R-Fe-B Series Permanent Magnet Materials, Manufacturing Methods, and Applications

Abstract

The present invention discloses an R-Fe-B-based permanent magnet material, its manufacturing method and applications. The above permanent magnet material has the performance of Br≧13.3 KGs, Hcj≧25.1 Koe, HAST weight loss ≦3 mg / cm² for 20 days 2 , and a bending strength >440 Mpa. By means of accurate formulation design and method design, on the premise of strictly controlling elements such as O, C, N, etc. in the permanent magnet material, elements such as Ti, Ga, Cu, etc. that are beneficial to the Hcj, weight loss performance, and mechanical properties of the permanent magnet material are contained in the grain boundary phase of the permanent magnet material. These elements are uniformly distributed in the grain boundary phase at a certain ratio, not only playing a role in refining the crystal grains, increasing the wettability and corrosion resistance of the grain boundaries, and preventing abnormal growth of the crystal grains, but also by combining the optimized jet mill powder-making process and the sintering process, improving the microstructure of the main phase and the grain boundary phase of the permanent magnet material, thereby manufacturing an R-Fe-B-based permanent magnet material with excellent comprehensive performance.

Description

Detailed Description of the Invention

[0001] This application claims the priority of a prior patent application with an application number of 202210576133.8 and a title of "R-Fe-B Series Permanent Magnet Material, Manufacturing Method and Application", which was filed by the applicant with the China National Intellectual Property Administration on May 24, 2022. The entire content of the prior application is incorporated herein by reference in its entirety.

[0002] 〔Technical Field〕 The present invention belongs to the technical field of R-Fe-B series permanent magnet materials, and particularly relates to R-Fe-B series permanent magnet materials, their manufacturing methods, and applications.

[0003] 〔Background Art〕 Sintered R-Fe-B series permanent magnets are widely used in fields such as power motors, computers, and electronic products due to their excellent magnetic performance. With the improvement of products, the requirements for the temperature coefficient of magnets in these fields are becoming even higher. In particular, with the development of related fields such as air conditioners and electric vehicles, the demand for the application of neodymium iron boron magnets in multiple fields is increasing, and the requirements for their performance are also becoming higher and higher.

[0004] At the same time, the most obvious drawback of R-Fe-B series sintered magnets compared with Sm-Co series permanent magnets is their poor corrosion resistance, which limits their application in high-temperature and high-humidity environments. Therefore, research on the corrosion resistance problem of R-Fe-B series sintered magnets has important significance. In particular, in recent years, with the improvement of environmental protection and energy conservation awareness around the world, high-performance R-Fe-B series sintered magnets with excellent corrosion resistance are urgently needed for permanent magnet motors such as environmental protection, energy conservation, and high-efficiency wind turbines applied in humid environments such as the seaside and grasslands.

[0005] However, currently, in the formulation of magnet materials in the prior art, the improvement of magnetic performance by each element of the neodymium iron boron magnetic material cannot be fully utilized, and it is impossible to obtain a magnetic material with high magnetic performance and relatively good weight loss performance and mechanical performance at the same time.

[0006] 〔Summary of the Invention〕 In order to improve the above problems, the present invention provides an R-Fe-B-based permanent magnet material, Br≧13.3 KGs, Hcj≧25.1 Koe, HAST weight loss for 20 days ≦ 3 mg / cm 2 , and has a bending strength > 440 Mpa. The present invention provides an R-Fe-B-based permanent magnet material.

[0007] According to an embodiment of the present invention, the HAST weight loss of the above permanent magnet material for 20 days ≦ 1 mg / cm 2 .

[0008] According to an embodiment of the present invention, the above R-Fe-B-based permanent magnet material has the following performance: Br is 13.3 - 15.0 KGs, Hcj is 25 - 34 Koe, the HAST weight loss for 20 days is 0.1 - 0.5 mg / cm 2 , and the bending strength is 445 - 470 Mpa.

[0009] According to an embodiment of the present invention, the composition of the above R-Fe-B-based permanent magnet material contains Ti and Ga, wherein the Ti content ≧ 0.2 wt% and the Ga content ≧ 0.2 wt%, and 1 < Ti / Ga < 2.

[0010] According to an embodiment of the present invention, the above R-Fe-B-based permanent magnet material has a composition of 100% by mass percentage, wherein R is 26.0 - 32.0%, RH is 0.3 - 4.0%, Co is 0.5 - 3.0%, Cu is 0.1 - 0.25%, Ga is 0.2 - 0.4%, Ti is 0.2 - 0.4%, Al is 0 - 0.4%, B is 0.95 - 1.05%, and the balance is Fe and unavoidable impurities. Among them, R is neodymium (Nd) and / or praseodymium (Pr), RH is dysprosium (Dy) and / or terbium (Tb), Among them, the mass percentages of the above element contents 1) 1 < Ti / Ga < 2, 2) 5 ≦ Co / Cu < 15, must satisfy the above relationships.

[0011] According to an embodiment of the present invention, the R-Fe-B-based permanent magnet material includes a grain boundary phase, wherein the components of the grain boundary phase are R a RH b Ti c Ga d Cu e Al F C Og Fe 残り and 33 ≦ a ≦ 45, 0.1 ≦ b ≦ 16, 3 ≦ c ≦ 12, 0.4 ≦ d ≦ 2, 0.3 ≦ e ≦ 2.0, 0.01 ≦ f ≦ 0.1, 0.4 ≦ g ≦ 16, a + b + c + d + e + f + g + remainder = 100, the mass ratio of R a RH b Ti c Ga d Cu e Al F C Og Fe 残り occupying the permanent magnet material is 6 to 11 wt%.

[0012] According to an embodiment of the present invention, the R is Nd or PrNd, and the content of the R is preferably 26.5% to 31.0%, preferably 26.5%, 27.0%, 27.5%, 28%, 28.5%, 29.0%, 29.5%, 30.0%, 30.5%, or 31%.

[0013] According to an embodiment of the present invention, the RH is at least one of Dy and Tb, and the RH content range is preferably 0.3% to 3.5%, for example, 0.5%, 0.8%, 1.0%, 1.3%, 1.5%, 1.8%, 2.5%, 2.8%, 3.0%, 3.1%, or 3.5%.

[0014] According to an embodiment of the present invention, the content of Co is 1.0 to 3.0%, preferably 0.5%, 1%, 1.5%, 2.0%, 2.5% or 3.0%.

[0015] According to an embodiment of the present invention, the content of Cu is 0.1 to 0.25%, preferably 0.1%, 0.12%, 0.15%, 0.17%, 0.18%, 0.2%, 0.23% or 0.25%.

[0016] According to an embodiment of the present invention, the content of Ga is 0.2 to 0.4%, preferably 0.2%, 0.25%, 0.3%, 0.35% or 0.4%.

[0017] According to an embodiment of the present invention, the content of Ti is 0.2 to 0.4%, preferably 0.2%, 0.25%, 0.28%, 0.30%, 0.32%, 0.35%, 0.38% or 0.40%.

[0018] According to an embodiment of the present invention, the content of Al is 0.05 to 0.35%, preferably 0.1%, 0.15%, 0.2%, 0.25%, 0.3% or 0.35%.

[0019] According to an embodiment of the present invention, the content of B is 0.97 to 1.03%, preferably 0.97%, 0.98%, 0.99%, 1.0%, 1.01%, 1.02% or 1.03%.

[0020] According to an embodiment of the present invention, the inevitable impurities are at least one of, for example, C, N, O, etc. Preferably, the oxygen content is 300 to 900 ppm, the carbon content is 400 to 800 ppm, and the nitrogen content is 200 to 600 ppm.

[0021] The present invention further provides a method for manufacturing a Re-Fe-B based permanent magnet material, which includes steps of smelting and casting, coarse pulverization, fine pulverization, forming, sintering, processing, and diffusion treatment of raw materials of the Re-Fe-B based permanent magnet material to obtain the Re-Fe-B based permanent magnet material.

[0022] According to an embodiment of the present invention, the above smelting and casting process is carried out in a medium-frequency vacuum induction rapid solidification melt spinning furnace. The linear velocity of the casting chill roll is 1 m / s to 2 m / s, the casting temperature is 1380 to 1480 °C, and the average value of the thickness of the flakes after smelting and casting is 0.20 to 0.30 mm.

[0023] According to an embodiment of the present invention, the above coarse pulverization process is carried out in a hydrogen pulverization furnace by steps of hydrogen absorption, dehydrogenation, and cooling treatment. The pressure of the above hydrogen absorption treatment is 90 to 110 KPa, the temperature of the dehydrogenation treatment is 550 to 620 °C, and the time of dehydrogenation is 3 to 6 h.

[0024] According to an embodiment of the present invention, the above fine pulverization is carried out by an inert gas jet mill. The above inert gas is, for example, nitrogen gas, argon gas, etc. Preferably, the oxygen content is controlled to be ≦50 ppm in the fine pulverization process, the particle size SMD of the particles is 2.3 to 2.7 μm, preferably 2.5 μm, X90 / X10 ≦ 4.5, and X100 ≦ 12.5 μm. In the present invention, when X90 / X10 ≦ 4.5 and X100 ≦ 12.5 μm, higher Br and Hcj can be obtained, and at the same time, the level of weight loss and bending strength are also improved.

[0025] According to an embodiment of the present invention, an antioxidant can be added in the fine pulverization process and mixed for 3 to 6 h. The mass of the antioxidant is 1 to 2% of the total mass of the permanent magnet material. The antioxidant is one or more selected from 1,3,5-trichlorotoluene, dibutylhydroxytoluene, and 4-hexylresorcinol. The above antioxidant has a lubricating function. By adopting the fine pulverization process, fine powder with a uniform particle size distribution can be produced. At the same time, because an inert gas jet mill is used, the nitrogen content of the powder is at a relatively low level.

[0026] According to an embodiment of the present invention, the above forming process is magnetic field orientation and pressure forming with ≧1.5 T. In the pressure process, the powder is in a press machine in a completely sealed state and is continuously filled with nitrogen gas for protection.

[0027] According to an embodiment of the present invention, the sintering process first degasses the green compact produced by the molding process in 2 to 10 temperature zones, then performs vacuum sintering, further performs sintering in an inert atmosphere, and finally cools it.

[0028] Preferably, the temperatures of the 2 to 10 temperature zones are different from each other. Preferably, the degassing process can be carried out at a temperature with an increasing gradient. Exemplarily, when the degassing process is sequentially carried out in 2 to 10 temperature zones, first perform the degassing process in the first temperature zone, then sequentially enter the next temperature zone. For example, perform the degassing process in the second temperature zone, perform the degassing process in the third temperature zone, or perform the degassing process in more temperature zones. For example, the temperature of the first temperature zone may be 200 to 380 °C, preferably 280 to 320 °C, for example 300 °C. The temperature of the second temperature zone may be higher than that of the first temperature zone, for example 450 to 720 °C, preferably 580 to 620 °C, for example 600 °C. The temperature of the third temperature zone may be higher than that of the second temperature zone, for example 750 to 1000 °C, preferably 880 to 920 °C, for example 900 °C. By adopting the degassing process of the present invention, elements such as C, N, and H in the antioxidant can be sequentially removed from the permanent magnet material.

[0029] Preferably, the temperature of the vacuum sintering is 1000 to 1020 °C, and the time of the vacuum sintering is 1 to 2 h.

[0030] Preferably, the temperature of the sintering in the inert atmosphere is 1030 to 1050 °C, the time of the sintering in the inert atmosphere is 2 to 4 h, and the pressure during sintering in the inert atmosphere is 10 to 30 KPa. The above inert atmosphere is, for example, nitrogen gas or argon gas.

[0031] Preferably, after the sintering in the inert atmosphere is completed, it can be cooled to 50 °C or below by using a blower at 100 KPa.

[0032] According to the embodiments of the present invention, in the above sintering process, the green compact produced by the forming process is put into a sintering furnace under nitrogen gas protection, and then decarburization degassing treatment is carried out for 1 to 3 h respectively through the first temperature range of 200 - 380 °C, the second temperature range of 450 - 720 °C, and the third temperature range of 750 - 1000 °C. Further, vacuum sintering is carried out at 1000 - 1020 °C for 1 - 2 h. Furthermore, argon gas at 10 - 30 KPa is filled, and pressure holding sintering treatment is carried out at 1030 - 1050 °C for 2 - 4 h. After that, argon gas is filled to about 100 KPa, and the blower is started to cool to 50 °C or lower.

[0033] By adopting the decarburization degassing treatment process, vacuum sintering, and pressure sintering process, the present invention can suppress elements such as C, N, and O in the permanent magnet material to a relatively low level, and at the same time, further improve the density and bending strength of the permanent magnet material.

[0034] According to the embodiments of the present invention, the above diffusion treatment is a grain boundary diffusion treatment, which is carried out according to the conventional process in this field, for example, Tb, Dy vapor diffusion. Among them, the temperature of the above diffusion treatment may be 850 - 950 °C, for example, 900 °C, and the diffusion time is 10 - 50 h, for example, 36 h. After the above diffusion treatment, it is necessary to carry out stress relief aging treatment, and the temperature may be 450 - 650 °C, for example, 550 °C, and the time is 3 - 6 h.

[0035] According to the embodiments of the present invention, the oxygen content of the above Re - Fe - B - based permanent magnet material is 300 - 900 ppm, the carbon content is 400 - 800 ppm, and the nitrogen content is 200 - 600 ppm.

[0036] The present invention further provides the application of the above Re - Fe - B - based permanent magnet material as the motor rotor magnetic steel in a motor.

[0037] 〔Advantageous Effects of the Present Invention〕 The present invention strictly controls elements such as O, C, N, etc. in the permanent magnet material through accurate formulation design and process design. On the premise of this strict control, in the grain boundary phase of the permanent magnet material, elements such as Ti, Ga, Cu, etc., which are beneficial to the Hcj, weight loss performance, and mechanical properties of the permanent magnet material, are contained. These elements are uniformly distributed in the grain boundary phase at a certain ratio, playing a role in refining the crystal grains, increasing the wettability and corrosion resistance of the grain boundaries, and preventing abnormal growth of the crystal grains. Moreover, by combining the optimized jet mill powder-making process and sintering process, the microstructure of the main phase and grain boundary phase of the permanent magnet material is improved, thereby manufacturing an R-Fe-B series permanent magnet material with excellent comprehensive performance. Under the conditions of Br≧13.3 KGs and Hcj≧25.1 Koe, the HAST weight loss of the permanent magnet material for 20 days is ≦3 mg / cm 2 , achieving excellent weight loss performance, flexural strength >440 Mpa, and excellent comprehensive performance.

[0038] 〔Brief Description of the Drawings〕 Figure 1 is a backscattered scanning electron microscope analysis diagram of the permanent magnet material in Example 1.

[0039] 〔Modes for Carrying Out the Invention〕 Hereinafter, in accordance with specific examples, the technical solution of the present invention will be described in more detail. It should be understood that the following examples are merely illustrative explanations and interpretations of the present invention, and should not be construed as limiting the scope of the claims of the present invention. Any technology realized based on the above content of the present invention is included within the scope of the claims of the present invention.

[0040] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products, or may be manufactured by known methods.

[0041] Examples 1 - 10 and Comparative Examples 1 - 9 The elemental mass percentages in the permanent magnet materials of Examples 1 - 10 and Comparative Examples 1 - 9 are shown in Table 1 below.

[0042]

Table 1

Table 2

[0043] The manufacturing methods of the R-Fe-B based permanent magnet materials in Examples 1 to 10 and Comparative Examples 1 to 6 are as follows.

[0044] 1) Smelting According to the formulation shown in Table 1, the prepared raw materials are taken and put into a crucible, and it is carried out in a medium-frequency vacuum induction rapid solidification melt spinning furnace. The linear velocity of the casting quench roll is 1.5 m / s, the casting temperature is 1450 °C, and the average value of the thickness of the smelted flakes is 0.25 mm.

[0045] 2) HD treatment (coarse grinding) Hydrogen storage, dehydrogenation, and cooling treatments are carried out in a hydrogen pulverization furnace. The pressure of the above hydrogen storage treatment is 100 KPa, the temperature of the dehydrogenation treatment is 580 °C, and the dehydrogenation time is 4.5 h.

[0046] 3) Jet mill (fine grinding) By optimizing the parameters of the jet mill grinding process, the oxygen content in the grinding process is ≤50 ppm, the particle size control SMD is 2.5 μm, X90 / X10 = 4.0, and X100 = 10 μm. To produce the powder, 1.5% of dibutylhydroxytoluene based on the total mass of the permanent magnet material needs to be added and mixed for 5 h.

[0047] 4) Molding 1.8 T magnetic field orientation pressure molding is adopted. During the pressing process, the powder is in a completely sealed press, and nitrogen gas is continuously filled for protection.

[0048] 5) Sintering The compacted powder was placed in a sintering furnace under a nitrogen gas protection atmosphere, and decarburization degassing treatments were carried out at 300 °C, 600 °C, and 900 °C for 2 h each. Further, vacuum sintering was carried out at 1015 °C for 1.5 h. Then, argon gas at 20 KPa was filled, and pressure holding sintering treatment was carried out at 1040 °C for 3 h. Thereafter, argon gas was filled to about 100 KPa, and the blower was started to cool it to 50 °C or lower.

[0049] 6) Diffusion The permanent magnet material needs to be further subjected to grain boundary diffusion treatment, and the treatment is carried out according to the usual Tb vapor diffusion process in this field. Among them, the temperature of the diffusion treatment is 900 °C, the diffusion time is 30 h, and after the diffusion treatment, stress relief aging treatment may be carried out, the temperature may be 550 °C, the time is 4 h, and the permanent magnet material was manufactured.

[0050] Comparative Example 7 3) Jet mill (fine grinding) By optimizing the parameters of the jet mill grinding process, the oxygen content in the grinding process is ≤50 ppm, the particle size control SMD is 2.5 μm, X90 / X10 = 5.0, and X100 = 25 μm. To manufacture the powder, it is necessary to add 1.5% of dibutylhydroxytoluene and mix for 5 h. The processes of the remaining compounding, smelting, HD, press molding, sintering, and diffusion are the same as those in Example 1.

[0051] Comparative Example 8 5) Sintering First, the compacted powder was placed in a sintering furnace under a nitrogen gas protection atmosphere, and decarburization degassing treatments were carried out at 600 °C and 900 °C for 2 h each. Further, vacuum sintering was carried out at 1015 °C for 1.5 h. Then, argon gas at 20 KPa was filled, and pressure holding sintering treatment was carried out at 1040 °C for 3 h. Thereafter, argon gas was filled to about 100 KPa, and the blower was started to cool it to 50 °C or lower.

[0052] The processes of the remaining compounding, smelting, HD, press molding, sintering, and diffusion are the same as those in Example 1.

[0053] Comparative Example 9 5) Sintering First, put the compacted powder into a sintering furnace under nitrogen gas protection, perform decarburization degassing treatment at 900 °C for 2 h respectively, then conduct vacuum sintering at 1015 °C for 1.5 h, further fill with argon gas at 20 KPa, and perform pressure holding sintering treatment at 1040 °C for 3 h. After that, fill with argon gas to about 100 KPa, start the blower and cool it to 50 °C or below.

[0054] The processes of the remaining blending, smelting, HD, press forming, sintering, and diffusion are the same as those in Example 1.

[0055] Take the permanent magnet materials produced in each of Examples 1 to 10 and Comparative Examples 1 to 9, measure their magnetic properties, weight loss performance, and bending strength, and the results are shown in Table 2 below.

[0056] The remanence (Br), coercivity (Hcj), and magnetic energy product (BH (max) ) in each of Examples 1 to 10 and Comparative Examples 1 to 9 of the present invention were detected for magnetic properties using the NIM-62000 type rare earth permanent magnet measurement system of the National Institute of Metrology. The weight loss performance adopted the D10-10 sample column, and a German HAST high-temperature and high-humidity test device (130 °C, 0.26 atm, 100% RH, 480 h) was used. The bending strength was tested using a three-point bending facility and in accordance with the standard of GB / T 14452-93 (three-point bending).

[0057]

Table 3

Table 4

[0058] As can be seen from the above table, through precise formulation design, the present invention incorporates elements such as Ti, Ga, and Cu, which are beneficial to the Hcj, weight loss performance, and mechanical properties of the permanent magnet material, into the grain boundary phase of the system permanent magnet material. These elements are uniformly distributed in the grain boundary phase at a certain ratio, playing a role not only in refining the crystal grains, increasing the wettability and corrosion resistance of the grain boundaries, and preventing abnormal growth of the crystal grains, but also, by combining the optimized jet mill powder process and sintering process, improving the microstructure of the main phase and grain boundary phase of the permanent magnet material. Moreover, through strict process design, the contents of O, C, and N in the permanent magnet material are strictly controlled, thereby manufacturing an R-Fe-B system permanent magnet material with excellent comprehensive performance. The elements O, C, and N occupy the effective neodymium-rich phase for high-end permanent magnet materials, embrittle the grain boundary phase, easily reduce the Hcj of the permanent magnet material, and reduce the strength. That is, through precise formulation design and process design, the present invention has produced a permanent magnet material with Br≧1.33 T, Hcj≧2000 KA / m, 20-day HAST weight loss≦0.5 mg / cm 2 , flexural strength>440 Mpa, and excellent comprehensive performance.

[0059] Figure 1 is a backscattered scanning electron microscope analysis diagram of the permanent magnet material in Example 1.

[0060] The grain boundary phases in different regions of Figure 1 were selected and subjected to EDS energy spectrum analysis at a magnification of 2000 times to obtain the content (mass percentage) of each element in the grain boundary. From Figure 1 and the results of the EDS energy spectrum analysis, the magnet of Example 1 is composed of an Nd2Fe 14 B main phase (gray area) and a grain boundary phase (silver-white area). Among them, the components of the grain boundary phase are Nd 33~45 Tb 0.1~1 Ti 4~8 Ga 0.4~1.5 Cu 0.3~1 Al 0.01~0.06 C O0.4~3 Fe 残り . The percentage of the area of the grain boundary phase in different regions occupying the total area of the selected microstructure observation region was calculated, and the area of the grain boundary phase / total area of the observation region was 6.2~8.9%, that is, it was found that the density of the above permanent magnet material is uniform.

[0061] In Table 3, the specific detection results of the grain boundary phase content are as follows.

[0062]

Table 5

[0063] As described above, the embodiments of the present invention have been exemplarily described. However, the scope of the claims of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without departing from the gist and principles of the present invention should all be included within the scope of the claims of the present invention.

Brief Description of the Drawings

[0064]

Figure 1

Claims

1. An R-Fe-B-based permanent magnet material, with Br≧13.3 KGs, Hcj≧25.1 Koe, HAST weight loss for 20 days ≦3 mg / cm 2 , and having a bending strength >440 Mpa, characterized by an R-Fe-B-based permanent magnet material.

2. The R-Fe-B-based permanent magnet material has Br of 13.3 - 15.0 KGs, Hcj of 25 - 34 Koe, HAST weight loss for 20 days of 0.1 - 0.5 mg / cm 2 , a bending strength of 445 - 470 Mpa, and preferably, the composition of the R-Fe-B-based permanent magnet material contains Ti and Ga, wherein the Ti content ≧0.2 wt%, the Ga content ≧0.2 wt%, and 1 < Ti / Ga < 2, characterized by the permanent magnet material according to Claim 1.

3. The R-Fe-B-based permanent magnet material contains, by mass percentage of 100%, R of 26.0 - 32.0%, RH of 0.3 - 4.0%, Co of 0.5 - 3.0%, Cu of 0.1 - 0.25%, Ga of 0.2 - 0.4%, Ti of 0.2 - 0.4%, Al of 0 - 0.4%, B of 0.95 - 1.05%, and the balance being Fe and unavoidable impurities, wherein R is neodymium (Nd) and / or praseodymium (Pr), RH is dysprosium (Dy) and / or terbium (Tb), among which, the mass percentages of the element contents 1) 1 < Ti / Ga < 2, 2) 5 ≦ Co / Cu < 15, and it is necessary to satisfy the relationship, characterized by the permanent magnet material according to Claim 1 or 2.

4. The R-Fe-B-based permanent magnet material contains a grain boundary phase, among which the composition of the grain boundary phase is R a RH b Ti c Ga d Cu e Al F C Og Fe 残り comprising, 33 ≦ a ≦ 45, 0.1 ≦ b ≦ 16, 3 ≦ c ≦ 12, 0.4 ≦ d ≦ 2, 0.3 ≦ e ≦ 2.0, 0.01 ≦ f ≦ 0.1, 0.4 ≦ g ≦ 16, and the R occupying the permanent magnet material a RH b Ti c Ga d Cu e Al F C Og Fe 残り the mass ratio thereof is 6 to 11 wt%, Preferably, the inevitable impurities are at least one of C, N, and O. Preferably, the oxygen content is 300 to 900 ppm, the carbon content is 400 to 800 ppm, and the nitrogen content is 200 to 600 ppm. The permanent magnet material according to any one of claims 1 to 3.

5. A method for manufacturing the permanent magnet material according to any one of claims 1 to 4, comprising the steps of smelting, casting, coarse pulverizing, fine pulverizing, molding, sintering, processing, and diffusion treating the raw materials of the Re-Fe-B based permanent magnet material to obtain the Re-Fe-B based permanent magnet material. Manufacturing method.

6. The coarse pulverization process is performed in a hydrogen pulverization furnace by performing hydrogen occlusion, dehydrogenation, and cooling treatments. The pressure of the hydrogen occlusion treatment is 90 to 110 KPa, the temperature of the dehydrogenation treatment is 550 to 620 °C, and the time of dehydrogenation is 3 to 6 h. Preferably, the fine pulverization is performed by an inert gas jet mill. The inert gas is, for example, nitrogen gas, argon gas, etc. Preferably, the oxygen content is controlled to be ≦ 50 ppm during the fine pulverization process, the particle size SMD of the particles is 2.3 to 2.7 μm, preferably 2.5 μm, preferably, X90 / X10 ≦ 4.5, and X100 ≦ 12.5 μm during the fine pulverization process. The method according to claim 5.

7. The sintering process is characterized in that it is carried out in steps of degassing the green compact produced by the molding process in 2 to 10 temperature zones, then vacuum sintering, then sintering in an inert atmosphere, and then cooling. The method according to claim 5 or 6.

8. The temperatures of the 2 to 10 temperature zones are different from each other. Preferably, the degassing process is carried out at a temperature with an increasing gradient. The method according to claim 7.

9. When the degassing process is sequentially carried out in 2 to 10 temperature zones, first, the degassing process is carried out in the first temperature zone, and then it sequentially enters the next temperature zone. For example, the degassing process is carried out in the second temperature zone and the third temperature zone, or the degassing process is carried out in more temperature zones. For example, the temperature of the first temperature zone is 200 to 380 °C, the temperature of the second temperature zone is higher than that of the first temperature zone and is 450 to 720 °C, and the temperature of the third temperature zone is higher than that of the second temperature zone and is 750 to 1000 °C. The method according to claim 7 or 8.

10. Application of the Re-Fe-B-based permanent magnet material according to any one of claims 1 to 4 as a motor rotor magnetic steel in a motor.

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