Flexible samarium-iron-nitrogen magnetic sheet and preparation method thereof

Abstract

The invention relates to the technical field of magnetic materials, and particularly discloses a flexible samarium-iron-nitrogen magnetic sheet and a preparation method thereof.The flexible samarium-iron-nitrogen magnetic sheet contains samarium-iron-nitrogen magnetic powder, a dispersing agent, an antioxidant, a binder, a plasticizer and a defoaming agent; wherein the thickness of the flexible samarium-iron-nitrogen magnetic sheet is 30 to 100 [mu] m; the flexible samarium-iron-nitrogen magnetic sheet has high orientation degree, high oxidation resistance and high magnetic performance, meanwhile, the flexible samarium-iron-nitrogen magnetic sheet capable of being oriented is prepared through the method for preparing the flexible samarium-iron-nitrogen magnetic sheet, a novel tape casting process method is provided for preparing the flexible samarium-iron-nitrogen magnetic sheet, and a samarium-iron-nitrogen material has a wider application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic materials, and in particular to a flexible samarium iron nitride magnetic sheet and a preparation method thereof. Background Art

[0002] Since its introduction, SmFeN has been valued by many scientific researchers and has the potential to surpass NdFeB in performance. As the fourth generation of permanent magnet materials, it has excellent physical properties, high Curie temperature, better intrinsic magnetism and better oxidation resistance, good stability and excellent magnetic properties. It has been widely used in nuclear magnetic resonance imaging, microwave communication technology, motors, generators, instruments and other devices and equipment that require permanent magnetic fields. It is one of the research hotspots of rare earth permanent magnet materials at home and abroad. However, with the continuous deepening of research and the expansion of application fields, the current rigid SmFeN block cannot be bent and deformed, and can no longer meet the needs of the market. At the same time, the demand for high-performance flexible sheet magnetic materials in application fields such as high-end furniture and appliances, aerospace, electric vehicles, and wireless charging is increasing.

[0003] The key to the performance of anisotropic SmFeN magnets lies in the orientation of magnetic powder under a magnetic field. Some existing methods for preparing flexible SmFeN do not adopt magnetic field orientation, but adopt magnetic field oriented injection molding technology. This method causes the magnetic powder to be in a low-viscosity medium environment, which increases the rotation resistance of the magnetic powder and greatly reduces its orientation degree. At the same time, the injection molded pellets have poor fluidity, low magnetic powder content, and poor magnetic properties. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the magnetic powder in the flexible SmFeN prepared by the prior art is in a low-viscosity medium environment, which leads to an increase in the rotational resistance of the magnetic powder, greatly reduces its orientation degree, and at the same time, the injection molding pellets have poor fluidity, low magnetic powder content, and poor magnetic properties. Thus, a flexible SmFeN magnetic sheet and a preparation method thereof are provided. The flexible SmFeN magnetic sheet has high orientation degree, high oxidation resistance and high magnetic properties. At the same time, the method for preparing the flexible SmFeN magnetic sheet prepares an oriented flexible SmFeN magnetic sheet, provides a new method of casting process for preparing flexible SmFeN magnetic sheets, and gives the SmFeN material a broader application prospect.

[0005] In order to achieve the above objectives, in the first aspect, the present invention provides a flexible SmFeN magnetic sheet, which contains SmFeN magnetic powder, a dispersant, an antioxidant, a binder, a plasticizer and a defoaming agent; wherein the thickness of the flexible SmFeN magnetic sheet is 30-100 μm.

[0006] Preferably, the weight ratio of the samarium iron nitrogen magnetic powder, dispersant, antioxidant, binder, plasticizer and defoamer is 70:0.5-5:0.2-0.6:2-6:2-6:0.1-0.6.

[0007] Preferably, the samarium iron nitrogen magnetic powder is a flaky powder prepared by Ca reduction nitriding ball milling.

[0008] Preferably, the dispersant is selected from one or more of phosphate amine, triethanolamine, castor oil and NP-10.

[0009] More preferably, the antioxidant is a phosphite.

[0010] More preferably, the binder is selected from one or more of rubber, thermoplastic resin and thermosetting resin.

[0011] More preferably, the binder is selected from one or more of F48 thermosetting phenolic epoxy resin, polyvinyl formal, polymethyl methacrylate and polyvinyl butyral.

[0012] More preferably, the plasticizer is selected from one or more of phthalate plasticizers, terephthalate plasticizers, benzoate plasticizers, benzene polyester plasticizers and polyol ester plasticizers.

[0013] More preferably, the defoaming agent is tributyl phosphate and / or silicone oil.

[0014] In a second aspect, the present invention provides a method for preparing a flexible samarium iron nitride magnetic sheet, the method comprising:

[0015] 1) preparing a tape casting slurry: in the presence of a solvent, samarium iron nitrogen magnetic powder, an antioxidant and a dispersant are mixed, and a first ball milling is performed to obtain a first slurry, a binder and a plasticizer are added to the first slurry, and a second ball milling is performed to obtain a second slurry, and a defoaming agent is added to the second slurry and stirred to obtain a tape casting slurry;

[0016] 2) Tape casting: placing the tape casting slurry in a tape casting machine for tape casting, and applying a parallel magnetic field to orient the mixed slurry after tape casting to obtain a green tape;

[0017] 3) Drying and cutting: drying, curing and cutting the raw tape to obtain the finished product.

[0018] Preferably, in step 1), the weight ratio of the solvent, samarium iron nitrogen magnetic powder, antioxidant, dispersant, binder, plasticizer and defoamer is 15-35:70:0.2-0.6:0.5-5:2-6:2-6:0.1-0.6.

[0019] Preferably, in step 1), the solvent is selected from one or more of ethyl acetate, butanone, toluene, ethanol, butanone and isopropanol.

[0020] Preferably, the samarium iron nitrogen magnetic powder is a flaky powder prepared by Ca reduction nitriding ball milling.

[0021] More preferably, the dispersant is selected from one or more of phosphate amine, triethanolamine, castor oil and NP-10.

[0022] More preferably, the antioxidant is phosphite.

[0023] More preferably, the binder is selected from one or more of rubber, thermoplastic resin and thermosetting resin.

[0024] More preferably, the binder is selected from one or more of F48 thermosetting phenolic epoxy resin, polyvinyl formal, polymethyl methacrylate and polyvinyl butyral.

[0025] More preferably, the plasticizer is selected from one or more of phthalate plasticizers, terephthalate plasticizers, benzoate plasticizers, benzene polyester plasticizers and polyol ester plasticizers.

[0026] More preferably, the defoaming agent is tributyl phosphate and / or silicone oil.

[0027] Preferably, in step 1), the conditions for the first ball milling include: a ball-to-material ratio of 6-14:1, a time of 3-6 hours, a rotation speed of 300-600 rpm, and anhydrous ethanol as the ball milling medium.

[0028] Preferably, the conditions for the second ball milling include: a ball-to-material ratio of 6-14:1, a time of 3-6 hours, a rotation speed of 300-600 rpm, and anhydrous ethanol as the ball milling medium.

[0029] More preferably, the stirring conditions include: time of 0.4-1h, and rotation speed of 100-200rpm.

[0030] Preferably, in step 2), the casting conditions include: temperature of 20-25° C., belt speed of 10-20 mm / s, scraper spacing of 1-2 mm, and stirring rate of 100-150 rpm.

[0031] Preferably, a doctor blade is used to orient the casting slurry during the casting.

[0032] More preferably, the parallel magnetic field is composed of two rectangular NdFeB magnets, which are placed parallel to the casting direction, 4-5 cm apart, and have a magnetic induction intensity of 3000-4000 Gs.

[0033] Preferably, in step 3), the drying conditions include: in a forced air drying oven at a temperature of 25-35° C. for a time of 2-5 h.

[0034] Preferably, in step 3), the curing conditions include: temperature of 130-200° C. and time of 1-3 h.

[0035] In the above technical scheme, the method for preparing flexible samarium iron nitride magnetic sheet of the present invention utilizes a scraper in a casting machine to produce mechanical orientation on the casting slurry, and simultaneously utilizes an external parallel magnetic field to orient the mixed slurry obtained after casting, so as to increase the orientation degree of the samarium iron nitride magnetic powder in the binder, thereby obtaining a flexible samarium iron nitride magnetic sheet with high orientation degree, high oxidation resistance and high magnetic properties.

[0036] At the same time, the present invention provides a new process for preparing flexible samarium iron nitride magnetic sheets, and also expands the application scenarios and application range of samarium iron nitride materials.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 It is a schematic diagram of the casting equipment of the present invention;

[0040] Figure 2 The X-ray diffraction pattern (XRD pattern) of the flexible samarium iron nitrogen magnetic sheet prepared in Example 1 of the present invention;

[0041] Figure 3 This is a scanning electron microscope image (SEM image) of the flexible samarium iron nitride magnetic sheet prepared in Example 1 of the present invention;

[0042] Figure 4 hysteresis loop diagram of the flexible samarium iron nitride magnetic sheets prepared in Examples 1-3 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0043] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0044] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0045] In a first aspect, the present invention provides a flexible SmFeN magnetic sheet, which contains SmFeN magnetic powder, a dispersant, an antioxidant, a binder, a plasticizer and a defoaming agent; wherein the thickness of the flexible SmFeN magnetic sheet is 30-100 μm.

[0046] The flexible samarium iron nitrogen magnetic sheet of the invention has high orientation degree, high oxidation resistance and high magnetic performance.

[0047] In a preferred embodiment of the present invention, in order to improve the flexibility of the flexible SmFeN magnetic sheet, the weight ratio of the SmFeN magnetic powder, dispersant, antioxidant, binder, plasticizer and defoamer is 70:0.5-5:0.2-0.6:2-6:2-6:0.1-0.6.

[0048] In a preferred embodiment of the present invention, in order to better orient the flaky powder along its casting direction during the casting process without being erected and to have a higher degree of adaptability, the samarium iron nitrogen magnetic powder is a flaky powder prepared by Ca reduction nitriding ball milling.

[0049] In a preferred embodiment of the present invention, in order to better achieve uniform dispersion of the samarium iron nitrogen magnetic powder particles in the casting slurry, the dispersant is selected from one or more of phosphate amine, triethanolamine, castor oil and NP-10.

[0050] In a preferred embodiment of the present invention, the antioxidant is a phosphite.

[0051] In a preferred embodiment of the present invention, in order to better connect the samarium iron powder particles, the binder is selected from one or more of rubber, thermoplastic resin and thermosetting resin.

[0052] In a preferred embodiment of the present invention, in order to make the subsequent casting operation highly operable while not hindering the volatilization of the solvent, the binder is selected from one or more of F48 thermosetting phenolic epoxy resin, polyvinyl formal, polymethyl methacrylate and polyvinyl butyral.

[0053] In a preferred embodiment of the present invention, in order to obtain a highly flexible samarium iron nitrogen magnetic sheet, the plasticizer is selected from one or more of phthalate plasticizers, terephthalate plasticizers, benzoate plasticizers, polybenzoate plasticizers and polyol ester plasticizers.

[0054] In a preferred embodiment of the present invention, in order to better remove the bubbles generated after ball milling, the defoaming agent is tributyl phosphate and / or silicone oil.

[0055] In a second aspect, the present invention provides a method for preparing a flexible samarium iron nitride magnetic sheet, the method comprising:

[0056] 1) preparing a tape casting slurry: in the presence of a solvent, samarium iron nitrogen magnetic powder, an antioxidant and a dispersant are mixed, and a first ball milling is performed to obtain a first slurry, a binder and a plasticizer are added to the first slurry, and a second ball milling is performed to obtain a second slurry, and a defoaming agent is added to the second slurry and stirred to obtain a tape casting slurry;

[0057] 2) Tape casting: placing the tape casting slurry in a tape casting machine for tape casting, and applying a parallel magnetic field to orient the mixed slurry after tape casting to obtain a green tape;

[0058] 3) Drying and cutting: drying, curing and cutting the raw tape to obtain the finished product.

[0059] The method for preparing a flexible samarium iron nitrogen magnetic sheet of the present invention utilizes a scraper in a tape casting machine to produce mechanical orientation for the tape casting slurry, and simultaneously utilizes an external parallel magnetic field to orient the mixed slurry obtained after tape casting, so as to improve the orientation degree of the samarium iron nitrogen magnetic powder in the binder, thereby obtaining a flexible samarium iron nitrogen magnetic sheet with high orientation degree, high oxidation resistance and high magnetic properties. At the same time, the present invention provides a new process for preparing a flexible samarium iron nitrogen magnetic sheet, and also expands the application scenarios and application range of samarium iron nitrogen materials.

[0060] In a preferred embodiment of the present invention, in order to better stabilize the slurry, inhibit particle sedimentation and ensure its flexibility, in step 1), the weight ratio of the solvent, samarium iron nitrogen magnetic powder, antioxidant, dispersant, binder, plasticizer and defoamer is 15-35:70:0.2-0.6:0.5-5:2-6:2-6:0.1-0.6.

[0061] In a preferred embodiment of the present invention, in order to better provide viscosity to the samarium iron nitrogen slurry and fully disperse the samarium iron nitrogen magnetic powder while ensuring the chemical stability in the slurry, in step 1), the solvent is selected from one or more of ethyl acetate, butanone, toluene, ethanol, butanone and isopropanol.

[0062] In a preferred embodiment of the present invention, in order to better orient the flaky powder along its casting direction during the casting process without being erected and to have a higher degree of adaptability, the samarium iron nitrogen magnetic powder is a flaky powder prepared by Ca reduction nitriding ball milling.

[0063] In a preferred embodiment of the present invention, in order to better achieve uniform dispersion of the samarium iron nitrogen magnetic powder particles in the casting slurry, the dispersant is selected from one or more of phosphate amine, triethanolamine, castor oil and NP-10.

[0064] In a preferred embodiment of the present invention, the antioxidant is a phosphite.

[0065] In a preferred embodiment of the present invention, in order to better connect the samarium iron powder particles, the binder is selected from one or more of rubber, thermoplastic resin and thermosetting resin.

[0066] In a preferred embodiment of the present invention, in order to make the subsequent casting operation highly operable while not hindering the volatilization of the solvent, the binder is selected from one or more of F48 thermosetting phenolic epoxy resin, polyvinyl formal, polymethyl methacrylate and polyvinyl butyral.

[0067] In a preferred embodiment of the present invention, in order to better obtain a highly flexible samarium iron nitrogen magnetic sheet, the plasticizer is selected from one or more of phthalate plasticizers, terephthalate plasticizers, benzoate plasticizers, polybenzoate plasticizers and polyol ester plasticizers.

[0068] In a preferred embodiment of the present invention, in order to better remove the bubbles generated after ball milling, the defoaming agent is tributyl phosphate and / or silicone oil.

[0069] In a preferred embodiment of the present invention, in order to better mix the powder with the antioxidant and the dispersant, in step 1), the conditions of the first ball milling include: a ball-to-material ratio of 6-14:1, a time of 3-6 hours, a rotation speed of 300-600 rpm, and anhydrous ethanol as the ball milling medium.

[0070] In a preferred embodiment of the present invention, in order to better mix the binder and plasticizer with the slurry after the first ball milling, the conditions of the second ball milling include: a ball-to-material ratio of 6-14:1, a time of 3-6h, a rotation speed of 300-600rpm, and anhydrous ethanol as the ball milling medium.

[0071] In a preferred embodiment of the present invention, in order to better mix the second ball-milled slurry with the defoamer, the stirring conditions include: a time of 0.4-1h and a rotation speed of 100-200rpm.

[0072] In a preferred embodiment of the present invention, in order to better maintain the dispersion uniformity of the final slurry, in step 2), the casting conditions include: temperature of 20-25°C, belt speed of 10-20 mm / s, scraper spacing of 1-2 mm, and stirring rate of 100-150 rpm.

[0073] In a preferred embodiment of the present invention, in order to realize mechanical orientation and achieve a high degree of orientation, a doctor blade is used to orient the casting slurry during the casting.

[0074] In a preferred embodiment of the present invention, in order to improve the magnetic properties of the flexible magnetic sheet and improve the uniformity of the magnetic powder orientation during the casting process, the parallel magnetic field is composed of two rectangular NdFeB magnets, which are placed parallel to the casting direction, 4-5 cm apart, and have a magnetic induction intensity of 3000-4000Gs.

[0075] In a preferred embodiment of the present invention, in order to obtain better flatness during drying, in step 3), the drying conditions include: in a blast drying oven, the temperature is 25-35° C., and the time is 2-5 hours.

[0076] In a preferred embodiment of the present invention, in order to better remove the bubbles generated after ball milling, in step 3), the curing conditions include: temperature of 130-200° C. and time of 1-3 h.

[0077] The present invention will be described in detail below through examples. In the following examples, the drugs and pharmaceutical agents are all conventional commercial products.

[0078] Example 1

[0079] (1) Ingredients: 70 parts of samarium iron nitrogen magnetic powder, 20 parts of solvent (the mass ratio of ethanol to acetone is 2:3), 2 parts of NP-10, 0.6 parts of phosphite, 4 parts of polyvinyl butyral (PVB), 3 parts of dibutyl phthalate (S160) and 0.4 parts of tributyl phosphate were weighed according to weight parts;

[0080] (2) preparing a tape casting slurry: placing the samarium iron nitrogen magnetic powder, solvent, NP-10 and phosphite weighed in step (1) in a ball mill (ball to material ratio of 9:1), ball milling at 400 rpm for 4 h in a planetary ball mill, then adding the PVB and S160 weighed in step (1) and ball milling at 400 rpm for 4 h, finally adding the tributyl phosphate weighed in step (1) into the slurry twice and stirring to prepare a tape casting slurry;

[0081] (3) Tape casting: The tape slurry prepared in step (2) is cast through a tape casting machine to obtain a green tape, during which the casting temperature is maintained at 35° C., the tape speed is 10 mm / s, and the scraper spacing is 1.4 mm. When entering the magnetic field formed by two rectangular NdFeB magnets, the tape speed is 20 mm / s. The mechanical orientation of the scraper and the magnetic field orientation are used to achieve a high degree of orientation of the material. At the same time, the slurry is slowly stirred during the casting process;

[0082] (4) Drying and cutting: The raw tape obtained in step (3) is placed in a 30°C forced air drying oven for 5 hours to prevent the film from wrinkling, and then placed in a 180°C forced air drying oven for curing for 3 hours, and cut into shape to obtain a flexible samarium iron nitride magnetic sheet, recorded as B1.

[0083] Example 2

[0084] The method of Example 1 was followed, except that the number of parts of the binder polyvinyl butyral was replaced from 4 parts to 5 parts, to obtain a flexible samarium iron nitride magnetic sheet, which was recorded as B2.

[0085] Example 3

[0086] The method of Example 1 was followed, except that the number of parts of the binder polyvinyl butyral was replaced by 6 parts from 4 parts, to obtain a flexible samarium iron nitrogen magnetic sheet, which was recorded as B3.

[0087] Comparative Example 1

[0088] The method of Example 1 is followed, except that the slurry after casting does not enter the magnetic field formed by two rectangular NdFeB magnets, to obtain a flexible SmFeN magnetic sheet, which is recorded as D1.

[0089] Test Example 1

[0090] The results of X-ray diffractometer (XRD) analysis of the flexible samarium iron nitrogen magnetic sheet of Example 1 are shown in FIG. Figure 2 .

[0091] Depend on Figure 2 It can be seen from the XRD pattern of the flexible SmFeN magnetic sheet of Example 1 that the flexible SmFeN magnetic sheet prepared in Example 1 of the present invention has high purity, and no Sm-rich image and α-Fe phase exist.

[0092] Test Example 2

[0093] The morphology of the flexible SmFeN magnetic sheet of Example 1 was analyzed using a scanning electron microscope. Figure 3 .

[0094] Depend on Figure 3 It can be seen from the SEM image of the flexible SmFeN magnetic sheet of Example 1 that the flexible SmFeN magnetic sheet prepared in Example 1 of the present invention has a hexagonal structure.

[0095] Test Example 3

[0096] The hysteresis loop test of the flexible samarium iron nitride magnetic sheets prepared in Examples 1-3 and Comparative Example 1 was performed using a vibrating sample magnetometer (VSM). The specific test results are shown in Tables 1 and Figure 4 As shown:

[0097] Table 1

[0098]

[0099] From Table 1 and Figure 4 It can be seen from the data that the present invention obtains a flexible SmFeN magnetic sheet with high coercivity by using a tape casting process to perform dual orientation on the SmFeN magnetic sheet.

[0100] In summary, the method for preparing flexible samarium iron nitride magnetic sheets of the present invention successfully solves the problems of poor fluidity of samarium iron nitride magnetic powder particles, low viscous medium environment and poor oxidation resistance through a casting process. On the basis of solving the fluidity and viscous medium problems, a hexagonal flexible samarium iron nitride magnetic sheet with high magnetic properties and high corrosion resistance is obtained by utilizing dual orientation, namely, mechanical orientation of a scraper and magnetic field orientation achieved by a magnet.

[0101] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0102] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0103] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A flexible samarium iron nitride magnetic sheet, characterized in that: The flexible SmFeN magnetic sheet contains SmFeN magnetic powder, dispersant, antioxidant, binder, plasticizer and defoamer; wherein, The thickness of the flexible SmFeN magnetic sheet is 30-100 μm.

2. The flexible SmFeN magnetic sheet according to claim 1, characterized in that: The weight ratio of the samarium iron nitrogen magnetic powder, dispersant, antioxidant, binder, plasticizer and defoamer is 70:0.5-5:0.2-0.6:2-6:2-6:0.1-0.

6.

3. The flexible SmFeN magnetic sheet according to claim 1 or 2, characterized in that: The samarium iron nitrogen magnetic powder is a flaky powder prepared by Ca reduction nitriding ball milling; Preferably, the dispersant is selected from one or more of phosphate amine, triethanolamine, castor oil and NP-10; More preferably, the antioxidant is a phosphite; Further preferably, the binder is selected from one or more of rubber, thermoplastic resin and thermosetting resin; More preferably, the binder is selected from one or more of F48 thermosetting phenolic epoxy resin, polyvinyl formal, polymethyl methacrylate and polyvinyl butyral; More preferably, the plasticizer is selected from one or more of phthalate plasticizers, terephthalate plasticizers, benzoate plasticizers, benzene polyester plasticizers and polyol ester plasticizers; More preferably, the defoaming agent is tributyl phosphate and / or silicone oil.

4. A method for preparing a flexible samarium iron nitride magnetic sheet, characterized in that: The method comprises: 1) preparing a tape casting slurry: in the presence of a solvent, samarium iron nitrogen magnetic powder, an antioxidant and a dispersant are mixed, and a first ball milling is performed to obtain a first slurry, a binder and a plasticizer are added to the first slurry, and a second ball milling is performed to obtain a second slurry, and a defoaming agent is added to the second slurry and stirred to obtain a tape casting slurry; 2) Tape casting: placing the tape casting slurry in a tape casting machine for tape casting, and applying a parallel magnetic field to orient the mixed slurry after tape casting to obtain a green tape; 3) Drying and cutting: drying, curing and cutting the raw tape to obtain the finished product.

5. The method according to claim 4, characterized in that In step 1), the weight ratio of the solvent, samarium iron nitrogen magnetic powder, antioxidant, dispersant, binder, plasticizer and defoamer is 15-35:70:0.2-0.6:0.5-5:2-6:2-6:0.1-0.

6.

6. The method according to claim 4 or 5, characterized in that: In step 1), the solvent is selected from one or more of ethyl acetate, butanone, toluene, ethanol, butanone and isopropanol; Preferably, the samarium iron nitrogen magnetic powder is a flaky powder prepared by Ca reduction nitriding ball milling; More preferably, the dispersant is selected from one or more of phosphate amine, triethanolamine, castor oil and NP-10; Further preferably, the antioxidant is a phosphite; More preferably, the binder is selected from one or more of rubber, thermoplastic resin and thermosetting resin; More preferably, the binder is selected from one or more of F48 thermosetting phenolic epoxy resin, polyvinyl formal, polymethyl methacrylate and polyvinyl butyral; More preferably, the plasticizer is selected from one or more of phthalate plasticizers, terephthalate plasticizers, benzoate plasticizers, benzene polyester plasticizers and polyol ester plasticizers; More preferably, the defoaming agent is tributyl phosphate and / or silicone oil.

7. The method according to any one of claims 4 to 6, characterized in that: In step 1), the conditions of the first ball milling include: a ball-to-material ratio of 6-14:1, a time of 3-6 hours, a rotation speed of 300-600 rpm, and anhydrous ethanol as the ball milling medium; Preferably, the conditions of the second ball milling include: a ball-to-material ratio of 6-14:1, a time of 3-6 hours, a rotation speed of 300-600 rpm, and anhydrous ethanol as the ball milling medium; More preferably, the stirring conditions include: time of 0.4-1h, and rotation speed of 100-200rpm.

8. The method according to any one of claims 4 to 7, characterized in that: In step 2), the casting conditions include: temperature of 20-25° C., belt speed of 10-20 mm / s, scraper spacing of 1-2 mm, and stirring rate of 100-150 rpm; Preferably, a scraper is used to orient the casting slurry during the casting; More preferably, the parallel magnetic field is composed of two rectangular NdFeB magnets, which are placed parallel to the casting direction, 4-5 cm apart, and have a magnetic induction intensity of 3000-4000 Gs.

9. The method according to any one of claims 4 to 8, characterized in that: In step 3), the drying conditions include: in a forced air drying oven, the temperature is 25-35° C., and the time is 2-5 hours.

10. The method according to any one of claims 4 to 9, characterized in that: In step 3), the curing conditions include: temperature of 130-200° C. and time of 1-3 hours.

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