Modified rare earth permanent magnet material and preparation method thereof

Abstract

The invention provides a modified rare earth permanent magnet material and a preparation method thereof. The preparation method comprises the steps that S1, a base material and an alloy are prepared, the base material has the chemical formula shown in the formula (I) (RE1xGdyRE2100%-x-y) aM1bBcFe100%-a-b-c (I); the alloy has a chemical formula as shown in a formula (II), namely RE < 3 > 100%-dM < 2 > d (II), s2, alloy, a solvent and a binder are mixed, and slurry is obtained; and S3, coating the surface of a base material with the slurry, and performing diffusion annealing treatment to obtain the modified rare earth permanent magnet material. The preparation cost of the modified rare earth permanent magnet material is low, the modified rare earth permanent magnet material also has excellent high temperature resistance, the open-circuit irreversible magnetic flux loss at the high temperature of 100 DEG C does not exceed 5%, even the open-circuit irreversible magnetic flux loss at the high temperature of 120 DEG C does not exceed 5%, and the modified rare earth permanent magnet material also has high coercive force and can be used in high-end application fields such as permanent magnet motors.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth permanent magnetic materials, and in particular to a modified rare earth permanent magnetic material and a preparation method thereof. Background Art

[0002] With the rapid development of new energy vehicles, wind power generation, green home appliances and other fields, people's demand for rare earth permanent magnet materials is increasing. Rare earth resources are limited. The rapid development of the rare earth permanent magnet industry has led to the overuse of some rare earth elements (Pr, Nd, Dy, Tb), while high-abundance rare earth elements (La, Ce, Y) are constantly accumulating. High-abundance rare earth permanent magnet materials can not only reduce the cost of raw materials, but also achieve a comprehensive and balanced utilization of rare earth resources. However, Ce 2 Fe 14 The intrinsic performance of B is much lower than that of Nd 2 Fe 14 B. Directly adding Ce into NdFeB magnets will lead to a significant decrease in the magnetic properties of the magnets.

[0003] Chinese patent application CN113782290A discloses the use of a dual-main-phase process to prepare a high Ce dual-main-phase content high magnetic energy product magnet to improve the magnetic properties of the magnet, but the magnetic properties of the magnet produced are basically N level and below, which makes it difficult to apply it to the field of permanent magnet motors with high thermal stability requirements.

[0004] Chinese patent application CN113130200A discloses a process of using pressurized heat treatment to improve the magnetic properties of high-abundance rare earth permanent magnet materials, but pressurized heat treatment is difficult to apply in large-scale production.

[0005] Chinese patent application CN109637768A uses rare earth Y to prepare rare earth permanent magnet materials, but the smelting cost of rare earth Y is relatively high, and its raw material price is much higher than rare earth La and rare earth Ce, so its cost reduction effect is not obvious.

[0006] In order to solve the above technical problems, it is urgent to research and develop a new type of modified rare earth permanent magnet material and its preparation method, which is of great significance for improving the temperature resistance and magnetic properties of rare earth permanent magnet materials. Summary of the invention

[0007] The main purpose of the present invention is to provide a modified rare earth permanent magnet material and a preparation method thereof, so as to solve the problems of poor high temperature resistance and high preparation cost of rare earth permanent magnet materials in the prior art.

[0008] In order to achieve the above object, the present invention provides a method for preparing a modified rare earth permanent magnet material, the method comprising: step S1, preparing a substrate and an alloy, the substrate having a chemical formula shown in formula (I), (RE 1 xG y RE 2 100％-x-y ) a M 1 b B c Fe 100％-a-b-c (I), where RE 1 As the first rare earth element, RE 1 Selected from La and / or Ce elements, RE 2 The second rare earth element, RE 2 One or more selected from Pr, Nd, Dy, Tb, Ho, Y elements, M 1 One or more selected from Ga, Co, Al, Cu, Nb, Zr, Ti, x is 5-50%, y is 0.5-1.5 times of x, a is 28-33%, b is 0.5-5%, c is 0.85-1%; the alloy has the chemical formula shown in formula (II), RE 3 100％-d M 2 d (II), where RE 3 As the third rare earth element, RE 3 One or more selected from Pr, Nd, Dy, Tb, Ho elements, M 2 One or more elements selected from Ga, Co, Al, Cu, Nb, Zr, and Ti, d is 0.2-50%; step S2, mixing the alloy, solvent, and binder to obtain slurry; step S3, coating the slurry on the surface of the substrate, and obtaining a modified rare earth permanent magnet material after diffusion annealing.

[0009] Further, x is 10 to 40%, y is 0.5 to 1.5 times of x, a is 29 to 32%, b is 1 to 3%, and c is 0.88 to 0.96%.

[0010] Furthermore, d is 4 to 30%.

[0011] Furthermore, based on the total weight of the substrate and the alloy, the weight percentage of the alloy does not exceed 2wt%; preferably, the weight ratio of the alloy to the substrate is (1-15):(900-1000).

[0012] Furthermore, RE 1 is a combination of La and Ce; preferably, RE 1 It is a combination of La and Ce, and the weight ratio of La to Ce is (0.8-1.2):(2-9.5); RE 2 is Nd, or a combination of Pr and Nd, or a combination of Pr, Nd and Dy; preferably, RE 2 is a combination of Pr and Nd; more preferably, RE2 It is a combination of Pr and Nd, and the weight ratio of Pr to Nd is 1:(2-8); M 1 is a combination of Co, Al, Cu and Ga, or a combination of Co, Cu, Ga, or a combination of Co, Cu, Al; preferably, M 1 is a combination of Co, Al, Cu and Ga; more preferably, M 1 It is a combination of Co, Al, Cu and Ga, and the weight ratio of Co, Al, Cu and Ga is (0.5-1.5):(0.05-0.5):(0.05-0.5):(0.05-0.5); RE 3 is Dy, Tb or Pr; preferably, RE 3 Dy or Tb; M 2 is a combination of Co and Cu, or a combination of Co and Al; preferably, M 2 is a combination of Co and Cu; more preferably, M 2 It is a combination of Co and Cu, and the weight ratio of Co to Cu is (0.5-1.5):(0.05-0.5).

[0013] Furthermore, the solid content of the slurry is 50 to 90 wt %.

[0014] Furthermore, the solvent is selected from one or more of the group consisting of methanol, ethanol, No. 120 gasoline, styrene, perchloroethylene, trichloroethylene, ethylene glycol ether, and triethanolamine, and / or the binder is selected from one or more of the group consisting of epoxy resin, phenolic resin, nitrocellulose, PVC glue, PVB, and PVA.

[0015] Furthermore, the coating is performed by spraying, printing or magnetron sputtering.

[0016] Furthermore, the diffusion annealing treatment is performed at a temperature of 850 to 950° C. and for a time of 3 to 60 hours.

[0017] In order to achieve the above-mentioned purpose, another aspect of the present invention further provides a modified rare earth permanent magnet material, which is prepared by the preparation method of the modified rare earth permanent magnet material provided in the present application.

[0018] By applying the technical solution of the present invention, compared with the traditional NdFeB permanent magnet material, the substrate used in the present application contains the first rare earth element RE 1 and Gd. The first rare earth element RE 1 It is a high-abundance rare earth with low price. It uses the first rare earth element RE 1Substituting praseodymium and neodymium can reduce the cost of raw materials, and is conducive to the balanced development and utilization of rare earth resources and the sustainable development of the rare earth permanent magnet industry. The introduction of Gd elements can effectively improve the temperature resistance of modified rare earth permanent magnet materials, and the introduction of Gd elements can inhibit the CeFe 2 The precipitation of the first rare earth element RE can improve the crystal structure of the modified rare earth permanent magnet material, thereby significantly improving the magnetic properties of the modified rare earth permanent magnet material. 1 The Gd element is introduced into the substrate of the present invention to play a role in RE 1 The synergistic effect with the Gd element can more effectively improve the temperature resistance and magnetic properties of the modified rare earth permanent magnet material by controlling the dosage ratio of the two (strictly limiting the value range of x and the ratio of x to y in the general formula) while reducing the preparation cost.

[0019] Compared with other types, the third rare earth element RE of the specific type of this application is used 3 and M 2 It can improve the microstructure and grain boundary phase distribution of the material, and better enhance the intrinsic coercivity of the material without almost reducing the remanence of the material; under the condition of the same intrinsic coercivity, the open-circuit irreversible flux loss of the modified rare earth permanent magnet material is lower, that is, the high-temperature stability is better.

[0020] A slurry containing an alloy is coated on the surface of the above-mentioned substrate, and the above-mentioned modified rare earth permanent magnet material provided in the present application is obtained by a diffusion annealing process, so that the modified rare earth permanent magnet material contains both the substrate of the above-mentioned specific composition (strictly controlling the weight percentage of each element in the general formula (I)) and the alloy of the specific composition (strictly controlling the weight percentage of each element in the general formula (II)). On the one hand, this is conducive to improving the high temperature resistance of the modified rare earth permanent magnet material, so that its open circuit irreversible flux loss under high temperature conditions of 100°C does not exceed 5%, or even does not exceed 5% under high temperature conditions of 120°C; on the other hand, it is also conducive to improving the coercive force of the modified rare earth permanent magnet material, so that it can reach the H grade, SH grade, or even UH grade specified in GB / T13560-2017, so that it can be used in high-end application fields such as permanent magnet motors. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0022] As described in the background technology, the existing rare earth permanent magnet materials have the problems of poor high temperature resistance and high preparation cost. In order to solve the above technical problems, the present application provides a method for preparing a modified rare earth permanent magnet material, the preparation method comprising: step S1, preparing a substrate and an alloy respectively, the substrate having a chemical formula shown in formula (I), (RE1 x G y RE 2 100％-x-y ) a M 1 b B c Fe 100％-a-b-c (I), where RE 1 As the first rare earth element, RE 1 Selected from La and / or Ce elements, RE 2 The second rare earth element, RE 2 One or more selected from Pr, Nd, Dy, Tb, Ho, Y elements, M 1 One or more selected from Ga, Co, Al, Cu, Nb, Zr, Ti, x is 5-50%, y is 0.5-1.5 times of x, a is 28-33%, b is 0.5-5%, c is 0.85-1%; the alloy has the chemical formula shown in formula (II), RE 3 100％-d M 2 d (II), where RE 3 As the third rare earth element, RE 3 One or more selected from Pr, Nd, Dy, Tb, Ho elements, M 2 One or more elements selected from Ga, Co, Al, Cu, Nb, Zr, and Ti, d is 0.2-50%; step S2, mixing the alloy, solvent, and binder to obtain slurry; step S3, coating the slurry on the surface of the substrate, and obtaining a modified rare earth permanent magnet material after diffusion annealing.

[0023] Compared with the traditional NdFeB permanent magnet material, the substrate used in this application contains the first rare earth element RE 1 and Gd. The first rare earth element RE 1 It is a high-abundance rare earth with low price. It uses the first rare earth element RE 1 Substituting praseodymium and neodymium can reduce the cost of raw materials, and is conducive to the balanced development and utilization of rare earth resources and the sustainable development of the rare earth permanent magnet industry. The introduction of Gd elements can effectively improve the temperature resistance of modified rare earth permanent magnet materials, and the introduction of Gd elements can inhibit the CeFe 2 The precipitation of the first rare earth element RE can improve the crystal structure of the modified rare earth permanent magnet material, thereby significantly improving the magnetic properties of the modified rare earth permanent magnet material. 1 The Gd element is introduced into the substrate of the present invention to play a role in RE 1The synergistic effect with the Gd element can more effectively improve the temperature resistance and magnetic properties of the modified rare earth permanent magnet material by controlling the dosage ratio of the two (strictly limiting the value range of x and the ratio of x to y in the general formula) while reducing the preparation cost.

[0024] Compared with other types, the third rare earth element RE of the specific type of this application is used 3 and M 2 It can improve the microstructure and grain boundary phase distribution of the material, and better enhance the intrinsic coercivity of the material without almost reducing the remanence of the material; under the condition of the same intrinsic coercivity, the open-circuit irreversible flux loss of the modified rare earth permanent magnet material is lower, that is, the high-temperature stability is better.

[0025] A slurry containing an alloy is coated on the surface of the above-mentioned substrate, and the above-mentioned modified rare earth permanent magnet material provided in the present application is obtained by a diffusion annealing process, so that the modified rare earth permanent magnet material contains both the substrate of the above-mentioned specific composition (strictly controlling the weight percentage of each element in the general formula (I)) and the alloy of the specific composition (strictly controlling the weight percentage of each element in the general formula (II)). On the one hand, this is conducive to improving the high temperature resistance of the modified rare earth permanent magnet material, so that its open circuit irreversible flux loss under high temperature conditions of 100°C does not exceed 5%, or even does not exceed 5% under high temperature conditions of 120°C; on the other hand, it is also conducive to improving the coercive force of the modified rare earth permanent magnet material, so that it can reach the H grade, SH grade, or even UH grade specified in GB / T13560-2017, so that it can be used in high-end application fields such as permanent magnet motors.

[0026] Although the grain boundary diffusion technology used in the present invention increases the cost to a certain extent, the preparation cost is still greatly reduced compared with the conventional process magnets with similar magnetic properties. In addition, the preparation method provided by the present invention is simple and feasible, and can be implemented without the need for additional equipment.

[0027] In a preferred embodiment, x is 10-40%, y is 0.5-1.5 times of x, a is 29-32%, b is 1-3%, and c is 0.88-0.96%. 1 weight percentage), the ratio between x and y (RE 1 The ratio of the amount of Gd element) and the value ranges of a, b, and c include but are not limited to the above ranges. Further limiting them to the above ranges is conducive to better play of RE 1 The synergistic effect with the Gd element is beneficial to improving the temperature resistance and magnetic properties of the modified rare earth permanent magnet material, and is beneficial to improving the crystal structure of the modified rare earth permanent magnet material; at the same time, it is also beneficial to better exert the synergistic effect of the above-mentioned elements, thereby reducing the open circuit irreversible flux loss of the material under high temperature conditions and improving the coercive force of the material.

[0028] In a preferred embodiment, x is 20-40 wt%, and y is 0.5-1.5 times of x. Compared with other ranges, the value of x (RE 1 The weight percentage of x and y (RE 1 The amount ratio of Gd element is limited to the above range, which is beneficial to better play the role of RE 1 The synergistic effect with the Gd element is beneficial to improving the temperature resistance and magnetic properties of the modified rare earth permanent magnet material, and is beneficial to improving the crystal structure of the modified rare earth permanent magnet material; at the same time, it is also beneficial to better exert the synergistic effect of the above-mentioned elements, thereby reducing the open circuit irreversible flux loss of the material under high temperature conditions and improving the coercive force of the material.

[0029] In order to further reduce the open circuit irreversible flux loss of the modified rare earth permanent magnet material, while further improving its coercive force and further maintaining the remanence at a higher level, in a preferred embodiment, d is 4-30%.

[0030] In a preferred embodiment, the weight percentage of the alloy does not exceed 2wt% based on the total weight of the substrate and the alloy. The weight percentage of the second alloy includes but is not limited to the above range, and limiting it within the above range is conducive to better exerting the synergistic effect of the two, helping to reduce the open circuit irreversible magnetic flux loss, and at the same time helping to improve the coercive force, thereby helping to improve the high temperature resistance of the modified rare earth permanent magnet material.

[0031] In a preferred embodiment, the weight ratio of the alloy to the substrate is (1-15): (900-1000). The weight ratio of the alloy to the substrate includes but is not limited to the above range. Limiting it within the above range is conducive to the synergistic effect of the two, which is conducive to reducing the open circuit irreversible flux loss and improving its coercive force, thereby improving the high temperature resistance and magnetic properties of the modified rare earth permanent magnet material, making it more suitable for high-end application fields such as permanent magnet motors.

[0032] In a preferred embodiment, RE 1 is a combination of La and Ce; preferably, RE 1 The first rare earth element RE of the preferred type is used in comparison with other types. 1 Replacing the Nd element in traditional NdFeB magnets is beneficial to significantly reduce the cost of modified rare earth permanent magnet materials, and is also beneficial to maintaining a high level of magnetic properties while improving their high temperature resistance.

[0033] In a preferred embodiment, RE 2It is Nd, or a combination of Pr and Nd, or a combination of Pr, Nd and Dy. Compared with other types, using the above preferred types of RE' elements as doping elements is beneficial to improving the high temperature resistance and magnetic properties of the modified rare earth permanent magnet material.

[0034] In order to further improve the high temperature resistance and magnetic properties of the modified rare earth permanent magnet material, preferably, RE 2 is a combination of Pr and Nd; more preferably, RE 2 It is a combination of Pr and Nd, and the weight ratio of Pr to Nd is 1:(2~8).

[0035] In a preferred embodiment, M 1 It is a combination of Co, Al, Cu and Ga, or a combination of Co, Cu, Ga, or a combination of Co, Cu, Al. Compared with other types, using the above preferred types of M elements as doping elements is beneficial to reducing the cost of modified rare earth permanent magnet materials, and is also beneficial to improving their high temperature resistance and magnetic properties.

[0036] In order to further improve the high temperature resistance and magnetic properties of the modified rare earth permanent magnet material, preferably, M 1 is a combination of Co, Al, Cu and Ga; more preferably, M 1 It is a combination of Co, Al, Cu and Ga, and the weight ratio of Co, Al, Cu and Ga is (0.5-1.5):(0.05-0.5):(0.05-0.5):(0.05-0.5).

[0037] In a preferred embodiment, RE 3 is Dy, Tb or Pr; preferably, RE 3 Compared with other types, the third rare earth element RE of the preferred type is used. 3 As the second alloy component, it is beneficial to reduce open circuit irreversible flux loss and improve coercivity, thereby significantly improving the high temperature resistance and magnetic properties of modified rare earth permanent magnet materials, making them more suitable for high-end applications such as permanent magnet motors.

[0038] In a preferred embodiment, M 2 is a combination of Co and Cu, or a combination of Co and Al; preferably, M 2 is a combination of Co and Cu; more preferably, M 2 It is a combination of Co and Cu, and the weight ratio of Co to Cu is (0.5-1.5):(0.05-0.5). Compared with other types, the preferred type of M 2 It is beneficial to improve the microstructure and grain boundary phase distribution of the material, and is beneficial to better enhance the intrinsic coercivity of the material without reducing the remanence of the material.

[0039] In a preferred embodiment, the solid content of the slurry is 50-90wt%. The solid content of the slurry includes but is not limited to the above range. Limiting it to the above range is convenient for coating processing, which is beneficial to improving the uniformity of the alloy dispersion in the slurry, thereby facilitating the uniform and stable diffusion effect. Preferably, the solid content of the slurry is 70-90wt%.

[0040] In a preferred embodiment, the solvent includes, but is not limited to, one or more of the group consisting of methanol, ethanol, No. 120 gasoline, styrene, perchloroethylene, trichloroethylene, ethylene glycol ether, and triethanolamine. The types of solvents include, but are not limited to, the above range, and limiting them to the above range is conducive to further improving the dispersibility of the alloy in the slurry.

[0041] In a preferred embodiment, the binder includes, but is not limited to, one or more of the group consisting of epoxy resin, phenolic resin, nitrocellulose, PVC glue, PVB and PVA. Compared with other types, the use of the above preferred types of binders is conducive to improving the adhesion of the slurry on the surface of the substrate, thereby facilitating diffusion annealing treatment, thereby facilitating improving the magnetic properties such as the intrinsic coercivity of the modified rare earth permanent magnet material.

[0042] In a preferred embodiment, the coating is performed by spraying, printing or magnetron sputtering. Compared with other methods, the coating by the above method is easier to control the coating amount of the slurry, thereby being beneficial to improving the comprehensive properties such as magnetic properties of the modified rare earth permanent magnet material.

[0043] In a preferred embodiment, the temperature of the diffusion annealing treatment is 850-950°C and the time is 3-60 hours. The temperature and time of the diffusion annealing treatment include but are not limited to the above ranges, and limiting them within the above ranges is conducive to further improving the diffusion of the rare earth elements in the first alloy phase, and is conducive to further improving the intrinsic coercivity of the modified rare earth permanent magnet material.

[0044] The second aspect of the present application also provides a modified rare earth permanent magnet material, which is prepared by the preparation method of the modified rare earth permanent magnet material provided by the present application. The preparation cost of the modified rare earth permanent magnet material prepared by the present application is low, and the modified rare earth permanent magnet material also has excellent high temperature resistance, and its open circuit irreversible flux loss under high temperature conditions of 100°C does not exceed 5%, and even does not exceed 5% under high temperature conditions of 120°C. At the same time, it also has a high coercive force, which can reach the H grade, SH grade, and even UH grade specified in GB / T 13560-2017, and can be used in high-end application fields such as permanent magnet motors.

[0045] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0046] It should be noted that the preparation process of the substrate in the examples and comparative examples of the present application includes: 1 x G y RE 2 100％-x-y ) a M 1 b B c Fe 100％-a-b-c (I) Metal raw materials are prepared by weight percentage, and a casting alloy is prepared in a vacuum rapid solidification melting furnace; then hydrogen crushing (HD) and jet milling (JM) are used to obtain magnetic powder with an average particle size of 2.5 to 4 μm; a magnetic field of more than 1.5 T is used for orientation and pressure is applied to obtain a green body; the green body is placed in a vacuum sintering furnace and sintered at 1000 to 1100° C. to obtain a NdFeB blank, and the blank is processed into a 40 mm×40 mm×5 mm (5 mm is the orientation direction) block as a substrate for standby use.

[0047] The preparation process of the alloy in the examples and comparative examples of the present application includes: 3 100％-d M 2 d (II) The metal raw materials are mixed in weight percentage to prepare a casting alloy in a vacuum rapid solidification melting furnace; and then hydrogen crushing (HD) and jet milling (JM) are used to obtain magnetic powder with an average particle size of 3 to 5 μm as alloy powder for diffusion, which is then set aside.

[0048] Example 1

[0049] A method for preparing a modified rare earth permanent magnetic material, comprising:

[0050] (1) Preparation of substrate: According to (Ce 15 G 15 Nd 70 ) 31 Co 0.5 Al 0.3 Cu 0.15 Ga 0.2 B 0.95 Fe 66.9 The metal raw materials are prepared by weight percentage, and a casting alloy is prepared by a vacuum rapid solidification melting furnace; then, hydrogen crushing (HD) and jet milling (JM) are used to obtain magnetic powder with an average particle size of 3.1 μm; a magnetic field of more than 1.5 T is used for orientation and pressure application to obtain a green body; the green body is placed in a vacuum sintering furnace and sintered at 1080° C. to obtain a NdFeB blank, and the blank is processed into a 40×40×5 (orientation direction) block as a substrate for standby use;

[0051] (2) Preparation of alloy powder: According to Dy 80 Co 10 Cu 10 The metal raw materials are mixed in weight percentage, and a casting alloy is prepared in a vacuum rapid solidification melting furnace; then, magnetic powder with an average particle size of 3 to 5 μm prepared by hydrogen crushing (HD) + jet milling (JM) is used as alloy powder for diffusion;

[0052] (3) mixing the alloy, ethanol and PVC glue to obtain a slurry with a solid content of 80 wt %, wherein the weight ratio of the alloy, ethanol and PVC glue is 1:1.5:0.05;

[0053] (4) The slurry is coated on the surface of the substrate by spraying, and then diffused and annealed at 900°C for 10 hours in a vacuum diffusion furnace to form The modified rare earth permanent magnet material is cylindrical (5 mm in the orientation direction). The weight ratio of the substrate to the alloy is 1:0.005. The weight percentage of the alloy is 0.5wt% based on the total weight of the substrate and the alloy.

[0054] Example 2

[0055] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 1.

[0056] The difference from Example 1 is that the substrate is (Ce 20 La 5 G 20 Nd 55 ) 31 Co 0.5 Al 0.3 Cu 0.15 Ga 0.2 B 0.95 Fe 66 .9. x is 25%, y is 20%, a is 31%, b is 1.15%, and c is 0.95%.

[0057] Example 3

[0058] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 1.

[0059] The difference from Example 1 is that the substrate is (Ce 5 G 5 Nd 90 ) 31 Co 0.5 Al 0.1 Cu 0.15 Ga 0.2 B 0.95 Fe 67.1, x is 5%, y is 5%, a is 31%, b is 0.95%, c is 0.95%, and the alloy is Tb 80 Co 10 Cu 10 , d is 20%.

[0060] Example 4

[0061] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 1.

[0062] The difference from Example 1 is that the substrate is (Ce 30 La 10 G 20 Pr 5 Nd 35 ) 31 Co 0.5 Al 0.4 Cu 0.15 Ga 0.2 B 0.95 Fe 66.8 , x is 40%, y is 20%, a is 31%, b is 1.25%, c is 0.95%, and the alloy is Pr 80 Co 10 Cu 10 , d is 20%.

[0063] Example 5

[0064] The difference from Example 1 is that during the preparation of the substrate, (Ce 5 G 7.5 Nd 87.5 ) 31 Co 0.5 Al 0.3 Cu 0.15 Ga 0.2 B 0.95 Fe 66.9 Metal raw materials are formulated in weight percentage.

[0065] Example 6

[0066] The difference from Example 1 is that during the preparation of the substrate, (Ce 50 G 25 Nd 25 ) 31 Co 0.5 Al 0.3 Cu 0.15 Ga 0. 2 B 0.95 Fe 66.9 Metal raw materials are formulated in weight percentage.

[0067] Example 7

[0068] The difference from Example 1 is that during the preparation of the substrate, (Ce 10 G 10 Nd 80 ) 31 Co 0.5 Al 0.3 Cu 0.15 Ga 0. 2 B 0.95 Fe 66.9 Metal raw materials are formulated in weight percentage.

[0069] Example 8

[0070] The difference from Example 1 is that during the preparation of the substrate, (Ce 40 G 40 Nd 20 ) 31 Co 0.5 Al 0.3 Cu 0.15 Ga 0. 2 B 0.95 Fe 66.9 Metal raw materials are formulated in weight percentage.

[0071] Example 9

[0072] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 1.

[0073] The difference from Example 1 is that the composition of the substrate is different, which is (Ce 15 G 15 Nd 70 ) 31 Co 0.5 Cu 0.15 Ti 0.1 B 0.95 Fe 67.3 , where x is 15%, y is 15%, a is 31%, b is 0.75%, and c is 0.95%.

[0074] Example 10

[0075] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 4.

[0076] The difference from Example 4 is that the composition of the substrate is different, which is (Ce 15 G 15 Nd 70 ) 31 Co 0.5 Cu 0.15 Zr0.1 Ti 0. 1 B 0.95 Fe 67.2 , where x is 15%, y is 15%, a is 31%, b is 0.85%, and c is 0.95%.

[0077] Embodiment 11

[0078] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 4.

[0079] The difference from Example 4 is that the alloy composition is different, which is Ho 50 Co 25 Cu 25 , d is 50%. The remaining steps are the same as those in Example 4.

[0080] Example 12

[0081] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 4.

[0082] The difference from Example 4 is that the alloy composition is different, which is Ho 99.8 Co 0.1 Cu 0.1 , d is 0.2%. The remaining steps are the same as those in Example 4.

[0083] Example 13

[0084] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 4.

[0085] The difference from Example 4 is that the weight ratio of the alloy to the substrate is 1:1000.

[0086] Embodiment 14

[0087] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 4.

[0088] The difference from Example 4 is that the weight ratio of the alloy to the substrate is 15:900.

[0089] Embodiment 15

[0090] The modified rare earth permanent magnet material was prepared by the same preparation process as in Example 4.

[0091] The difference from Example 4 is that the weight ratio of the alloy to the substrate is 1:50.

[0092] Comparative Example 1

[0093] The difference from Example 4 is that the substrate is directly processed into (5mm is the orientation direction) Cylindrical modified rare earth permanent magnet material.

[0094] Comparative Example 2

[0095] The difference from Example 4 is that there is no Gd element in the composition of the substrate. The substrate is (Ce 30 La 10 Pr 5 Nd 35 ) 31 Co 0.5 Al 0.4 Cu 0.15 Ga 0.2 B 0.95 Fe 66.8 .

[0096] Comparative Example 3

[0097] The difference from Example 1 is that: x in the substrate is 50%, that is, during the preparation of the substrate, (Ce 50 Nd 50 ) 31 Co 0. 5 Al 0.3 Cu 0.15 Ga 0.2 B 0.95 Fe 66.9 Metal raw materials are formulated in weight percentage.

[0098] All the above examples and comparative examples of this application are (5mm is the orientation direction) The cylinder adopts NIM-2000 permanent magnet magnetic property testing device to test magnetic properties; EF5+ Helmholtz coil is used to test magnetic flux and calculate irreversible magnetic flux loss.

[0099] The method for determining the open circuit irreversible flux loss is as follows: magnetize the magnet sample, use the EF5 magnetic moment tester of Magnet Physic Company of Germany to measure the magnetic moment of the sample and record M 1 ; Heat the high-precision high-temperature oven to the measurement temperature (100℃ or 120℃), then put the sample into the oven and keep it warm for 2h (note that there should be no magnetic conductor within 100mm around the sample); take out the sample, cool it to room temperature, and measure the sample magnetic moment M again 2 , the calculation formula of open circuit irreversible flux loss is (M 1 -M 2 ) / M 1 ×100%.

[0100] Table 1

[0101]

[0102] From the above description, it can be seen that the above-mentioned embodiment of the present invention achieves the following technical effects: a slurry containing an alloy is coated on the surface of the above-mentioned substrate, and the above-mentioned modified rare earth permanent magnet material provided by the present application is obtained by a diffusion annealing process, so that the modified rare earth permanent magnet material contains both the substrate of the above-mentioned specific composition (strictly controlling the weight percentage of each element in the general formula (I)) and the alloy of the specific composition (strictly controlling the weight percentage of each element in the general formula (II)). On the one hand, this is conducive to improving the high temperature resistance of the modified rare earth permanent magnet material, so that its open circuit irreversible flux loss under high temperature conditions of 100°C does not exceed 5%, or even does not exceed 5% under high temperature conditions of 120°C; on the other hand, it is also conducive to improving the coercive force of the modified rare earth permanent magnet material, so that it can reach the H grade, SH grade, or even UH grade specified in GB / T 13560-2017, so that it can be used in high-end application fields such as permanent magnet motors.

[0103] Example 1 uses 15% Ce to replace the traditional rare earth Nd element, and the open circuit irreversible flux loss (under 120°C conditions) of the prepared magnet sample is only 0.3%, which can be used in many permanent magnet motor fields and has a wide range of applications. Example 2 increases the substitution amount of Ce elements to 25%, and the open circuit irreversible flux loss of the magnet sample is 2.34%, which can be applied to fields with open circuit irreversible flux loss ≤3%, and can still be applied to some permanent magnet motor fields. The substitution amount of Example 3 is relatively small, only 5%. After using this technology, the various magnetic performance indicators of the magnet sample are very good, and it belongs to high-performance NdFeB magnets. The substitution amount of Example 4 is 40%. After using this technology, the open circuit irreversible flux loss is ≤5%, which can be used for permanent magnet motors with lower thermal stability requirements.

[0104] By comparing Example 4 and Comparative Example 1, it can be seen that Comparative Example 1 does not adopt the grain boundary diffusion technology of the present application, that is, does not perform diffusion annealing treatment, has poor magnetic properties, and can only be used in low-end application fields.

[0105] By comparing Example 4 and Comparative Example 2, it can be seen that the Gd element is not introduced into the substrate of Comparative Example 2, and the open-circuit irreversible flux loss of the prepared magnet sample is much greater than that of Example 4, which has a greater risk of being used in permanent magnet motors.

[0106] Although the grain boundary diffusion technology used in the present invention increases the cost to a certain extent, the preparation cost is still greatly reduced compared with the conventional process magnets with similar magnetic properties. In addition, the preparation method provided by the present invention is simple and feasible, and can be implemented without the need for additional equipment.

[0107] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a modified rare earth permanent magnetic material, It is characterized in that The preparation method comprises: Step S1, preparing a substrate and an alloy respectively, wherein the substrate has a chemical formula shown in formula (I), (RE 1 x G y RE 2 100％-x-y ) a M 1 b B c Fe 100％-a-b-c (I), where RE 1 is the first rare earth element, the RE 1 Selected from La and / or Ce elements, RE 2 As the second rare earth element, the RE 2 One or more selected from Pr, Nd, Dy, Tb, Ho, Y elements, M 1 One or more selected from Ga, Co, Al, Cu, Nb, Zr, Ti elements, x is 5-50%, y is 0.5-1.5 times of x, a is 28-33%, b is 0.5-5%, c is 0.85-1%; The alloy has a chemical formula shown in formula (II), RE 3 100％-d M 2 d (II), where RE 3 As the third rare earth element, the RE 3 One or more selected from Pr, Nd, Dy, Tb, Ho elements, M 2 One or more selected from Ga, Co, Al, Cu, Nb, Zr, Ti, d is 0.2-50%; Step S2, mixing the alloy, solvent and binder to obtain slurry; Step S3, coating the slurry on the surface of the substrate, and obtaining the modified rare earth permanent magnet material after diffusion annealing.

2. The method for preparing the modified rare earth permanent magnetic material according to claim 1, It is characterized in that The x is 10-40%, the y is 0.5-1.5 times of the x, the a is 29-32%, the b is 1-3%, and the c is 0.88-0.96%.

3. The method for preparing the modified rare earth permanent magnetic material according to claim 1, It is characterized in that The d is 4 to 30%.

4. The method for preparing the modified rare earth permanent magnetic material according to any one of claims 1 to 3, It is characterized in that The weight percentage of the alloy is no more than 2wt% based on the total weight of the substrate and the alloy; Preferably, the weight ratio of the alloy to the substrate is (1-15):(900-1000).

5. The method for preparing the modified rare earth permanent magnetic material according to claim 4, It is characterized in that The RE 1 is a combination of La and Ce; preferably, the RE 1 A combination of La and Ce, wherein the weight ratio of the La to the Ce is (0.8-1.2):(2-9.5); The RE 2 is Nd, or a combination of Pr and Nd, or a combination of Pr, Nd and Dy; preferably, the RE 2 is a combination of Pr and Nd; more preferably, the RE 2 A combination of Pr and Nd, wherein the weight ratio of the Pr to the Nd is 1:(2-8); The M 1 is a combination of Co, Al, Cu and Ga, or a combination of Co, Cu, Ga, or a combination of Co, Cu, Al; preferably, the M 1 is a combination of Co, Al, Cu and Ga; more preferably, the M 1 It is a combination of Co, Al, Cu and Ga, and the weight ratio of the Co, the Al, the Cu and the Ga is (0.5-1.5):(0.05-0.5):(0.05-0.5):(0.05-0.5); The RE 3 is Dy, Tb or Pr; preferably, the RE 3 is Dy or Tb; The M 2 is a combination of Co and Cu, or a combination of Co and Al; preferably, the M 2 is a combination of Co and Cu; more preferably, the M 2 It is a combination of Co and Cu, and the weight ratio of the Co to the Cu is (0.5-1.5):(0.05-0.5).

6. The method for preparing the modified rare earth permanent magnetic material according to claim 1, It is characterized in that The solid content of the slurry is 50-90wt%.

7. The method for preparing the modified rare earth permanent magnetic material according to claim 1, It is characterized in that The solvent is selected from one or more of the group consisting of methanol, ethanol, No. 120 gasoline, styrene, perchloroethylene, trichloroethylene, ethylene glycol ether, and triethanolamine, and / or the binder is selected from one or more of the group consisting of epoxy resin, phenolic resin, nitrocellulose, PVC glue, PVB, and PVA.

8. The method for preparing the modified rare earth permanent magnetic material according to claim 1, It is characterized in that The coating is performed by spraying, printing or magnetron sputtering.

9. The method for preparing the modified rare earth permanent magnetic material according to claim 1, It is characterized in that The temperature of the diffusion annealing treatment is 850-950° C., and the time is 3-60 hours.

10. A modified rare earth permanent magnet material, It is characterized in that The modified rare earth permanent magnet material is prepared by the preparation method of the modified rare earth permanent magnet material according to any one of claims 1 to 9.

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