RARE EARTH PERMANENT MAGNET MATERIAL AND RAW MATERIAL COMPOSITION,PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

A rare earth permanent magnet material and a raw Material composition, a preparation method therefor and use thereof. The rare earth permanent magnet material comprises the following components in percentage by mass: 29.0-32.0 wt. % of R. where R comprises RH, and the content of RH is greater than 1 wt. %; 0.30-0.50 wt. % of Cu (not including 0.50 wt. %); 0.10-1.0 wt. % of Co; 0.05-0.20 wt. % of Ti; 0.92-0.98 wt. % of 13; and the remainder being Fe and unavoidable impurities; wherein R is a rare-earth element and at least comprises Nd; and RH is a heavy rare-earth element and at least comprises Tb. The R-T-B system permanent magnet material exhibits excellent performance, wherein Br≥14.30 kGs, and Hej≥24.1 kOe. The invention can synchronously improve Br and Hcj.

Claims

1. An R-T-B based permanent magnet material, wherein, the R-T-B based permanent magnet material comprises the following components in percentage by mass: 29.0-32.0 wt. % of R, wherein R comprises RH, and the content of RH is greater than 1 wt. %; 0.30-0.50 wt. % of Cu, not including 0.50 wt. %; 0.10-1.0 wt. % of Co; 0.05-0.20 wt. % of Ti; 0.92-0.98 wt. % of B; and the remainder being Fe and unavoidable impurities; wherein: R is a rare-earth element, and R at least comprises Nd; RH is a heavy rare-earth element, and RH at least comprises Tb.

2-10. (canceled)

11. The R-T-B based permanent magnet material according to claim 1, wherein, the content of Cu is 0.30-0.45 wt. %.

12. The R-T-B based permanent magnet material according to claim 1, wherein, the content of Ti is 0.05 wt. % or 0.10-0.20 wt. %, and wt. % refers to the mass percentage in the R-T-B based permanent magnet material.

13. The R-T-B based permanent magnet material according to claim 1, wherein, RH further comprises Dy.

14. The R-T-B based permanent magnet material according to claim 1, wherein, the content of Co is 0.10 wt. % or 0.50-1.0 wt. %, and wt. % refers to the mass percentage in the R-T-B based permanent magnet material; or, the content of B is 0.92-0.96 wt. % or 0.94-0.98 wt. %, and wt. % refers to the mass percentage in the R-T-B based permanent magnet material.

15. The R-T-B based permanent magnet material according to claim 1, wherein, the content of R is 29.5-32.0 wt. %; or, the content of RH is 1.05-1.30 wt. %.

16. The R-T-B based permanent magnet material according to claim 1, wherein, the R-T-B based permanent magnet material comprises the following components: 29.5-32.0 wt. % of R, and the content of RH is 1.05-1.3 wt. %; 30-0.45 wt. % of Cu; 0.50-1.0 wt. % of Co; 0.10-0.20 wt. % of Ti; 0.92-0.96 wt. % of B; and wt. % refers to the mass percentage in the R-T-B based permanent magnet material.

17. The R-T-B based permanent magnet material according to claim 1, wherein, the R-T-B based permanent magnet material has a high-Cu-high-Ti phase with composition ratio of (Ti.sub.1-a-b—Ti.sub.a—Cu.sub.b).sub.xR.sub.y at grain boundary of the magnet; wherein: T represents Fe and Co, 1.5b<a<2b, 70 at %<x<82 at %, 18 at %<y<30 at %, at % refers to the percentage of the atomic content of each element in the R-T-B based permanent magnet material.

18. A use of the R-T-B based permanent magnet material according to claim 1 as an electronic component in a motor.

19. A raw material composition of R-T-B based permanent magnet material, wherein, the raw material composition of R-T-B based permanent magnet material comprises the following components in percentage by mass: 31.5 wt. % of R, and R comprises RH, and the content of RH is 0.1-0.9 wt. %; 0.30-0.50 wt. % of Cu, not including 0.50 wt. %; 0.10-1.0 wt. % of Co; 0.05-0.20 wt. % of Ti; 0.92-0.98 wt. % of B; and the remainder being Fe and unavoidable impurities; wherein: R is a rare-earth element, and R at least comprises Nd; RH is a heavy rare-earth element.

20. The raw material composition of R-T-B based permanent magnet material according to claim 19, wherein, the content of R is 29.5-31.0 wt. %, and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material; or, RH comprises Tb and/or Dy; or, the content of RH is 0.5-0.9 wt. %, and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material.

21. The raw material composition of R-T-B based permanent magnet material according to claim 19, wherein, the content of Cu is 0.30-0.45 wt. %, and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material.

22. The raw material composition of R-T-B based permanent magnet material according to claim 19, wherein, the content of Ti is 0.05 wt. % or 0.10-0.20 wt. %, and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material.

23. The raw material composition of R-T-B based permanent magnet material according to claim 19, wherein, the content of Co is 0.10 wt. % or 0.50-1.0 wt. %, and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material; or, the content of B is 0.92-0.96 wt. % or 0.94-0.98 wt. %, and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material.

24. The raw material composition of R-T-B based permanent magnet material according to claim 19, wherein, the raw material composition of R-T-B based permanent magnet material comprises the following components: 29.5-31.0 wt. % of R, 0.5-0.9 wt. % of RH; 0.30-0.45 wt. % of Cu; 0.50-1.0 wt. % of Co; 0.10-0.20 wt. % of Ti; 0.92-0.96 wt. % of B; and wt. % refers to the mass percentage in the raw material composition of R-T-B based permanent magnet material.

25. A preparation method for an R-T-B based permanent magnet material, wherein, the preparation method for the R-T-B based permanent magnet material comprises the following steps: the molten liquid of the raw material composition of R-T-B based permanent magnet material according to claim 19 is subjected to casting, decrepitation, pulverization, forming, sintering, and grain boundary diffusion treatment, and the R-T-B based permanent magnet material is obtained; wherein: the heavy rare-earth elements in the grain boundary diffusion treatment comprise Tb.

26. The preparation method for the R-T-B based permanent magnet material according to claim 25, wherein, the molten liquid of the raw material composition of R-T-B based permanent magnet material is prepared as follows: melting in a high-frequency vacuum induction melting furnace; or, the process of the casting is carried out as the following steps: cooling in an Ar atmosphere at a rate of 10.sup.2° C./sec-10.sup.4° C./sec; or, the process of the decrepitation is carried out as the following steps: being subjected to hydrogen absorption, dehydrogenation and cooling treatment; or, the method of the forming is a magnetic field forming method or a hot pressing and hot deformation method; or, the process of the sintering is carried out as the following steps: preheating, sintering, and cooling under vacuum conditions; or, the grain boundary diffusion treatment is carried out as the following steps: substance containing Tb is attached to the surface of the R-T-B based permanent magnet material by evaporating, coating or sputtering, and then diffusion heat treatment is carried out; the substance containing Tb is Tb metal, a compound or an alloy containing Tb; or, after the grain boundary diffusion treatment, heat treatment is further performed.

27. The preparation method for the R-T-B based permanent magnet material according to claim 26, wherein, the vacuum degree of the melting furnace is 5×10.sup.−2Pa; and the temperature of the melting is 1500° C. or less; or, the hydrogen absorption is carried out under the condition of a hydrogen pressure of 0.15 MPa; the pulverization is a jet mill pulverization, the pressure in the pulverizing chamber of the jet mill pulverization is 0.38 MPa, and the time for the jet mill pulverization is 3 hours; or, the temperature of preheating is 300-600° C., and the time of preheating is 1-2h; the temperature of sintering is 900° C-1100° C., and the time of sintering is 2h; or, the temperature of the diffusion heat treatment is 800-900° C., and the time of the diffusion heat treatment is 12-48h; or, the temperature of the heat treatment is 450-550° C., and the time of the heat treatment is 3h.

28. An R-T-B based permanent magnet material prepared by the preparation method for the R-T-B based permanent magnet material according to claim 25.

29. A use of the R-T-B based permanent magnet material according to claim 28 as an electronic component in a motor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0121] FIG. 1 shows the distribution diagrams of Nd, Cu, and Ti elements formed by FE-EPMA surface scan of the permanent magnet material prepared in Example 7 (from left to right are the concentration distribution diagrams of Nd element, Cu element, and Ti element, and the legend indicates that different colors correspond to different concentration values), wherein point 1 is the main phase and point 2 is the high-Cu-rich-Ti phase.

[0122] FIG. 2 shows the distribution diagrams of Nd, Cu and Ti elements formed by FE-EPMA surface scan of the permanent magnet material prepared in Comparative Example 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0123] 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 embodiments are selected according to conventional methods and conditions, or according to the product specification.

[0124] In the following examples and comparative examples, the purity of Nd and Tb is 99.8%, the purity of Fe-B is industrial grade purity, the purity of pure Fe is industrial grade purity, and the purity of Co, Cu, and. Ti is 99.9%.

[0125] The formulations of the R-T-B based permanent magnet materials in the examples and the comparative examples are shown in Table 1. The wt. % in Table 1 and the later Table 3 refers to the mass percentage of each raw material in the R-T-B based permanent magnet material, and “\” indicates that the element was not added.

TABLE-US-00001 TABLE 1 Formulations for the raw material compositions of the R-T-B based permanent magnet materials (wt. %) No. Nd PrNd Tb Dy Cu Co Ti B Fe Ga Al Zr Mo W Mn Example 1 29.0 / 0.50 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 2 30.0 / 0.50 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 3 30.5 / 0.50 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 4 30.0 / 0.50 / 0.35 0.50 0.10 0.92 remainder / / / / / / Example 5 30.0 / 0.50 / 0.40 0.50 0.10 0.92 remainder / / / / / / Example 6 30.0 / 0.50 / 0.45 0.50 0.10 0.92 remainder / / / / / / Example 7 30.0 / 0.50 / 0.40 0.80 0.10 0.92 remainder / / / / / / Example 8 30.0 / 0.50 / 0.40 1.0 0.05 0.94 remainder / / / / / / Example 9 30.0 / 0.50 / 0.40 1.0 0.10 0.94 remainder / / / / / / Example 10 30.0 / 0.50 / 0.40 1.0 0.15 0.94 remainder / / / / / / Example 11 30.0 / 0.50 / 0.40 1.0 0.20 0.94 remainder / / / / / / Example 12 30.0 / 0.50 / 0.40 1.0 0.10 0.95 remainder / / / / / / Example 13 30.0 / 0.50 / 0.40 1.0 0.10 0.98 remainder / / / / / / Example 14 / 30 / 0.8 0.4 0.5 0.10 0.92 remainder / / / / / / Comparative 28.0 / 0.50 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 1 Comparative 32.0 / 0.50 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 2 Comparative 30.0 / 0.50 / 0.20 0.50 0.10 0.92 remainder / / / / / / Example 3 Comparative 30.0 / 0.50 / 0.50 0.50 0.10 0.92 remainder / / / / / / Example 4 Comparative 30.0 / 0.50 / 0.50 0.30 0.25 0.92 remainder / / / / / / Example 5 Comparative 30.0 / 0.50 / 0.40 0.30 0.05 0.89 remainder / / / / / / Example 6 Comparative 28.0 / 0.50 / 0.40 0.10 0.20 0.92 remainder 0.30 0.20 / / / / Example 7 Comparative 30.0 / 0.50 / 0.40 0.10 / 0.92 remainder / / 0.20 / / / Example 8 Comparative 30.0 / 0.50 / 0.40 0.10 / 0.92 remainder / / / 0.20 / / Example 9 Comparative 30.0 / 0.50 / 0.40 0.10 / 0.92 remainder / / / / 0.20 / Example 10 Comparative / 29.1 / 0.5 0.20 2.0 / 0.9 remainder 0.20 0.20 0.15 / / 0.03 Example 11

[0126] The R-T-B based permanent magnet materials were prepared as follows:

[0127] (1) Melting process: according to the formulations shown in Table 1, the prepared raw materials were put into a crucible made of alumina and vacuum melted in a high-frequency vacuum induction melting furnace and in a vacuum of 5×10.sup.−2 Pa at a temperature of 1500° C. or less.

[0128] (2) Casting process: after vacuum melting, the melting furnace was fed with Ar gas to make the air pressure reach 55,000 Pa and then casting was carried out, and a cooling rate of 10.sup.2° C./sec-10.sup.4° C./sec was used to obtain the quench alloy.

[0129] (3) Hydrogen decrepitation process: the furnace for hydrogen decrepitation with quench alloy placed therein was evacuated at room temperature, and then hydrogen gas of 99.9% purity was passed into the furnace for hydrogen decrepitation to maintain the hydrogen pressure at 0.15 MPa; after sufficient hydrogen absorption, it was sufficiently dehydrogenated by heating up while vacuum-pumping; then it was cooled and the powder after hydrogen decrepitation was taken out.

[0130] (4) Micro-pulverization process: the powder after hydrogen decrepitation was pulverized by jet mill for 3 hours in nitrogen atmosphere with oxidizing gas content of 1.50 ppm or less and under the condition of the pressure of 0.38 MPa in the pulverization chamber, and fine powder was obtained. The oxidizing gas refers to oxygen or moisture.

[0131] (5) Zinc stearate was added to the powder after jet mill pulverization, and the addition amount of zinc stearate was 0.12% by weight of the mixed powder, and then it was mixed thoroughly by using a V-mixer.

[0132] (6) Magnetic field forming process: a rectangular oriented magnetic field forming machine was used to conduct primary forming of the above-mentioned powder with zinc stearate into a cube with sides of 25 mm at one time in an orientation magnetic field of 1.6 T and a forming pressure of 0.35 ton/cm.sup.2; after the primary forming, it was demagnetized in a magnetic field of 0.2 T, In order to prevent the formed body after the primary forming from contacting with air, it was sealed, and then secondary forming was carried out at a pressure of 1.3 ton/cm.sup.2 using a secondary forming machine (isostatic forming machine)

[0133] (7) Sintering process: each formed body was moved to a sintering furnace for sintering, the sintering was maintained under a vacuum of 5×10.sup.−3 Pa and at a temperature of 300° C. and 600° C. for 1 hour, respectively; then, sintered at a temperature of 1040° C. for 2 hours; and then Ar gas was passed in to make the air pressure reach 0.1 MPa, and cooled to room temperature.

[0134] (8) Grain boundary diffusion treatment process: the sintered body of each group was processed into a magnet with a diameter of 20 mm and a thickness of 5 mm, and the thickness direction is the magnetic field orientation direction, after the surface was cleaned, the raw materials formulated with Tb fluoride were used to coat the magnet through a full spray, and the coated magnet was dried, and the metal with Tb elements was attached to the magnet surface by sputtering in a high-purity Ar gas atmosphere, diffusion heat treatment was carried out at a temperature of 850° C. for 24 hours. Cooled to room temperature.

[0135] (9) Heat treatment process: the sintered body was heat treated in high purity Ar gas at a temperature of 500° C. for 3 hours and then cooled to room temperature and taken out.

[0136] Effectiveness Example

[0137] The magnetic properties and compositions of the R-T-B based permanent magnet materials made in Examples 1-14 and Comparative Examples 1-11 were measured, and the crystalline phase structure of the magnets was observed using a field emission electron probe microanalyzer (FE-EPMA).

[0138] (1) Magnetic properties evaluation: The magnetic properties were examined using the NIM-1000011 type BH bulk rare earth permanent magnet nondestructive measurement system in National Institute of Metrology, China, The following Table 2 indicates the magnetic property testing results. In Table 2, “Br” is the residual magnetic flux density, “Hcj” is the intrinsic coercivity, “SQ” is the squareness ratio, and “BHmax” is the maximum energy product.

TABLE-US-00002 TABLE 2 No. Br (kGs) Hcj (kOe) SQ (%) BHmax(MGoe) Example 1 14.51 24.4 99.0 51.0 Example 2 14.42 25.1 99.6 50.3 Example 3 14.32 25.6 99.6 49.6 Example 4 14.49 24.3 99.5 50.8 Example 5 14.41 25.2 99.7 50.5 Example 6 14.33 24.1 99.8 49.6 Example 7 14.45 25.5 99.8 50.3 Example 8 14.48 24.9 99.6 50.6 Example 9 14.50 24.5 99.4 51.0 Example 10 14.49 24.5 99.5 50.7 Example 11 14.45 24.9 99.2 50.6 Example 12 14.39 25.2 99.1 50.1 Example 13 14.42 24.3 99.5 50.6 Example 14 14.30 25.7 99.5 49.7 Comparative 14.06 16.8 88.2 47.0 Example 1 Comparative 13.24 26.1 99.0 42.1 Example 2 Comparative 14.52 21.6 99.3 51.0 Example 3 Comparative 14.24 23.4 97.6 49.1 Example 4 Comparative 14.21 23.2 99.0 48.9 Example 5 Comparative 14.11 24.2 97.3 47.8 Example 6 Comparative 13.84 25.5 99.0 46.4 Example 7 Comparative 14.35 23.5 99.0 49.6 Example 8 Comparative 14.25 23.2 98.9 49.0 Example 9 Comparative 14.22 23.6 99.0 49.0 Example 10 Comparative 14.28 25.9 91.6 48.3 Example 11

[0139] From Table 2, it can be seen that:

[0140] (1) the R-T-B based permanent magnet materials of the present disclosure have excellent performance with Br≥14.30 kGs and Hcj 24.1 kOe, achieving simultaneous improvement of Br and Hcj (Examples 1-14).

[0141] (2) Based on the formulation of the present disclosure, as the amount of raw materials R, Cu, Co, Ti and B is changed, the performance of the R-T-B based permanent magnet materials decreases significantly (Comparative Examples 1-6),

[0142] (3) During the research, the inventor found that after the addition of a larger amount of Cu and high melting point Ti, part of Ti enters the grain boundary to form a high-Cu-high-Ti phase, which is beneficial to the performance of the R-T-B based permanent magnet materials; however, not all elements with similar properties can form this phase, for example the addition of Ga and Al (Comparative Example 7), and for another example the addition of high melting point metals such as Zr, Mo and W (Comparative Example 8-10), are not able to obtain the R-T-B based permanent magnet materials in the present closure,

[0143] (2) Composition determination: the components were determined using a high-frequency inductively coupled plasma emission spectrometer (1CP-OES). The following Table 3 shows the results of the composition testing.

TABLE-US-00003 TABLE 3 Composition test results (wt. %) No. Nd PrNd Tb Dy Cu Co Ti B Fe Ga Al Zr Mo W Mn Example 1 29.0 / 1.05 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 2 30.0 / 1.05 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 3 30.5 / 1.06 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 4 30.0 / 1.05 / 0.35 0.50 0.10 0.92 remainder / / / / / / Example 5 30.0 / 1.07 / 0.40 0.50 0.10 0.92 remainder / / / / / / Example 6 30.0 / 1.06 / 0.45 0.50 0.10 0.92 remainder / / / / / / Example 7 30.0 / 1.06 / 0.40 0.8 0.10 0.92 remainder / / / / / / Example 8 30.0 / 1.07 / 0.40 1.0 0.05 0.94 remainder / / / / / / Example 9 30.0 / 1.06 / 0.40 1.0 0.10 0.94 remainder / / / / / / Example 10 30.0 / 1.05 / 0.40 1.0 0.15 0.94 remainder / / / / / / Example 11 30.0 / 1.05 / 0.40 1.0 0.20 0.94 remainder / / / / / / Example 12 30.0 / 1.06 / 0.40 1.0 0.10 0.95 remainder / / / / / / Example 13 30.0 / 1.05 / 0.40 1.0 0.10 0.98 remainder / / / / / / Example 14 / 30 0.5 0.8 0.40 0.5 0.1 0.92 remainder / / / / / / Comparative 28.0 / 0.95 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 1 Comparative 32.0 / 1.06 / 0.30 0.10 0.05 0.92 remainder / / / / / / Example 2 Comparative 30.0 / 1.07 / 0.20 0.50 0.10 0.92 remainder / / / / / / Example 3 Comparative 30.0 / 1.05 / 0.50 0.50 0.10 0.92 remainder / / / / / / Example 4 Comparative 30.0 1.03 0.5 0.30 0.25 0.92 remainder / / / / / / Example 5 Comparative 30.0 / 1.06 / 0.40 0.30 0.05 0.89 remainder / / / / / / Example 6 Comparative 28 / 1.07 / 0.40 0.10 0.20 0.92 remainder 0.30 0.20 / / / / Example 7 Comparative 30 / 1.06 / 0.40 0.10 / 0.92 remainder / / 0.20 / / / Example 8 Comparative 30.0 / 1.07 / 0.40 0.10 / 0.92 remainder / / / 0.20 / / Example 9 Comparative 30.0 / 1.06 / 0.40 0.10 / 0.92 remainder / / / / 0.20 / Example 10 Comparative / 29.1 0.35 0.5 0.20 2.0 / 0.9 remainder 0.20 0.20 0.15 / / 0.03 Example 11

[0144] (3) FE-EPMA inspection: the perpendicularly oriented surface of the permanent magnet material was polished and inspected using a field emission electron probe micro-analyzer (FE-EPMA) (Japan Electronics Corporation (JEOL), 8530F). The distribution f Nd, Cu, Ti and other elements in the permanent magnet material was first determined by FE-EPMA surface scanning, and then the content of Cu and Ti 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.

[0145] The FE-EPMA inspection was performed on the permanent magnet material produced in Example 7, and the results are shown in Table 4 and FIG. 1 below. Wherein:

[0146] FIG. 1 shows the concentration distribution diagrams of Nd, Cu, and Ti, respectively, From FIG. 1, it can be seen that Ti-rich phase exists at the grain boundaries in addition to the diffuse distribution of Ti within the main phase. The Cu content in the Ti-rich phase is also higher than that in the main phase. In FIG. 1, point 1 is the main phase and point 2 is the Ti-rich phase.

[0147] Table 4 shows the results of the FE-EWA single-point quantitative analysis of this Ti-rich phase in FIG. 1, As can be seen from Table 4, in this Ti-rich phase, the Ti content is 1.8 times the Cu content by atomic percentage, and the amount of rare earth is about 21.3 at %. Similarly, during FE-SPMA inspection of other Examples, the presence of a high-Cu-high-Ti phase at grain boundaries can be observed, and the Ti content is 1.5 to 2 times the Cu content by atomic percentage, and a total rare earth amount of 18 to 30 at % (at % is the atomic percentage, specifically the percentage of atomic content of various elements)

TABLE-US-00004 TABLE 4 Phase (at %) Nd Tb Fe Co Cu Ti B composition Point 1 11.4 0.2 80.6 1.03 0.06 0.02 5.90 R.sub.2T.sub.14B Point 2 18.0 3.2 73.2 0.98 1.48 2.72 0.33 High-Cu- high-Ti phase

[0148] FE-EPNIA was performed for the Comparative Example 3, and the results are shown in FIG. 2, representing the concentration distribution diagrams of Nd, Cu, and Ti, respectively. From the results, it can be seen that Ti is diffusely distributed within the main phase and no high-Cu-high-Ti phase is formed at the grain boundaries. During the inspection of the other Comparative Examples, no high-Cu-high-Ti phase was observed at the grain boundaries of the permanent magnet materials.