the content of Ga is 0.0-0.8 wt. %, but not 0, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material further comprises Co, the content of Co is 0.0-3.0 wt. %, but not 0, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material; or, the raw material composition of R-T-B permanent magnet material further comprises addition element M, M is one or more of Ni, Zn, Ag, In, Sn, Bi, V, Cr, Hf, Ta, and W; the content of M is 0-0.15 wt. %, but not 0, the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material.

18. The raw material composition of R-T-B permanent magnet material according to claim 4, wherein, the content of Pr is 17.15-19.15 wt. %; N is Ti or Zr; when the N is Zr, the content of Zr is 1.5-4.0 wt. %; when the N is Ti, the content of Ti is 1.5-4.0 wt. %; the percentage refers to the mass percentage in the raw material composition of R-T-B permanent magnet material.

19. The preparation method for R-T-B permanent magnet material according to claim 7, wherein, the molten liquid of the raw material composition of R-T-B permanent magnet material is prepared by the following method: melting in a high frequency vacuum induction melting furnace; the vacuum degree of the melting furnace is 5×10.sup.−2 Pa; the melting temperature is 1500° C. or less; the casting process is carried out as follows: cooling at a rate of 10.sup.2° C./s −10.sup.4° C./s in an Ar atmosphere; the hydrogen decrepitation process comprises hydrogen absorption, dehydrogenation and cooling treatment, the hydrogen absorption is carried out under the hydrogen pressure of 0.15 MPa; the sintering process is carried out as follows: preheating, sintering and cooling under vacuum condition; the temperature of the preheating is 300-600° C., the time of the preheating is 1-2 h; the temperature of the sintering is 1040-1090° C.; in the aging treatment, the temperature of the secondary aging is 500-650° C.; in the secondary aging, the temperature is increased to 500-650° C. with a heating rate of 3-5° C./min.

20. The preparation method for R-T-B permanent magnet material according to claim 7, wherein, the grain boundary diffusion treatment is further carried out after sintering and before the aging treatment; the grain boundary diffusion treatment is carried out according to the following steps, attaching a substance selected from substance containing Tb and substance containing Dy to the surface of the R-T-B permanent magnet material by evaporating, coating or sputtering, then carrying out diffusion heat treatment; the temperature of the diffusion heat treatment is 800-900° C.; the time of the diffusion heat treatment is 12-48 h.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0148] FIG. 1 is the distribution diagram of Fe, Ga, Pr, Nd and Co formed by the FE-EPMA surface scanning of the sintered magnet prepared in Embodiment 50.

[0149] FIG. 2 is the distribution diagram of Al, Cu, Zr and B formed by the FE-EPMA surface scanning of the sintered magnet prepared in Embodiment 50.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0150] The following examples further illustrate the present disclosure, but the present disclosure is not limited thereto. Below presents preferred embodiments of the present disclosure based on the drawings in order to illustrate the technical schemes of the present disclosure in detail. In the following table, wt. % refers to the percentage by mass of the component in the raw material composition of the R-T-B permanent magnet material, and “I” means that the element is not added. “Br” refers to remanence, and “Hcj” refers to intrinsic coercivity.

[0151] The formulas of R-T-B permanent magnet materials of the embodiments and comparative embodiments are shown in Table 1.

TABLE-US-00001 TABLE 1 R R Nd Pr RH RH Cu Al Ga Co N N M M B Fe No. kind content wt. % wt. % kind wt. % wt. % wt. % wt. % wt. % kind wt. % kind wt. % wt. % wt. % Embodiment 1 / / 13.85 17.15 / / / / / / Zr 0.25 / / 0.9 balance Embodiment 2 / / 13.85 17.15 / / / / / / Zr 0.3 / / 0.9 balance Embodiment 3 / / 12.85 18.15 / / / / / / Zr 0.3 / / 0.9 balance Embodiment 4 / / 11.85 19.15 / / / / / / Zr 0.3 / / 0.985 balance Embodiment 5 / / 13.85 17.15 / / / / Zr 0.4 / / 0.985 balance Embodiment 6 / / 11.85 19.15 / / / / / / Zr 1.0 / / 0.985 balance Embodiment 7 / / 11.85 19.15 / / / / / / Zr 1.5 / / 0.985 balance Embodiment 8 / / 11.85 19.15 / / / / / / Zr 2.0 / / 0.985 balance Embodiment 9 / / 12.85 18.15 / / / / / / Zr 3.0 / / 0.985 balance Embodiment 10 / / 11.85 19.15 / / / / / / Zr 4.0 / / 0.985 balance Embodiment 11 / / 13.65 17.15 / / / / / / Ti 0.3 / / 0.985 balance Embodiment 12 / / 12.65 18.15 / / / / / / Ti 0.4 / / 0.985 balance Embodiment 13 / / 11.65 19.15 / / / / / / Ti 0.5 / / 0.985 balance Embodiment 14 / / 11.65 19.15 / / / / / / Ti 1 / / 0.985 balance Embodiment 15 / / 11.65 19.15 / / / / / / Ti 1.5 / / 0.985 balance Embodiment 16 / / 11.65 19.15 / / / / / / Ti 2.0 / / 0.985 balance Embodiment 17 / / 11.65 19.15 / / / / / / Ti 3.0 / / 0.985 balance Embodiment 18 / / 11.65 19.15 / / / / / / Ti 4.0 / / 0.985 balance Embodiment 19 / / 14.35 17.15 / / / / / / Nb 0.3 / / 0.985 balance Embodiment 20 / / 13.35 18.15 / / / / / / Nb 0.15 / / 0.985 balance Embodiment 21 / / 12.35 19.15 / / / / / / Nb 0.25 / / 0.985 balance Embodiment 22 / / 13.85 17.15 / / 0.34 / / / Zr 0.3 / / 0.985 balance Embodiment 23 / / 12.65 18.15 / / 0.4 / / / Ti 0.3 / / 0.985 balance Embodiment 24 / / 13.65 17.15 / / 0.45 / / / Ti 0.4 / / 0.985 balance Embodiment 25 / / 11.65 19.15 / / 0.5 / / / Ti 0.5 / / 0.985 balance Embodiment 26 / / 12.35 19.15 / / 0.5 / / / Nb 0.3 / / 0.985 balance Embodiment 27 / / 11.65 19.15 / / / 0.042 / / Ti 0.3 / / 0.985 balance Embodiment 28 / / 11.65 19.15 / / / 0.1 / / Ti 0.5 / / 0.985 balance Embodiment 29 / / 11.65 19.15 / / / 0.2 / / Ti 0.6 / / 0.985 balance Embodiment 30 / / 12.65 18.15 / / / 0.3 / / Ti 0.35 / / 0.985 balance Embodiment 31 / / 13.65 17.15 / / / 0.4 / / Ti 0.40 / / 0.985 balance Embodiment 32 / / 13.85 17.15 / / / 0.5 / / Zr 0.3 / / 0.985 balance Embodiment 33 / / 12.65 18.15 / / / 0.6 / / Ti 0.3 / / 0.985 balance Embodiment 34 / / 12.35 19.15 / / / 0.7 / / Nb 0.3 / / 0.985 balance Embodiment 35 / / 13.85 17.15 / / / / 0.2 / Zr 0.3 / / 0.985 balance Embodiment 36 / / 13.65 17.15 / / / / 0.25 / Ti 0.3 / / 0.985 balance Embodiment 37 / / 12.65 18.15 / / / / 0.4 / Ti 0.3 / / 0.985 balance Embodiment 38 / / 11.65 19.15 / / / / 0.6 / Ti 0.35 / / 0.985 balance Embodiment 39 / / 11.65 19.15 / / / / 0.8 / Ti 0.40 / / 0.985 balance Embodiment 40 / / 12.35 19.15 / / / / 0.6 / Nb 0.3 / / 0.985 balance Embodiment 41 / / 13.85 17.15 / / / / / 0.5 Zr 0.3 / / 0.985 balance Embodiment 42 / / 12.65 18.15 / / / / / 1 Ti 0.3 / / 0.985 balance Embodiment 43 / / 12.35 19.15 / / / / / 2.5 Nb 0.3 / / 0.985 balance Embodiment 44 / / 13.65 17.15 / / 0.34 0.042 / / Ti 0.3 / / 0.985 balance Embodiment 45 / / 13.65 17.15 / / 0.38 0.1 / / Ti 0.5 / / 0.985 balance Embodiment 46 / / 13.65 17.15 / / 0.40 0.2 / / Ti 0.6 / / 0.985 balance Embodiment 47 / / 12.65 18.15 / / 0.4 0.3 / / Ti 0.35 / / 0.985 balance Embodiment 48 / / 13.65 17.15 / / 0.45 0.4 / / Ti 0.4 / / 0.985 balance Embodiment 49 / / 11.65 19.15 / / 0.5 0.5 / / Ti 0.45 / / 0.985 balance Embodiment 50 / / 13.85 17.15 / / 0.34 0.5 0.2 0.5 Zr 0.3 / / 0.985 balance Embodiment 51 / / 12.65 18.15 / / 0.4 0.6 0.4 1 Ti 0.3 / / 0.985 balance Embodiment 52 / / 12.35 19.15 / / 0.5 0.7 0.6 2.5 Nb 0.3 / / 0.985 balance Embodiment 53 / / 12.85 18.15 / / 0.4 0.6 0.4 2.5 Zr 0.3 Cr 0.05 0.985 balance Embodiment 54 / / 12.85 18.15 / / 0.4 0.6 0.4 2.5 Zr 0.3 Cr 0.12 0.985 balance Embodiment 55 / / 12.35 18.15 Dy 1.5 0.4 0.6 0.4 2.5 Nb 0.3 / / 0.99 balance Embodiment 56 / / 11.35 18.15 Dy 2.5 0.4 0.6 0.4 2.5 Nb 0.3 / / 0.99 balance Embodiment 57 / / 11.35 18.15 Tb 2 0.4 0.6 0.4 2.5 Nb 0.3 / / 0.99 balance Embodiment 58 / / 11.35 18.15 Tb 1.2 0.4 0.6 0.4 2.5 Nb 0.3 / / 0.99 balance Embodiment 59 Ce 0.3 11.35 18.15 Tb 1.2 0.4 0.6 0.4 2.5 Nb 0.3 / / 0.99 balance Comparative / / 13.85 17.15 / / / / / / Mo 2.16 / / 0.985 balance Embodiment 1 Comparative / / 13.85 17.15 / / / / / / Zr 0.02 / / 0.985 balance Embodiment 2

Embodiment 1

[0152] The preparation method for the RTB-based permanent magnet material is as follows:

[0153] (1) Melting process: according to the formula shown in Table 1, the pre-prepared raw materials were put into the crucible made of aluminum oxide, and was vacuum melted in the high frequency vacuum induction melting furnace and in a vacuum of 5×10.sup.−2 Pa at a temperature of 1500° C. or less.

[0154] (2) Casting process: Ar gas was introduced into the melting furnace after vacuum melting to make the air pressure reach 55,000 Pa, and then casting was carried out, and quenching alloy was obtained at the cooling rate of 10.sup.2° C./s to 10.sup.4° C./s.

[0155] (3) Hydrogen decrepitation process: the hydrogen decrepitation furnace with quench alloy placed therein was vacuumed at room temperature, and then hydrogen with a purity of 99.9% was introduced into the hydrogen decrepitation furnace to maintain the hydrogen pressure at 0.15 MPa; after full hydrogen absorption, the temperature was raised while vacuuming for full dehydrogenation; then cooled, and took out the powder obtained from hydrogen decrepitation.

[0156] (4) Micro-pulverization process: in nitrogen atmosphere with an oxidizing gas content of 150 ppm or less and under the condition of a pressure of 0.38 MPa in the pulverization chamber, the powder obtained from hydrogen decrepitation was pulverized by jet mill pulverization for 3 hours to obtain fine powder. Oxidizing gas refers to oxygen or moisture.

[0157] (5) Zinc stearate was added to the powder pulverized by jet mill, and the addition amount of zinc stearate was 0.12% by weight of the mixed powder, and then a V-type mixer was used to fully mix.

[0158] (6) Magnetic field forming process: using a rectangular oriented magnetic field forming machine, in an orientation magnetic field of 1.6T, under a molding pressure of 0.35 ton/cm.sup.2, the above-mentioned powder added with zinc stearate was formed into a cube with a side length of 25 mm through primary forming, and it was demagnetized in a magnetic field of 0.2T after the primary forming. In order to keep the formed body obtained after primary forming from contacting the air, it was sealed, and then secondary forming was performed under a pressure of 1.3 ton/cm.sup.2 using a secondary molding machine (isostatic pressing machine).

[0159] (7) Sintering process: each formed body was moved to the sintering furnace for sintering, sintered in the vacuum of 5×10.sup.−3 Pa and at 300° C. and 600° C. for 1 h respectively; then, it was sintered at the temperature of 1050° C. for 2 hours; Ar was then introduced to make the air pressure reach 0.1 MPa and then cooled to room temperature.

[0160] (8) Aging treatment process: the sintered body was heated from 20° C. to 630° C. at a heating rate of 3-5° C./min in the Ar of high purity; after 3 hours of heat treatment at 630° C., it was cooled to room temperature and taken out.

Embodiment 2-Embodiment 59

[0161] The raw materials were prepared according to the formulas shown in Table 1, and other process conditions were the same as those in Embodiment 1, and R-T-B series sintered magnets were obtained.

Embodiment 60

[0162] Based on the sintered body obtained in Embodiment 55, the grain boundary diffusion treatment was carried out first, and then the aging treatment was carried out. Wherein, the aging treatment process is the same as in Embodiment 1, and the grain boundary diffusion treatment process is as follows:

[0163] The sintered body was processed into the magnet with diameter of 20 mm, and the thickness of the sheet material was less than 3 mm, the direction of the thickness was the direction of magnetic field orientation, after the surface was cleaned, the raw material prepared with Dy fluoride was coated on the magnet through fully spraying respectively, after drying the coated magnet, the metal attached with Tb was sputtered on the surface of the magnet in the high purity Ar atmosphere, and diffusing heat treatment was carried out at 850° C. for 24 hours. Cooled to room temperature.

Embodiment 61

[0164] Based on the sintered body obtained in Embodiment 58, and the grain boundary diffusion treatment was carried out first, and then the aging treatment was carried out. Wherein, the aging treatment process is the same as in Embodiment 1, and the grain boundary diffusion treatment process is as follows:

[0165] The sintered body was processed into the magnet with diameter of 20 mm, and the thickness of the sheet material was less than 3 mm, the direction of the thickness was the direction of magnetic field orientation, after the surface was cleaned, the raw material prepared with Tb fluoride was coated on the magnet through fully spraying respectively, after drying the coated magnet, the metal attached with Tb was sputtered on the surface of the magnet in the high purity Ar atmosphere, and diffusing heat treatment was carried out at 850° C. for 24 hours. Cooled to room temperature.

Effect Embodiment

[0166] The magnetic properties and compositions of R-T-B permanent magnet materials prepared in Embodiments 1-61 and Comparative embodiments 1-3 were determined, and the crystal phase structure of the magnets was observed by Fe-EPMA.

[0167] (1) Evaluation of magnetic properties: The NIM-10000H BH bulk rare earth permanent magnetic nondestructive measurement system in National Institute of Metrology, China was used for magnetic properties detection of permanent magnetic materials. The test results of magnetic properties are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Absolute value of Absolute value of Absolute value of Br Hcj Hcj temperature Hcj temperature Hcj temperature No. (kGs) (kOe) coefficient at 80° C. coefficient at 150° C. coefficient at 180° C. Embodiment 1 14.03 17.62 0.685 / / Embodiment 2 14.05 17.65 0.678 / / Embodiment 3 14.01 17.88 0.675 / / Embodiment 4 13.96 18.13 0.669 / / Embodiment 5 13.86 17.72 0.681 / / Embodiment 6 13.78 18.65 0.663 / / Embodiment 7 13.64 18.99 0.660 / / Embodiment 8 13.49 19.33 0.655 / / Embodiment 9 13.23 19.75 0.651 / / Embodiment 10 12.93 20.69 0.642 / / Embodiment 11 14.08 17.67 0.683 / / Embodiment 12 14.03 17.95 0.673 / / Embodiment 13 13.95 18.21 0.667 / / Embodiment 14 13.83 18.82 0.663 Embodiment 15 13.65 19.2 0.653 Embodiment 16 13.55 19.54 0.648 Embodiment 17 13.26 20.22 0.645 Embodiment 18 12.98 20.9 0.628 Embodiment 19 13.89 17.88 0.672 / / Embodiment 20 13.91 18.03 0.671 / / Embodiment 21 13.89 18.35 0.658 / / Embodiment 22 14.03 18.47 0.656 / / Embodiment 23 14.01 18.78 0.653 / / Embodiment 24 14.03 18.56 0.654 Embodiment 25 13.98 19.10 0.646 Embodiment 26 13.84 19.58 0.640 / / Embodiment 27 14.05 18.2 0.667 / / Embodiment 28 13.88 19.01 0.649 / / Embodiment 29 13.75 19.57 0.640 / / Embodiment 30 13.75 19.23 0.635 / / Embodiment 31 13.65 19.46 0.632 / / Embodiment 32 13.51 20.13 0.619 / / Embodiment 33 13.44 20.79 0.614 / / Embodiment 34 13.15 21.85 0.608 / / Embodiment 35 14.01 19.01 0.649 / / Embodiment 36 13.99 19.41 0.632 / / Embodiment 37 13.98 20.53 0.618 / / Embodiment 38 13.98 22.29 0.583 / / Embodiment 39 13.85 23.58 0.568 / / Embodiment 40 13.74 22.45 0.581 / / Embodiment 41 14.00 17.65 0.674 / / Embodiment 42 13.98 17.82 0.673 / / Embodiment 43 13.78 18.89 0.651 / / Embodiment 44 13.92 19.2 0.638 / / Embodiment 45 13.89 19.81 0.648 / / Embodiment 46 13.75 20.42 0.621 / / Embodiment 47 13.98 20.01 0.623 / / Embodiment 48 13.59 21.12 0.595 / / Embodiment 49 13.31 22.2 0.582 / / Embodiment 50 13.51 22.29 0.583 / / Embodiment 51 13.1 24.45 / 0.489 / Embodiment 52 12.95 27.09 / 0.461 / Embodiment 53 13.29 24.73 / 0.493 / Embodiment 54 13.05 27.93 / 0.456 / Embodiment 55 12.53 28.83 / 0.451 / Embodiment 56 12.33 30.5 / / 0.431 Embodiment 57 12.45 31.8 / / 0.425 Embodiment 58 12.72 29.2 / 0.442 / Embodiment 59 12.31 26.9 / 0.512 Embodiment 60 12..40 34.85 / / 0.401 Embodiment 61 12.21 40.52 / / 0.372 Comparative 13.60 19.65 0.638 / / Embodiment 1 Comparative 14.11 16.46 0.701 / / Embodiment 2 Comparative 14.2 14.8 0.771 / / Embodiment 3

[0168] (2) Composition determination: The components were determined by high frequency inductively coupled plasma emission spectrometer (ICP-OES). The composition test results are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Ce Nd Pr RH RH Cu Al Ga Co N N M M B Fe No. wt. % wt. % wt. % kind wt. % wt. % wt. % wt. % wt. % kind wt. % kind wt. % wt. % wt. % Embodiment 1 / 13.78 17.12 / / / / / / Zr 0.24 / / 0.913 balance Embodiment 2 / 13.83 17.11 / / / / / / Zr 0.31 / / 0.912 balance Embodiment 3 / 12.84 18.14 / / / / / / Zr 0.30 / / 0.9120 balance Embodiment 4 / 11.87 19.13 / / / / / / Zr 0.32 / / 0.983 balance Embodiment 5 / 13.84 17.19 / / / / / / Zr 0.42 / / 0.987 balance Embodiment 6 / 11.84 19.148 / / / / / / Zr 0.99 / / 0.985 balance Embodiment 7 / 11.851 19.148 / / / / / / Zr 1.49 / / 0.988 balance Embodiment 8 / 11.852 19.147 / / / / / / Zr 1.99 / / 0.985 balance Embodiment 9 / 12.852 18.151 / / / / / / Zr 2.99 / / 0.985 balance Embodiment 10 / 11.854 19.152 / / / / / / Zr 4.01 / / 0.988 balance Embodiment 11 / 13.59 17.13 / / / / / / Ti 0.31 / / 0.989 balance Embodiment 12 / 12.62 18.13 / / / / / / Ti 0.42 / / 0.988 balance Embodiment 13 / 11.65 19.13 / / / / / / Ti 0.48 / / 0.987 balance Embodiment 14 / 11.64 19.14 / / / / / / Ti 1.01 / / 0.985 balance Embodiment 15 / 11.63 19.13 / / / / / / Ti 1.51 / / 0.988 balance Embodiment 16 / 11.652 19.151 / / / / / / Ti 2.01 / / 0.985 balance Embodiment 17 / 11.651 19.149 / / / / / / Ti 2.98 / / 0.985 balance Embodiment 18 / 11.648 19.148 / / / / / / Ti 4.01 / / 0.988 balance Embodiment 19 / 14.35 17.19 / / / / / / Nb 0.29 / / 0.984 balance Embodiment 20 / 13.32 18.14 / / / / / / Nb 0.13 / / 0.985 balance Embodiment 21 / 12.32 19.12 / / / / / / Nb 0.26 / / 0.989 balance Embodiment 22 / 13.83 17.19 / / 0.33 / / / Zr 0.32 / / 0.985 balance Embodiment 23 / 12.63 18.19 / / 0.41 / / / Ti 0.31 / / 0.988 balance Embodiment 24 / 13.65 17.13 / / 0.44 / / / Ti 0.4 / / 0.985 balance Embodiment 25 / 11.62 19.12 / / 0.51 / / / Ti 0.5 / / 0.985 balance Embodiment 26 / 12.32 19.09 / / 0.49 / / / Nb 0.29 / / 0.988 balance Embodiment 27 / 11.61 19.14 / / / 0.041 / / Ti 0.28 / / 0.989 balance Embodiment 28 / 11.648 19.148 / / / 0.1 / / Ti 0.5 / / 0.985 balance Embodiment 29 / 11.647 19.148 / / / 0.2 / / Ti 0.6 / / 0.985 balance Embodiment 30 / 12.66 18.14 / / / 0.31 / / Ti 0.35 / / 0.985 balance Embodiment 31 / 13.68 17.16 / / / 0.38 / / Ti 0.39 / / 0.988 balance Embodiment 32 / 13.83 17.08 / / / 0.5 / / Zr 0.31 / / 0.989 balance Embodiment 33 / 12.58 18.19 / / / 0.6 / / Ti 0.28 / / 0.985 balance Embodiment 34 / 12.29 19.15 / / / 0.7 / / Nb 0.32 / / 0.989 balance Embodiment 35 / 13.79 17.18 / / / / 0.21 / Zr 0.31 / / 0.985 balance Embodiment 36 / 13.64 17.16 / / / / 0.23 / Ti 0.28 / / 0.985 balance Embodiment 37 / 12.66 18.17 / / / / 0.41 / Ti 0.29 / / 0.988 balance Embodiment 38 / 11.64 19.14 / / / / 0.58 / Ti 0.34 / / 0.985 balance Embodiment 39 / 11.64 19.14 / / / / 0.81 / Ti 0.42 / / 0.985 balance Embodiment 40 / 12.39 19.17 / / / / 0.58 / Nb 0.31 / / 0.985 balance Embodiment 41 / 13.89 17.16 / / / / / 0.49 Zr 0.28 / / 0.989 balance Embodiment 42 / 12.66 18.16 / / / / / 0.95 Ti 0.31 / / 0.989 balance Embodiment 43 / 12.39 19.16 / / / / / 2.4 Nb 0.28 / / 0.988 balance Embodiment 44 / 13.64 17.13 / / 0.34 0.043 / 0 Ti 0.32 / / 0.985 balance Embodiment 45 / 13.648 17.147 / / 0.38 0.1 / 0 Ti 0.5 0.988 balance Embodiment 46 / 13.651 17.148 / / 0.40 0.2 / 0 Ti 0.6 0.985 balance Embodiment 47 / 12.65 18.15 / / 0.4 0.32 / 0 Ti 0.34 / / 0.988 balance Embodiment 48 / 13.67 17.14 / / 0.45 0.41 / 0 Ti 0.42 / / 0.989 balance Embodiment 49 / 11.63 19.14 / / 0.51 0.48 / 0 Ti 0.44 / / 0.984 balance Embodiment 50 / 13.84 17.14 / / 0.33 0.49 0.21 0.51 Zr 0.32 / / 0.985 balance Embodiment 51 / 12.72 18.19 / / 0.41 0.62 0.39 1.1 Ti 0.31 / / 0.989 balance Embodiment 52 / 12.39 19.16 / / 0.52 0.69 0.59 2.4 Nb 0.29 / / 0.985 balance Embodiment 53 / 12.82 18.15 / / 0.41 0.62 0.41 2.53 Zr 0.31 Cr 0.05 0.988 balance Embodiment 54 / 12.83 18.16 / / 0.39 0.59 0.42 2.45 Zr 0.28 Cr 0.12 0.985 balance Embodiment 55 / 12.36 18.14 Dy 1.53 0.37 0.61 0.41 2.4 Nb 0.32 / / 0.989 balance Embodiment 56 / 11.36 18.15 Dy 2.43 0.42 0.59 0.40 2.35 Nb 0.31 / / 0.985 balance Embodiment 57 / 11.37 18.13 Tb 1.9 0.41 0.59 0.43 2.4 Nb 0.29 / / 0.988 balance Embodiment 58 / 11.32 18.19 Tb 1.12 0.41 0.59 0.41 2.53 Nb 0.29 / / 0.987 balance Embodiment 59 0.25 11.35 18.15 Tb 1.18 0.42 0.62 0.38 2.4 Nb 0.28 / / 0.99 balance Embodiment 60 / 12.37 18.13 Dy 2.02 0.38 0.62 0.42 2.42 Nb 0.31 / / 0.988 balance Embodiment 61 / 11.39 18.17 Tb 1.58 0.41 0.58 0.42 2.51 Nb 0.28 / / 0.988 balance Comparative / 13.79 17.13 / / / / / / Mo 2.13 / / 0.989 balance Embodiment 1 Comparative / 13.83 17.11 / / / / / / Zr 0.01 / / 0.989 balance Embodiment 2 Comparative / 25.3 6.1 / / / / / / Zr 0.29 / / 0.987 balance Embodiment 3

[0169] (3) FE-EPMA inspection: the perpendicularly oriented surface of the permanent magnet material in Embodiment 50 was polished and inspected using a field emission electron probe micro-analyzer (FE-EPMA) (Japan Electronics Corporation (JEOL), 8530F). The distribution of Pr, Cu, Al, B, Fe, Co and other elements in the permanent magnet material was first determined by FE-EPMA surface scanning, and then the content of Pr, Cu, Al and other elements in the key phase was determined by FE-EPMA single-point quantitative analysis with the test conditions of acceleration voltage 15 kv and probe beam current 50 nA.

[0170] The magnetic steel prepared by the formula of Embodiment 50 was mainly analyzed for Fe, Ga, Pr, Nd, Co, Al, Cu, Zr and B elements by using a field emission electron probe microanalyzer (FE-EPMA).

[0171] 1) It can be seen from FIG. 1 that Pr is mainly distributed in the main phase, and the Pr content in the main phase of R.sub.2Fe.sub.14B is more than 60% of the total rare earth content, the grain boundary phase contains some Pr which exists in the form of α-Pr and/or Pr.sub.2O.sub.3, and the grain boundary phase also contains α-Nd and/or Nd.sub.2O.sub.3. It can be seen that the (PrNd).sub.2Fe.sub.14B formed by the addition of Pr in the main phase will slightly decrease the remanence of the magnet, which is due to the slightly lower saturation magnetization intensity of Pr.sub.2Fe.sub.14B; the Hcj of the magnet is improved, which is due to the higher anisotropy field of Pr.sub.2Fe.sub.14B than that of Nd.sub.2Fe.sub.14B. In addition, due to the characteristics of easy oxidation of rare earth, some Pr.sub.2O.sub.3 and Nd.sub.2O.sub.3 will appear at the grain boundary, and the rest are a series of rare earths, all the phases at the grain boundary are nonmagnetic, so the demagnetization coupling between the main phase and the main phase is effectively isolated, which helps to improve the Hcj of the magnet.

[0172] 2) As can be seen from FIG. 1 and FIG. 2, Al (80%-95%) is distributed in the main phase, which tends to decrease the remanence while increasing the coercivity, in addition, Al is distributed at the grain boundary. Cu (55%-68%) is distributed in the main phase, according to the analysis of EPMA results, there is obvious Cu element in the grain boundary and in the intergranular triangle. The interaction of Cu element and Al element at grain boundary increases the wettability of grain boundary and main phase, makes grain boundary smoother, repairs grain boundary defects and effectively improves coercivity. Wherein, the grain boundary refers to the boundary between two grains, and the intergranular triangle refers to the void formed by three or more grains.

[0173] 3) As can be seen from FIG. 1 and FIG. 2, Zr is dispersed in the main phase and grain boundary phase. The melting point of Pr.sub.2Fe.sub.14B is slightly lower than that of normal Nd.sub.2Fe.sub.14B, meanwhile, the temperature of the ternary eutectic point also changes and its temperature coefficient deteriorates. However, when high Pr is combined with Zr element, Zr element is dispersed everywhere, which improves the temperature resistance of magnetic steel, facilitates the densification of sintering process, and makes up for the defect of deterioration of temperature coefficient caused by Pr, it can be seen that Zr element and high Pr have synergistic effect. At the same time, the high melting point metal Zr is distributed at the grain boundary, which is beneficial to the pinning of magnetic domains in magnet steel, it is not easy to demagnetize at high temperature, which effectively improves the high temperature performance of magnet.

[0174] According to the properties of magnets with Ti and Nb in the high Pr system, the distribution of Ti and Nb in the high Pr magnets is the same/similar to that of Zr elements, which provides sintered permanent magnets with high coercivity and stable temperature coefficient by synergism with high Pr.