A modified manganese tetroxide and its application in soft magnets

Abstract

This invention relates to the field of ferrite magnetic materials technology, specifically to a modified manganese tetroxide and its application in soft magnets. The invention provides a modified manganese tetroxide and its application in soft magnets, which utilizes electrospinning technology with polyvinylpyrrolidone as a fiber template to form a composite nanofiber material with zinc ferrite as the inner layer and manganese tetroxide and cobalt tetraoxide ferrite as the outer layer, i.e., a modified manganese tetroxide fiber material. Using this as the fiber skeleton, modified polysiloxane and silicone resin are used as encapsulating materials to construct a three-dimensional anisotropic soft magnetic composite material. This solves the contradictory problems of high eddy current loss and difficulty in simultaneously achieving saturation magnetic induction intensity and high-frequency permeability in traditional soft magnetic materials at high frequencies.

Description

Technical Field

[0001] This invention relates to the field of ferrite magnetic materials technology, specifically to a modified manganese tetroxide and its application in soft magnets. Background Technology

[0002] Manganese-zinc ferrite is the most widely used soft magnetic material in the electronics industry. However, with the development of 5G communication, new energy vehicles, and high-efficiency fast charging technology, the operating frequency of electronic devices is increasing. As the frequency of use increases, the eddy current loss of soft magnetic materials increases dramatically. To improve the performance of soft magnetic materials under high-frequency conditions, the most common method is to mix magnetic powder with insulating resin and press it into shape, as illustrated in patent CN103151134B, "Silicone Resin-Ferrite Composite Coated Soft Magnetic Powder Core and its Preparation Method." This method uses silicone resin as the insulating coating material, and involves surface modification and coupling treatment of soft magnetic metal particles, forming a composite insulating coating surrounding each soft magnetic metal particle, pressing, and high-temperature heat treatment at 300-650℃. While this method effectively suppresses eddy currents, the large amount of non-magnetic resin severely reduces the material's effective permeability and saturation magnetic induction. Therefore, a soft magnetic material is needed that can effectively suppress eddy current losses caused by high frequencies, while maintaining or even increasing its effective permeability and saturation magnetic induction. Summary of the Invention

[0003] The purpose of this invention is to provide a modified manganese tetroxide and its application in soft magnets. It uses electrospinning technology with polyvinylpyrrolidone as a fiber template to form a composite nanofiber material with zinc ferrite as the inner layer and manganese tetroxide and cobalt tetraoxide diferrate as the outer layer, namely the modified manganese tetroxide fiber material. Using this as the fiber skeleton, modified polysiloxane and silicone resin are used as encapsulating materials to construct a three-dimensional anisotropic soft magnetic composite material. This solves the contradiction between high eddy current loss and difficulty in achieving both saturation magnetic induction intensity and high-frequency permeability in traditional soft magnetic materials at high frequencies.

[0004] The objective of this invention can be achieved through the following technical solution: an application of modified manganese tetroxide in soft magnets, comprising the following steps: Step S1: Weigh the following raw materials in parts by weight: 35-40 parts ferric oxide, 25-30 parts manganese oxide, 10-15 parts zinc oxide, 8-10 parts modified manganese tetroxide fiber material, 2.5-4 parts silicone resin, 0.8-1 parts modified polysiloxane, and 50-60 parts xylene;

[0005] Step S2: Mix silicone resin, modified polysiloxane and xylene, then add ferric oxide, manganese oxide, zinc oxide and modified manganese tetroxide fiber material and continue mixing. Add to mold, vacuum dry at 150℃ under vertical orientation magnetic field, press at 600MPa, then heat to 600℃ under argon protection at a heating rate of 1℃ / min and hold for 2h, then heat to 1300℃ at a heating rate of 5℃ / min and hold for 6h to obtain composite soft magnetic material;

[0006] Furthermore, the ferric oxide, manganese oxide, and zinc oxide are from Wuhan Jiyesheng Chemical Co., Ltd.; the silicone resin is from Hubei Longsheng Sihai New Material Co., Ltd., and the model is DC805.

[0007] The modified manganese tetroxide fiber material is prepared by the following steps:

[0008] Step A1: Mix ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, and N,N-dimethylformamide. Stir at 200-300 rpm and 35°C for 3.5-4 hours. Then add polyvinylpyrrolidone and stir at room temperature for 24 hours to obtain a spinning solution. Transfer the spinning solution into the syringe of an electrospinning device. Perform electrospinning with the needle 15 cm away from the collection device, a spinning flow rate of 0.3 mL / h, and a voltage of 15 kV to obtain precursor fibers.

[0009] Furthermore, in step A1: the ratio of ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, N,N-dimethylformamide and polyvinylpyrrolidone is 8-8.1g: 2.9-3g: 50-55mL: 50-55mL: 28-30g;

[0010] Furthermore, the polyvinylpyrrolidone is sourced from Jinan Zhengkang Chemical Co., Ltd., and its model number is K30.

[0011] Step A2: Mix sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol and deionized water. Stir for 15-20 minutes in an air atmosphere at a stirring speed of 300-400 rpm and a temperature of 60°C. Then add the precursor fiber and ultrasonically disperse for 8-10 minutes. Add manganese sulfate solution and continue the reaction for 5-6 hours. Centrifuge, filter, wash and dry to obtain the composite precursor fiber.

[0012] Furthermore, in step A2: the ratio of sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol, deionized water, precursor fiber, and manganese sulfate solution is 2.8-3g: 1-1.2g: 1-1.2g: 90-100mL: 280-300mL: 1.6-1.7g: 9.5-10mL, and the mass concentration of manganese sulfate solution is 0.1g / mL;

[0013] Step A3: Mix ferric nitrate nonahydrate, cobalt nitrate hexahydrate, and deionized water, stir, add sodium hydroxide solution, adjust the pH to 10, then add composite precursor fiber, react for 1.5-2 hours at a stirring rate of 120-150 rpm and a temperature of 80℃, centrifuge, filter, wash, and dry to obtain secondary composite precursor fiber, transfer the secondary composite precursor fiber to a tube furnace, calcine at 600℃ for 2 hours in an air atmosphere with a heating rate of 3℃ / min, cool, and obtain modified manganese tetroxide fiber material;

[0014] Furthermore, in step A3: the ratio of ferric nitrate nonahydrate, cobalt nitrate hexahydrate, deionized water, and composite precursor fiber is 4-4.1g: 1.45-1.5g: 80-90mL: 1-1.1g, and the molar concentration of sodium hydroxide solution is 5mol / L.

[0015] Furthermore, during the reaction process, polyvinylpyrrolidone is used as a viscosity agent, and ferric nitrate nonahydrate and zinc nitrate hexahydrate are used as iron and zinc sources, respectively. Precursor fibers are prepared by electrospinning. Manganese sulfate is used as a manganese source, and hexadecyltrimethylammonium bromide and polyacrylic acid are used as auxiliaries to generate manganese tetroxide on the fiber surface, thus obtaining composite precursor fibers. Then, through chemical coprecipitation, ferric nitrate nonahydrate and cobalt nitrate hexahydrate are used as iron and cobalt sources, respectively, to generate cobalt tetraoxonide on the surface of the composite precursor fibers, thus obtaining secondary composite precursor fibers. After calcination, because polyvinylpyrrolidone is used as a fiber template, a composite nanofiber material is formed with zinc ferrate as the inner layer and manganese tetroxide and cobalt tetraoxonide as the outer layer, namely, modified manganese tetroxide fiber material.

[0016] The modified polysiloxane is prepared by the following steps:

[0017] Step B1: Boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane and diethylene glycol dimethyl ether are mixed and reacted under nitrogen protection at a stirring rate of 120-150 rpm and a temperature of 90℃ for 1.5-2 h. The temperature is then raised to 110℃ and the reaction is continued for 40-60 min. Hydroquinone and stannous chloride are added while stirring, and the temperature is raised to 150℃ and the reaction is continued for 4-6 h. The mixture is then evaporated under reduced pressure and dried to obtain the aminosiloxane prepolymer.

[0018] Furthermore, in step B1, the ratio of boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane, diethylene glycol dimethyl ether, hydroquinone, and stannous chloride is 1.24-1.25g: 0.48-0.5g: 7.92-7.95g: 15-20mL: 0.51-0.54g: 0.01-0.012g.

[0019] Step B2: Mix nickel acetylacetonate, aminosiloxane prepolymer and tetrahydrofuran, and react at room temperature with a stirring rate of 100-120 rpm for 3-5 h. Then add n-butyl ester and phenolic resin, and continue to react for 1.5-2 h. Dry under reduced pressure to obtain modified polysiloxane.

[0020] Furthermore, in step B2: the ratio of nickel acetylacetonate, aminosiloxane prepolymer, tetrahydrofuran, n-butyl ester and phenolic resin is 0.24-0.25g: 1.5-1.8g: 15-20mL: 0.12-0.15g: 1.2-1.3g.

[0021] Furthermore, during the reaction, boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, and phenyltrimethoxysilane are used as monomers to form a long-chain structure of borosilicate with N-aminoethyl-3-aminopropyl side chain through hydrolysis and condensation. Hydroquinone and stannous chloride are added to continue the reaction, introducing phenolic hydroxyl structures to obtain an aminosiloxane prepolymer. Then, through the coordination complexation between the phenolic hydroxyl groups in the aminosiloxane prepolymer and N-aminoethyl-3-aminopropyl and nickel acetylacetonate, it is introduced to obtain a modified polysiloxane containing rare earth elements.

[0022] The beneficial effects of this invention: This invention discloses a modified manganese tetroxide and its application in soft magnets. Through electrospinning technology, using polyvinylpyrrolidone as a fiber template, a composite nanofiber material is formed with zinc ferrite as the inner layer and manganese tetroxide and cobalt tetraoxide diferrate as the outer layer, namely the modified manganese tetroxide fiber material. Using this as the fiber skeleton, modified polysiloxane and silicone resin are used as encapsulating materials to construct a three-dimensional anisotropic soft magnetic composite material, thereby solving the contradictory problems of high eddy current loss and difficulty in achieving both saturation magnetic induction intensity and high-frequency magnetic permeability in traditional soft magnetic materials at high frequencies.

[0023] In the preparation process of its soft magnetic material, a vertical orientation magnetic field is used as a guiding magnetic field to cause the added modified manganese tetroxide fiber material to form a three-dimensional anisotropic skeleton structure. At the same time, the modified manganese tetroxide fiber material, as a magnetic fiber with a multi-layer structure, causes the flow direction of eddy currents in the soft magnetic material to change in a high-frequency environment, that is, to flow along the fiber orientation direction. Moreover, it has a synergistic effect with the encapsulating agent, which greatly improves the internal resistance of the soft magnetic material, thereby fundamentally suppressing the generation of high-frequency eddy current loss. By adding modified polysiloxane boron dopants, nickel and boron elements are introduced at the molecular scale. And because it is compounded with silicone resin, it decomposes into beneficial phases after sintering. Therefore, compared with traditional organic insulating encapsulating materials, the dilution effect on saturation magnetic induction intensity is minimal, achieving a unity of high saturation magnetic induction intensity and low high-frequency eddy current loss. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The polyacrylic acid is from Jiangsu Maikai Biotechnology Co., Ltd., and its model number is PAA 980.

[0026] Example 1 An application of modified manganese tetroxide in soft magnets, comprising the following steps: Step S1: Weigh the following raw materials in parts by weight: 35 parts ferric oxide, 25 parts manganese oxide, 10 parts zinc oxide, 8 parts modified manganese tetroxide fiber material, 2.5 parts silicone resin, 0.8 parts modified polysiloxane and 50 parts xylene;

[0027] Step S2: Mix silicone resin, modified polysiloxane and xylene, then add ferric oxide, manganese oxide, zinc oxide and modified manganese tetroxide fiber material and continue mixing. Add to mold, vacuum dry at 150℃ under vertical orientation magnetic field, press at 600MPa, then heat to 600℃ under argon protection at a heating rate of 1℃ / min and hold for 2h, then heat to 1300℃ at a heating rate of 5℃ / min and hold for 6h to obtain composite soft magnetic material;

[0028] Furthermore, the ferric oxide, manganese oxide, and zinc oxide are from Wuhan Jiyesheng Chemical Co., Ltd.; the silicone resin is from Hubei Longsheng Sihai New Material Co., Ltd., and the model is DC805.

[0029] The modified manganese tetroxide fiber material is prepared by the following steps:

[0030] Step A1: Ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, and N,N-dimethylformamide were mixed and stirred for 3.5 h at a stirring rate of 200 rpm and a temperature of 35 °C. Then, polyvinylpyrrolidone was added and stirred for 24 h at room temperature to obtain a spinning solution. The spinning solution was transferred into the syringe of an electrospinning device. Electrospinning was performed with the needle 15 cm away from the collection device, the spinning flow rate 0.3 mL / h, and the voltage 15 kV to obtain precursor fibers.

[0031] Furthermore, in step A1, the ratio of ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, N,N-dimethylformamide, and polyvinylpyrrolidone is 8g:2.9g:50mL:50mL:28g;

[0032] Furthermore, the polyvinylpyrrolidone is sourced from Jinan Zhengkang Chemical Co., Ltd., and its model number is K30.

[0033] Step A2: Sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol and deionized water are mixed and stirred for 15 minutes in an air atmosphere at a stirring speed of 300 rpm and a temperature of 60°C. Then the precursor fiber is added and ultrasonically dispersed for 8 minutes. Then manganese sulfate solution is added and the reaction is continued for 5 hours. After centrifugation, filtration, washing and drying, the composite precursor fiber is obtained.

[0034] Furthermore, in step A2: the ratio of sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol, deionized water, precursor fiber, and manganese sulfate solution is 2.8g:1g:1g:90mL:280mL:1.6g:9.5mL, and the mass concentration of manganese sulfate solution is 0.1g / mL;

[0035] Furthermore, the polyacrylic acid is sourced from Jiangsu Maikai Biotechnology Co., Ltd., and its model number is PAA 980.

[0036] Step A3: Mix ferric nitrate nonahydrate, cobalt nitrate hexahydrate, and deionized water, stir, add sodium hydroxide solution, adjust the pH to 10, then add composite precursor fiber, react for 1.5 h at a stirring rate of 120 rpm and a temperature of 80℃, centrifuge, filter, wash, and dry to obtain secondary composite precursor fiber, transfer the secondary composite precursor fiber to a tube furnace, calcine at 600℃ in an air atmosphere for 2 h at a heating rate of 3℃ / min, cool, and obtain modified manganese tetroxide fiber material;

[0037] Furthermore, in step A3: the ratio of ferric nitrate nonahydrate, cobalt nitrate hexahydrate, deionized water, and composite precursor fiber is 4g:1.45g:80mL:1g, and the molar concentration of sodium hydroxide solution is 5mol / L.

[0038] The modified polysiloxane is prepared by the following steps:

[0039] Step B1: Boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane and diethylene glycol dimethyl ether were mixed and reacted at 90°C for 1.5 h under nitrogen protection with a stirring rate of 150 rpm. The temperature was then raised to 110°C and the reaction was continued for 60 min. Hydroquinone and stannous chloride were added while stirring, and the temperature was raised to 150°C and the reaction was continued for 4 h. The mixture was then evaporated under reduced pressure and dried to obtain the aminosiloxane prepolymer.

[0040] Furthermore, in step B1, the ratio of boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane, diethylene glycol dimethyl ether, hydroquinone, and stannous chloride is 1.25g:0.48g:7.92g:15mL:0.54g:0.01g.

[0041] Step B2: Nickel acetylacetonate, aminosiloxane prepolymer and tetrahydrofuran are mixed and reacted at room temperature with a stirring rate of 120 rpm for 3 h. Then n-butyl ester and phenolic resin are added and the reaction is continued for 1.5 h. The mixture is then evaporated under reduced pressure and dried to obtain modified polysiloxane.

[0042] Furthermore, in step B2: the ratio of nickel acetylacetonate, aminosiloxane prepolymer, tetrahydrofuran, n-butyl ester and phenolic resin is 0.25g:1.8g:15mL:0.15g:1.2g.

[0043] Example 2 An application of modified manganese tetroxide in soft magnets, comprising the following steps: Step S1: Weigh the following raw materials by weight: 40 parts ferric oxide, 25 parts manganese oxide, 15 parts zinc oxide, 8 parts modified manganese tetroxide fiber material, 4 parts silicone resin, 0.8 parts modified polysiloxane and 60 parts xylene;

[0044] Step S2: Mix silicone resin, modified polysiloxane and xylene, then add ferric oxide, manganese oxide, zinc oxide and modified manganese tetroxide fiber material and continue mixing. Add to mold, vacuum dry at 150℃ under vertical orientation magnetic field, press at 600MPa, then heat to 600℃ under argon protection at a heating rate of 1℃ / min and hold for 2h, then heat to 1300℃ at a heating rate of 5℃ / min and hold for 6h to obtain composite soft magnetic material;

[0045] Furthermore, the ferric oxide, manganese oxide, and zinc oxide are from Wuhan Jiyesheng Chemical Co., Ltd.; the silicone resin is from Hubei Longsheng Sihai New Material Co., Ltd., and the model is DC805.

[0046] The modified manganese tetroxide fiber material is prepared by the following steps:

[0047] Step A1: Ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, and N,N-dimethylformamide were mixed and stirred for 3.5 h at a stirring rate of 300 rpm and a temperature of 35 °C. Then, polyvinylpyrrolidone was added and stirred for 24 h at room temperature to obtain a spinning solution. The spinning solution was transferred into the syringe of an electrospinning device. Electrospinning was performed with the needle 15 cm away from the collection device, the spinning flow rate 0.3 mL / h, and the voltage 15 kV to obtain precursor fibers.

[0048] Furthermore, in step A1: the ratio of ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, N,N-dimethylformamide and polyvinylpyrrolidone is 8g:2.9g:55mL:50mL:28g;

[0049] Furthermore, the polyvinylpyrrolidone is sourced from Jinan Zhengkang Chemical Co., Ltd., and its model number is K30.

[0050] Step A2: Sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol and deionized water are mixed and stirred for 15 min in an air atmosphere at a stirring speed of 400 rpm and a temperature of 60°C. Then the precursor fiber is added and ultrasonically dispersed for 10 min. Then manganese sulfate solution is added and the reaction is continued for 5 h. After centrifugation, filtration, washing and drying, the composite precursor fiber is obtained.

[0051] Furthermore, in step A2: the ratio of sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol, deionized water, precursor fiber, and manganese sulfate solution is 3g:1g:1.2g:90mL:300mL:1.6g:10mL, and the mass concentration of manganese sulfate solution is 0.1g / mL;

[0052] Furthermore, the polyacrylic acid is sourced from Jiangsu Maikai Biotechnology Co., Ltd., and its model number is PAA 980.

[0053] Step A3: Mix ferric nitrate nonahydrate, cobalt nitrate hexahydrate, and deionized water, stir, add sodium hydroxide solution, adjust the pH to 10, then add composite precursor fiber, react for 2 hours at a stirring rate of 120 rpm and a temperature of 80℃, centrifuge, filter, wash, and dry to obtain secondary composite precursor fiber, transfer the secondary composite precursor fiber to a tube furnace, calcine for 2 hours at a temperature of 600℃ in an air atmosphere with a heating rate of 3℃ / min, cool, and obtain modified manganese tetroxide fiber material;

[0054] Furthermore, in step A3: the ratio of ferric nitrate nonahydrate, cobalt nitrate hexahydrate, deionized water, and composite precursor fiber is 4g:1.5g:80mL:1g, and the molar concentration of sodium hydroxide solution is 5mol / L.

[0055] The modified polysiloxane is prepared by the following steps:

[0056] Step B1: Boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane and diethylene glycol dimethyl ether were mixed and reacted at 90°C for 1.5 h under nitrogen protection with a stirring rate of 120 rpm. The temperature was then raised to 110°C and the reaction was continued for 40 min. Hydroquinone and stannous chloride were added while stirring, and the temperature was raised to 150°C and the reaction was continued for 4 h. The mixture was then evaporated under reduced pressure and dried to obtain the aminosiloxane prepolymer.

[0057] Furthermore, in step B1, the ratio of boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane, diethylene glycol dimethyl ether, hydroquinone, and stannous chloride is 1.24g:0.48g:7.92g:15mL:0.514g:0.01g.

[0058] Step B2: Nickel acetylacetone, aminosiloxane prepolymer and tetrahydrofuran are mixed and reacted at room temperature with a stirring rate of 100 rpm for 3 h. Then n-butyl ester and phenolic resin are added and the reaction is continued for 1.5 h. The mixture is then evaporated under reduced pressure and dried to obtain modified polysiloxane.

[0059] Furthermore, in step B2, the ratio of nickel acetylacetonate, aminosiloxane prepolymer, tetrahydrofuran, n-butyl ester, and phenolic resin is 0.24g:1.5g:15mL:0.12g:1.2g.

[0060] Example 3 An application of modified manganese tetroxide in soft magnets, comprising the following steps: Step S1: Weigh the following raw materials by weight: 40 parts ferric oxide, 30 parts manganese oxide, 15 parts zinc oxide, 10 parts modified manganese tetroxide fiber material, 4 parts silicone resin, 1 part modified polysiloxane and 60 parts xylene.

[0061] Step S2: Mix silicone resin, modified polysiloxane and xylene, then add ferric oxide, manganese oxide, zinc oxide and modified manganese tetroxide fiber material and continue mixing. Add to mold, vacuum dry at 150℃ under vertical orientation magnetic field, press at 600MPa, then heat to 600℃ under argon protection at a heating rate of 1℃ / min and hold for 2h, then heat to 1300℃ at a heating rate of 5℃ / min and hold for 6h to obtain composite soft magnetic material;

[0062] Furthermore, the ferric oxide, manganese oxide, and zinc oxide are from Wuhan Jiyesheng Chemical Co., Ltd.; the silicone resin is from Hubei Longsheng Sihai New Material Co., Ltd., and the model is DC805.

[0063] The modified manganese tetroxide fiber material is prepared by the following steps:

[0064] Step A1: Ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, and N,N-dimethylformamide were mixed and stirred for 4 hours at a stirring rate of 300 rpm and a temperature of 35°C. Then, polyvinylpyrrolidone was added and stirred for 24 hours at room temperature to obtain a spinning solution. The spinning solution was transferred into the syringe of an electrospinning device. Electrospinning was performed with the needle 15 cm away from the collection device, the spinning flow rate 0.3 mL / h, and the voltage 15 kV to obtain precursor fibers.

[0065] Furthermore, in step A1: the ratio of ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, N,N-dimethylformamide and polyvinylpyrrolidone is 8.1g:3g:55mL:55mL:30g;

[0066] Furthermore, the polyvinylpyrrolidone is sourced from Jinan Zhengkang Chemical Co., Ltd., and its model number is K30.

[0067] Step A2: Mix sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol and deionized water, stir for 20 min in an air atmosphere at a stirring speed of 400 rpm and a temperature of 60°C, then add the precursor fiber, ultrasonically disperse for 10 min, then add manganese sulfate solution, continue the reaction for 6 h, centrifuge, filter, wash and dry to obtain composite precursor fiber.

[0068] Furthermore, in step A2: the ratio of sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol, deionized water, precursor fiber, and manganese sulfate solution is 3g:1.2g:1.2g:100mL:300mL:1.7g:10mL, and the mass concentration of manganese sulfate solution is 0.1g / mL;

[0069] Furthermore, the polyacrylic acid is sourced from Jiangsu Maikai Biotechnology Co., Ltd., and its model number is PAA 980.

[0070] Step A3: Mix ferric nitrate nonahydrate, cobalt nitrate hexahydrate, and deionized water, stir, add sodium hydroxide solution, adjust the pH to 10, then add composite precursor fiber, react for 2 hours at a stirring rate of 150 rpm and a temperature of 80℃, centrifuge, filter, wash, and dry to obtain secondary composite precursor fiber, transfer the secondary composite precursor fiber to a tube furnace, calcine for 2 hours at a temperature of 600℃ in an air atmosphere with a heating rate of 3℃ / min, cool, and obtain modified manganese tetroxide fiber material;

[0071] Furthermore, in step A3: the ratio of ferric nitrate nonahydrate, cobalt nitrate hexahydrate, deionized water, and composite precursor fiber is 4.1g:1.5g:90mL:1.1g, and the molar concentration of sodium hydroxide solution is 5mol / L.

[0072] The modified polysiloxane is prepared by the following steps:

[0073] Step B1: Boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane and diethylene glycol dimethyl ether were mixed and reacted at 90°C for 2 hours under nitrogen protection with a stirring rate of 150 rpm. The temperature was then increased to 110°C and the reaction was continued for 60 minutes. Hydroquinone and stannous chloride were added while stirring, and the temperature was increased to 150°C and the reaction was continued for 6 hours. The mixture was then evaporated under reduced pressure and dried to obtain the aminosiloxane prepolymer.

[0074] Furthermore, in step B1, the ratio of boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane, diethylene glycol dimethyl ether, hydroquinone, and stannous chloride is 1.25g:0.5g:7.95g:20mL:0.54g:0.012g.

[0075] Step B2: Nickel acetylacetone, aminosiloxane prepolymer and tetrahydrofuran are mixed and reacted at room temperature with a stirring rate of 120 rpm for 5 h. Then n-butyl ester and phenolic resin are added and the reaction is continued for 2 h. The mixture is then evaporated under reduced pressure and dried to obtain modified polysiloxane.

[0076] Furthermore, in step B2, the ratio of nickel acetylacetonate, aminosiloxane prepolymer, tetrahydrofuran, n-butyl ester and phenolic resin is 0.25g:1.8g:20mL:0.15g:1.3g.

[0077] Comparative Example 1: Compared with Example 3, the modified polysiloxane in the preparation process of the composite soft magnetic material in Example 3 was removed, while the other steps were the same.

[0078] Comparative Example 2: Compared with Example 3, the vertical orientation magnetic field condition in the preparation process of the composite soft magnetic material in Example 3 was removed, while the other steps were the same.

[0079] The composite soft magnetic materials prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 were subjected to DC soft magnetic performance testing. An external magnetic field of ±10000 Oe was applied, and the saturation magnetization was measured. The AC soft magnetic performance was then tested using a soft magnetic AC measurement device under the conditions of Bm = 0.05 T and a frequency range of 20 kHz to 150 kHz. The magnetic loss was also measured. The test results are shown in the table below.

[0080] Table 1 Performance Test Table

[0081]

[0082] As shown in the table, the test results show that when comparing Examples 1, 2, and 3 with Comparative Examples 1 and 2, Comparative Example 1 removed the modified polysiloxane in the preparation process of the composite soft magnetic material of Example 3. Due to the lack of dopant, its performance was partially reduced. Comparative Example 2 removed the vertical orientation magnetic field condition in the preparation process of the composite soft magnetic material of Example 3. The lack of the vertical orientation magnetic field prevented it from forming a three-dimensional anisotropic structure, thus affecting its soft magnetic properties.

[0083] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0084] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. An application of modified manganese tetroxide in soft magnets, characterized in that: The process includes the following steps: Step S1: Weigh the following raw materials by weight: 35-40 parts ferric oxide, 25-30 parts manganese oxide, 10-15 parts zinc oxide, 8-10 parts modified manganese tetroxide fiber material, 2.5-4 parts silicone resin, 0.8-1 parts modified polysiloxane and 50-60 parts xylene; Step S2: Mix silicone resin, modified polysiloxane and xylene, then add ferric oxide, manganese oxide, zinc oxide and modified manganese tetroxide fiber material and continue mixing. Add to mold, vacuum dry at 150℃ under vertical orientation magnetic field, press at 600MPa, then heat to 600℃ under argon protection at a heating rate of 1℃ / min and hold for 2h, then heat to 1300℃ at a heating rate of 5℃ / min and hold for 6h to obtain composite soft magnetic material; The modified manganese tetroxide fiber material is prepared by the following steps: Step A1: Mix ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, and N,N-dimethylformamide. Stir at 200-300 rpm and 35°C for 3.5-4 hours. Then add polyvinylpyrrolidone and stir at room temperature for 24 hours to obtain a spinning solution. Transfer the spinning solution into the syringe of an electrospinning device. Perform electrospinning with the needle 15 cm away from the collection device, a spinning flow rate of 0.3 mL / h, and a voltage of 15 kV to obtain precursor fibers. Step A2: Mix sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol and deionized water. Stir for 15-20 minutes in an air atmosphere at a stirring speed of 300-400 rpm and a temperature of 60°C. Then add the precursor fiber and ultrasonically disperse for 8-10 minutes. Add manganese sulfate solution and continue the reaction for 5-6 hours. Centrifuge, filter, wash and dry to obtain the composite precursor fiber. Step A3: Mix ferric nitrate nonahydrate, cobalt nitrate hexahydrate, and deionized water, stir, add sodium hydroxide solution, adjust the pH to 10, then add composite precursor fiber, react for 1.5-2 hours at a stirring rate of 120-150 rpm and a temperature of 80℃, centrifuge, filter, wash, and dry to obtain secondary composite precursor fiber, transfer the secondary composite precursor fiber to a tube furnace, calcine at 600℃ for 2 hours in an air atmosphere with a heating rate of 3℃ / min, cool, and obtain modified manganese tetroxide fiber material; The modified polysiloxane is prepared by the following steps: Step B1: Boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane and diethylene glycol dimethyl ether are mixed and reacted under nitrogen protection at a stirring rate of 120-150 rpm and a temperature of 90℃ for 1.5-2 h. The temperature is then raised to 110℃ and the reaction is continued for 40-60 min. Hydroquinone and stannous chloride are added while stirring, and the temperature is raised to 150℃ and the reaction is continued for 4-6 h. The mixture is then evaporated under reduced pressure and dried to obtain the aminosiloxane prepolymer. Step B2: Mix nickel acetylacetonate, aminosiloxane prepolymer and tetrahydrofuran, and react at room temperature with a stirring rate of 100-120 rpm for 3-5 h. Then add n-butyl ester and phenolic resin, and continue the reaction for 1.5-2 h. Dry under reduced pressure to obtain modified polysiloxane.

2. The application of modified manganese tetroxide in soft magnets according to claim 1, characterized in that: In step A1, the ratio of ferric nitrate nonahydrate, zinc nitrate hexahydrate, ethanol, N,N-dimethylformamide, and polyvinylpyrrolidone is 8-8.1g: 2.9-3g: 50-55mL: 50-55mL: 28-30g.

3. The application of modified manganese tetroxide in soft magnets according to claim 1, characterized in that: In step A2, the ratio of sodium hydroxide, hexadecyltrimethylammonium bromide, polyacrylic acid, ethanol, deionized water, precursor fiber, and manganese sulfate solution is 2.8-3g: 1-1.2g: 1-1.2g: 90-100mL: 280-300mL: 1.6-1.7g: 9.5-10mL, and the mass concentration of manganese sulfate solution is 0.1g / mL.

4. The application of modified manganese tetroxide in soft magnets according to claim 1, characterized in that: In step A3: the ratio of ferric nitrate nonahydrate, cobalt nitrate hexahydrate, deionized water and composite precursor fiber is 4-4.1g: 1.45-1.5g: 80-90mL: 1-1.1g, and the molar concentration of sodium hydroxide solution is 5mol / L.

5. The application of modified manganese tetroxide in soft magnets according to claim 1, characterized in that: In step B1, the ratio of boric acid, N-aminoethyl-3-aminopropylmethyldimethoxysilane, phenyltrimethoxysilane, diethylene glycol dimethyl ether, hydroquinone, and stannous chloride is 1.24-1.25g: 0.48-0.5g: 7.92-7.95g: 15-20mL: 0.51-0.54g: 0.01-0.012g.

6. The application of modified manganese tetroxide in soft magnets according to claim 1, characterized in that: In step B2: the ratio of nickel acetylacetonate, aminosiloxane prepolymer, tetrahydrofuran, n-butyl ester and phenolic resin is 0.24-0.25g: 1.5-1.8g: 15-20mL: 0.12-0.15g: 1.2-1.3g.

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