A magnetic powder core and a method for manufacturing the same

Abstract

The application discloses a kind of magnetic powder core and its preparation method, the preparation method of the magnetic powder core includes four steps such as preparation gas atomization iron silicon soft magnetic powder, insulation coating, press forming and annealing heat treatment etc..Among them, iron silicon soft magnetic powder is prepared by gas atomization process, so that iron silicon soft magnetic powder has good soft magnetic properties, and has the advantages of low price, high permeability, high resistivity, low coercivity, low loss, stable DC bias characteristics and good temperature stability.Subsequently, iron silicon soft magnetic powder is insulated coated;Because the substrate of gas atomized iron silicon magnetic powder is preheated and activated, and then ball milled with an insulation modifier, and then made by heat treatment process, the obtained iron silicon powder product has improved permeability performance and insulation coordination;After press forming and annealing heat treatment, a high-temperature-resistant and corrosion-resistant magnetic powder core product is finally obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alloy soft magnetic material preparation, and particularly relates to a magnetic powder core and a preparation method thereof. BACKGROUND

[0002] Metallic soft magnetic material is an important basic functional material in the electronic industry. Compared with traditional ferrite soft magnetic material, metallic soft magnetic powder core product is not easy to leak magnetic flux at high frequency due to its internal pore structure, and is not easy to be saturated under strong DC current condition, and is suitable for preparing power factor corrector, switching regulator, online noise filter, pulse flyback transformer and other electronic components, and is widely applied to many fields such as new energy vehicles, photovoltaic, information communication and consumer electronics. In the series of iron-based soft magnetic materials, the iron-silicon powder and its magnetic powder core have high cost performance, and are one of the materials with the largest quantity in the application market of metallic soft magnetic materials.

[0003] In order to improve the magnetic permeability performance of the existing iron-silicon magnetic powder, the insulation of the product is easily affected, and at the same time, the product has poor high-temperature resistance, corrosion resistance and stability, which limits the use efficiency of the product. SUMMARY

[0004] The purpose of the present application is to provide a magnetic powder core and a preparation method thereof, so as to solve the problem of poor high-temperature resistance, corrosion resistance and stability of the magnetic powder core.

[0005] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a preparation method of a magnetic powder core, comprising the following steps:

[0007] S1: preparing gas atomized iron-silicon soft magnetic powder, the gas atomized iron-silicon soft magnetic powder comprises the following elements in percentage by weight: Si: 4.5-6.5%, Ni: <0.05%, Cr: <0.05%, Cu: <0.05%, C: <0.03%, Mn: <0.05%, P: <0.04%, S: <0.03%, and the balance is Fe;

[0008] S2: insulation coating: the gas atomized iron-silicon soft magnetic powder is subjected to insulation coating, comprising the following steps:

[0009] S21: the gas atomized iron-silicon soft magnetic powder obtained in S1 is subjected to preheating activation treatment to obtain a preheated and activated iron-silicon magnetic powder base;

[0010] S22: the preheated and activated iron-silicon magnetic powder base and the insulation modifier are subjected to ball milling coating treatment at a weight ratio of 5:3, the ball milling rotation speed is 1000-1500 r / min, and the ball milling time is 1 h, to obtain an insulation coated soft magnetic powder;

[0011] The insulation modifier comprises dopamine modification liquid and forsterite-nano titanium dioxide sintered body, and the mass ratio of the dopamine modification liquid and the forsterite-nano titanium dioxide sintered body is (5-8) : 3.

[0012] S3: compression molding: screening the insulation coated soft magnetic powder before compression, mixing the screened insulation coated soft magnetic powder with a release agent, and compression molding a magnetic powder core matrix;

[0013] S4: annealing heat treatment: high-temperature annealing heat treatment of the magnetic powder core matrix to obtain a magnetic powder core.

[0014] In the preparation method of the magnetic powder core, the preparation method of the dopamine modification liquid is as follows:

[0015] S201: 5-8 parts of dopamine hydrochloride are added into 25-30 parts of water, then 2-4 parts of sodium silicate solution and 1-3 parts of silane coupling agent are added, and stirring is uniformly carried out to obtain dopamine-based medium liquid;

[0016] S202: nano calcium carbonate, dimethyl hydroxy silicone oil and silane coupling agent are treated by temperature stirring at a weight ratio of 3:7:1, and after stirring, nano calcium carbonate liquid is obtained;

[0017] The specific operation steps of the temperature stirring treatment are as follows:

[0018] firstly, stirring is carried out at a temperature of 50-55 DEG C and a rotating speed of 350-400 r / min for 1 h, then the rotating speed is kept constant, and then the temperature is raised to 70 DEG C at a rate of 1-3 DEG C / min, and stirring is continued for 2 h;

[0019] S203: 5-8 parts of halloysite and 2-5 parts of silicon carbide are added into 5-8 parts of 5% mass fraction lanthanum chloride solution, and stirring is fully carried out, then suction filtration and drying are carried out, then sintering is carried out at 150-170 DEG C for 1 h, and finally air cooling is carried out to room temperature to obtain halloysite / silicon carbide composite;

[0020] S204: 3-5 parts of halloysite / silicon carbide composite, 1-2 parts of sodium metaborate and 2-4 parts of cerium oxide are added into 5-8 parts of nano calcium carbonate liquid for ball milling improvement, the ball milling rotating speed is 1500 r / min, and the ball milling time is 1 h, after the ball milling, suction filtration and drying are carried out to obtain modified nano filler agent;

[0021] S205: the modified nano filler agent and dopamine-based medium liquid are ultrasonically treated at a weight ratio of 2:5, and after ultrasonic treatment, dopamine modification liquid is obtained;

[0022] The silane coupling agent is silane coupling agent KH550, the mass fraction of the sodium silicate solution is 2-5%, the ultrasonic power for ultrasonic treatment is 350-400 W, and the ultrasonic time is 1 h.

[0023] The average particle size of the halloysite is 3.5-5 μm, and the average length-diameter ratio is 7-12.

[0024] The preparation method of the magnesium olivine-nano titanium dioxide sintered body is as follows:

[0025] S206: 2-4 parts of nano silicon sol are dispersed into 5-8 parts of a chitosan solution, and then 1-2 parts of sodium carboxymethyl cellulose are added, and stirred uniformly to obtain a modified solution; the mass fraction of the chitosan solution is 3-4%;

[0026] S207: 5-8 parts of nano titanium dioxide and 1-3 parts of barium sulfate are immersed into 6-10 parts of the modified solution and stirred fully, and then are subjected to suction filtration and drying to obtain a nano titanium dioxide modified body;

[0027] S208: 4-7 parts of the nano titanium dioxide modified body, 2-5 parts of magnesium olivine, and 3-5 parts of a 5% mass fraction yttrium nitrate solution are subjected to ball milling treatment, the rotating speed of the ball milling treatment is 750-1050 r / min, and the ball milling time is 2 h; after the ball milling treatment, suction filtration and drying are performed, and then heat calcination treatment is performed, so that a magnesium olivine-nano titanium dioxide sintered body is obtained;

[0028] The specific steps of the heat calcination treatment are as follows: first, the temperature is raised to 175 ℃ at a rate of 1-3 ℃ / min, and sintering is performed for 1 h; then, the temperature is raised to 300 ℃ at a rate of 2-4 ℃ / min, and the temperature is maintained for 45 min; finally, the temperature is allowed to decrease to room temperature.

[0029] In the preparation method of the magnetic powder core, the preheating activation temperature is 350-370 ℃, and the activation time is 20 min.

[0030] In the preparation method of the magnetic powder core, in the step S3, the mesh number of the sieve used for sieving before pressing is 80-200 meshes, and the addition amount of the release agent accounts for 0.3-0.6% of the total weight of the insulating coated soft magnetic powder and the release agent.

[0031] In the preparation method of the magnetic powder core, in the step S4, the annealing temperature of the high-temperature annealing heat treatment is 650-850 ℃, and the annealing time is 30-120 min.

[0032] In the preparation method of the magnetic powder core, in the step S1, the following steps are included:

[0033] S11: proportioning: according to the proportioning, the gaseous-atomized iron-silicon soft magnetic powder raw material, the slag removing agent, and the deoxidizing agent are weighed;

[0034] S12: alloy smelting: the gas atomized iron silicon soft magnetic powder raw material is heated and smelted, a deslagging agent and a deoxidizing agent are added, and stirring is performed; after stirring, the slag is removed, and an alloy melt is obtained;

[0035] S13: gas atomization powdering: the alloy melt is poured into a tundish, the alloy melt flows into a gas atomization chamber from a flow guide pipe at the bottom of the tundish, the alloy melt is atomized by high-pressure nitrogen gas, the alloy melt is broken into droplets, and after cooling and solidification, the semi-finished powder is obtained by sedimentation;

[0036] S14: sieving: after being cooled to room temperature, the semi-finished powder is sieved once; after high-temperature nitrogen gas annealing treatment, the semi-finished powder is sieved twice, and the gas atomized iron silicon soft magnetic powder is obtained.

[0037] In the preparation method of the magnetic powder core, in the step S11, the addition amount of the deslagging agent is 0.15-0.35% of the total mass of the gas atomized iron silicon soft magnetic powder raw material, and the addition amount of the deoxidizing agent is 0.20-0.40% of the total mass of the gas atomized iron silicon soft magnetic powder raw material;

[0038] In the step S12, the temperature of the alloy smelting is 1600-1650 DEG C, and the standing time is 0.5-2.5 min;

[0039] In the step S13, the alloy melt pouring temperature is 1630-1660 DEG C; the pressure of the high-pressure nitrogen gas is 3.5-5.0 MPa; and the temperature in the tundish is 1000-1250 DEG C;

[0040] The material of the flow guide pipe is boron nitride or zirconium oxide, and the diameter of the flow guide pipe is 4.0-7.0 mm;

[0041] In the step S14, the mesh number of the first sieving screen is 60-100 mesh, and the mesh number of the second sieving screen is 100-325 mesh; and in the high-temperature nitrogen gas annealing treatment, the annealing temperature is 700-1050 DEG C, and the annealing time is 25-60 min.

[0042] The application further provides a magnetic powder core prepared by the above preparation method of the magnetic powder core.

[0043] One of the technical solutions in the application can have the following beneficial effects:

[0044] The preparation method of the magnetic powder core comprises four steps of preparing an aerosolized iron-silicon soft magnetic powder, insulating coating, press forming and annealing heat treatment. The iron-silicon soft magnetic powder is prepared by the aerosolization process, so that the iron-silicon soft magnetic powder has good soft magnetic properties, and has the advantages of low price, high magnetic permeability, high resistivity, low coercivity, low loss, stable DC bias characteristics and good temperature stability. Subsequently, the iron-silicon soft magnetic powder is insulating coated; the aerosolized iron-silicon magnetic powder matrix is preheated and activated, then ball milled with an insulating modifier, and then formed by a heat treatment process, so that the magnetic permeability performance and insulation of the obtained iron-silicon powder product are improved in coordination; after press forming and annealing heat treatment, a high-temperature-resistant and corrosion-resistant magnetic powder core product is finally obtained. BRIEF DESCRIPTION OF DRAWINGS

[0045] Fig. 1 is a micro-morphology diagram of the aerosolized iron-silicon soft magnetic powder obtained in Example 1 in the present application;

[0046] Fig. 2 is a micro-morphology diagram of the aerosolized iron-silicon soft magnetic powder obtained in Example 2 in the present application;

[0047] Fig. 3 is a micro-morphology diagram of the aerosolized iron-silicon soft magnetic powder obtained in Example 3 in the present application;

[0048] Fig. 4 is a micro-morphology diagram of the aerosolized iron-silicon soft magnetic powder obtained in Example 4 in the present application. DETAILED DESCRIPTION

[0049] The technical solutions of the present application will be further described below through specific embodiments. In order to facilitate the understanding of the present application, the present application will be described more fully below. The present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0050] Unless specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or according to the product instructions are used. Unless otherwise specified, the reagents or instruments used are conventional products that can be obtained commercially.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0052] The present application provides a preparation method of a magnetic powder core, comprising the following steps:

[0053] S1: preparing an aerosolized iron-silicon soft magnetic powder, the aerosolized iron-silicon soft magnetic powder comprising the following elements in percentage by weight: Si: 4.5-6.5%, Ni: <0.05%, Cr: <0.05%, Cu: <0.05%, C: <0.03%, Mn: <0.05%, P: <0.04%, S: <0.03%, and the balance being Fe;

[0054] S2: insulating coating: insulating coating the aerosolized iron-silicon soft magnetic powder, comprising the following steps:

[0055] S21: preheating and activating the aerosolized iron-silicon soft magnetic powder obtained in S1 to obtain a preheated and activated iron-silicon magnetic powder base;

[0056] S22: ball milling the preheated and activated iron-silicon magnetic powder base and an insulating modifier at a weight ratio of 5:3 at a ball milling speed of 1000-1500 r / min for 1 h to obtain an insulating coated soft magnetic powder;

[0057] The insulating modifier comprises a dopamine modified liquid and a forsterite-nano titanium dioxide sintered body, and the mass ratio of the dopamine modified liquid to the forsterite-nano titanium dioxide sintered body is (5-8):3.

[0058] S3: press forming: sieving the insulating coated soft magnetic powder before press forming, mixing the sieved insulating coated soft magnetic powder with a release agent, and press forming the mixture into a magnetic powder core base;

[0059] S4: annealing heat treatment: high-temperature annealing heat treatment of the magnetic powder core base to obtain a magnetic powder core.

[0060] The preparation method of the magnetic powder core comprises four steps of preparing an aerosolized iron-silicon soft magnetic powder, insulating coating, press forming, and annealing heat treatment. The iron-silicon soft magnetic powder is prepared by an aerosolization process, so that the iron-silicon soft magnetic powder has good soft magnetic properties and the advantages of low price, high magnetic permeability, high resistivity, low coercivity, low loss, stable DC bias characteristics, and good temperature stability.

[0061] Subsequently, the iron-silicon soft magnetic powder is insulating coated. Since the aerosolized iron-silicon magnetic powder base is preheated and activated, then ball milled with an insulating modifier, and then processed by a heat treatment process, the magnetic permeability performance and insulation of the obtained iron-silicon powder product are improved in coordination. After press forming and annealing heat treatment, a high-temperature-resistant and corrosion-resistant magnetic powder core product is finally obtained.

[0062] The insulating modifier is prepared by mixing and matching dopamine modification liquid and forsterite-nano titanium dioxide sintered body, the dopamine modification liquid is prepared by mixing and matching hydrochloric acid dopamine, water, sodium silicate solution and silane coupling agent, the mixing and matching of the raw materials is used as the base agent, the modified nano filler agent is dispersed in the dopamine-based medium liquid, which can be better mixed and matched with the forsterite-nano titanium dioxide sintered body, so as to improve the aerosolized iron-silicon magnetic powder matrix, and the performance of the product is further improved.

[0063] In specific embodiments, the pressing pressure of the press forming is 10-30 T / cm 2 .

[0064] Specifically, the preparation method of the dopamine modification liquid is as follows:

[0065] S201: 5-8 parts of hydrochloric acid dopamine is added to 25-30 parts of water, then 2-4 parts of sodium silicate solution and 1-3 parts of silane coupling agent are added, and stirring is uniformly carried out to obtain a dopamine-based medium liquid;

[0066] S202: Nano calcium carbonate, dimethyl hydroxy silicone oil and silane coupling agent are heated and stirred according to a weight ratio of 3:7:1, and after stirring, nano calcium carbonate liquid is obtained;

[0067] The specific operation steps of the heating and stirring treatment are as follows:

[0068] First, stirring is carried out at a temperature of 50-55 DEG C and a rotating speed of 350-400 r / min for 1 h, then the rotating speed is kept constant, and then the temperature is raised to 70 DEG C at a rate of 1-3 DEG C / min, and stirring is continued for 2 h;

[0069] S203: 5-8 parts of halloysite and 2-5 parts of silicon carbide are added to 5-8 parts of 5% mass fraction lanthanum chloride solution, and stirring is fully carried out, then suction filtration and drying are carried out, then sintering is carried out at 150-170 DEG C for 1 h, and finally air cooling is carried out to room temperature to obtain halloysite / silicon carbide composite;

[0070] S204: 3-5 parts of halloysite / silicon carbide composite, 1-2 parts of sodium metaborate and 2-4 parts of cerium oxide are added to 5-8 parts of nano calcium carbonate liquid for ball milling improvement, the ball milling rotating speed is 1500 r / min, and the ball milling time is 1 h, after the ball milling, suction filtration and drying are carried out to obtain modified nano filler agent;

[0071] S205: The modified nano filler agent and the dopamine-based medium liquid are ultrasonically treated according to a weight ratio of 2:5, and after ultrasonic treatment, dopamine modification liquid is obtained;

[0072] The silane coupling agent is silane coupling agent KH550, the mass fraction of the sodium silicate solution is 2-5%, the ultrasonic power of the ultrasonic treatment is 350-400 W, and the ultrasonic time is 1 h.

[0073] The modified nano-filler agent is obtained by heating and stirring nano calcium carbonate, dimethyl hydroxyl silicone oil and silane coupling agent KH560, which can optimize the interface insulation of nano calcium carbonate, and better adjust halloysite / silicon carbide composite, sodium metaborate and cerium oxide.

[0074] Specifically, the average particle size of the halloysite is 3.5-5 μm, and the average ratio of length to diameter is 7-12.

[0075] The halloysite with the above particle size and length to diameter ratio can be better compounded with silicon carbide, and the stability of the halloysite / silicon carbide composite is improved.

[0076] Specifically, the preparation method of the forsterite-nano titanium dioxide sintered body is as follows:

[0077] S206: 2-4 parts of nano silicon sol are dispersed into 5-8 parts of chitosan solution, then 1-2 parts of sodium carboxymethyl cellulose are added, and the mixture is stirred uniformly to obtain a modified solution; the mass fraction of the chitosan solution is 3-4%;

[0078] S207: 5-8 parts of nano titanium dioxide and 1-3 parts of barium sulfate are immersed into 6-10 parts of the modified solution and stirred fully, then filtered and dried to obtain a nano titanium dioxide modified body;

[0079] S208: 4-7 parts of the nano titanium dioxide modified body, 2-5 parts of forsterite and 3-5 parts of yttrium nitrate solution with a mass fraction of 5% are subjected to ball milling treatment, the rotation speed of the ball milling treatment is 750-1050 r / min, and the ball milling time is 2 h; after the ball milling treatment, the mixture is filtered and dried, and then subjected to heat calcination treatment, thereby obtaining a forsterite-nano titanium dioxide sintered body.

[0080] The specific steps of the heat calcination treatment are as follows: first, the temperature is increased to 175 ℃ at a rate of 1-3 ℃ / min, and then sintered for 1 h; then, the temperature is increased to 300 ℃ at a rate of 2-4 ℃ / min, and then kept for 45 min; finally, the temperature is decreased to room temperature.

[0081] The magnesium olivine-nano titanium dioxide sintered body is treated by immersing nano titanium dioxide and barium sulfate into a modified solution, the modified solution is prepared by mixing nano silicon sol, chitosan solution and sodium carboxymethyl cellulose; meanwhile, the magnesium olivine and 5% yttrium nitrate solution are treated by ball milling, the raw materials are combined and matched, the nano titanium dioxide and the magnesium olivine are used as the matrix, the raw materials are matched and coordinated, and then the heat calcination treatment is performed, the temperature is increased to 175℃ at a rate of 1-3℃ / min, sintered for 1h, and then the temperature is increased to 300℃ at a rate of 2-4℃ / min, and the temperature is maintained for 45min.

[0082] The step-by-step heat calcination improvement process is adopted to enhance the matrix activity of the nano titanium dioxide and the magnesium olivine, so that the dopamine modified liquid can be better matched, and then the gas atomized iron silicon soft magnetic powder coating is improved, and the performance of the product is further improved.

[0083] Specifically, the preheating activation temperature is 350-370℃, and the activation is 20min.

[0084] The above temperature can remove the surface adsorbates and volatile components, eliminate the oxidation layer or passivation film, activate the surface of the magnetic powder particles, improve the diffusion capacity, provide kinetic conditions for the grain growth and densification in the subsequent high temperature annealing or sintering process, promote the sintering activity, and optimize the soft magnetic performance of the magnetic core.

[0085] Specifically, in the step S3, the screen mesh size of the pre-pressing screening is 80-200 meshes, and the addition amount of the release agent accounts for 0.3-0.6% of the total weight of the insulating coated soft magnetic powder and the release agent.

[0086] Through the pre-pressing screening step, the large particles can avoid scratching the mold surface during pressing, prolonging the service life of the mold; at the same time, the large particles of the insulating coated soft magnetic powder can prevent local oxidation or grain boundary defects during the annealing process, resulting in increased magnetic core loss or decreased mechanical strength.

[0087] The release agent lubricates the contact interface between the mold surface and the magnetic powder particles, reduces the friction between them, thereby reducing the demolding resistance and reducing the occurrence of sticking after pressing; in addition, the release agent can also coat the surface of the insulating coated soft magnetic powder, reduce the adhesion between the particles, enhance the flowability of the powder, make the powder more evenly distributed in the mold, reduce the density gradient of the green body after pressing, and improve the magnetic performance consistency of the magnetic powder core.

[0088] Specifically, in the step S4, the annealing temperature of the high temperature annealing heat treatment is 650-850℃, and the annealing time is 30-120min.

[0089] The annealing temperature and time directly affect the microstructure of the magnetic powder core. The annealing temperature and time in the above range can maximize the magnetic properties while avoiding the risk of crystallization or oxidation.

[0090] Further, in the step S1, the following steps are included:

[0091] S11: Proportioning: According to the proportioning, the aerosolized iron-silicon soft magnetic powder raw material, the slag remover and the deoxidizer are weighed;

[0092] S12: Alloy smelting: The aerosolized iron-silicon soft magnetic powder raw material is heated and smelted, the slag remover and the deoxidizer are added, and stirring is performed; after stirring, the slag is settled and the alloy melt is obtained;

[0093] S13: Aerosolized powdering: The alloy melt is poured into a tundish, and the alloy melt flows into the aerosolizing chamber from the flow guide pipe at the bottom of the tundish, and the alloy melt is broken into droplets by high-pressure nitrogen gas, and after cooling and solidification, the semi-finished powder is obtained by settling;

[0094] S14: Sieving: After being cooled to room temperature, the semi-finished powder is sieved once; after high-temperature nitrogen gas annealing treatment, the aerosolized iron-silicon soft magnetic powder is obtained after secondary sieving.

[0095] By using the above steps, the purposes of low-temperature smelting and low-temperature aerosolization can be achieved, and the aerosolized iron-silicon soft magnetic powder can be prepared by using high-pressure nitrogen gas, which can overcome the problem of oxidation and slagging caused by the difference in melting point of iron-silicon in a non-vacuum state, thereby avoiding the problem of slag blocking the nozzle and causing the aerosolization process to stop, and realizing the process of aerosolization in a non-vacuum state, which can avoid the use of expensive vacuum equipment and complex vacuum operation, and the production process is simple, the production efficiency is high, and the production cost can be greatly reduced.

[0096] Further, in the step S11, the addition amount of the slag remover is 0.15-0.35% of the total mass of the aerosolized iron-silicon soft magnetic powder raw material, and the addition amount of the deoxidizer is 0.20-0.40% of the total mass of the aerosolized iron-silicon soft magnetic powder raw material;

[0097] In the step S12, the temperature of alloy smelting is 1600-1650℃, and the time of standing is 0.5-2.5min;

[0098] In the step S13, the pouring temperature of the alloy melt is 1630-1660℃; the pressure of the high-pressure nitrogen gas is 3.5-5.0MPa; and the temperature in the tundish is 1000-1250℃;

[0099] The material of the flow guide pipe is boron nitride or zirconium oxide, and the diameter of the flow guide pipe is 4.0-7.0mm;

[0100] In the step S14, the mesh number of the sieve for the first screening is 60-100 mesh, and the mesh number of the sieve for the second screening is 100-325 mesh; and in the high-temperature nitrogen annealing treatment, the annealing temperature is 700-1050 DEG C, and the annealing time is 25-60 min.

[0101] The commercially available type of the slag removing agent is F2 slag removing agent, and the deoxidizer is silicon-calcium particles. The deoxidizer can react with oxygen in the alloy melt to generate compounds which are easy to remove. The slag removing agent is used to remove the metal slag in the smelting process, thereby avoiding the problem that the metal slag blocks the pipeline and causes the gas atomization to be unable to continue.

[0102] The gas atomized iron-silicon soft magnetic powder prepared by the above method has the advantages of good sphericity, low oxygen content, stable composition and high production efficiency, and the magnetic powder core prepared thereby has high DC bias and low loss.

[0103] The application further provides a magnetic powder core prepared by the above method.

[0104] Example 1

[0105] A method for preparing a magnetic powder core comprises the following steps:

[0106] A method for preparing a gas atomized iron-silicon soft magnetic powder comprises the following steps:

[0107] Proportioning: according to the proportioning, the gas atomized iron-silicon soft magnetic powder raw material, 0.20% slag removing agent and 0.30% deoxidizer are weighed; wherein the Si content in the gas atomized iron-silicon soft magnetic powder is 5.5%;

[0108] Alloy smelting: the gas atomized iron-silicon soft magnetic powder raw material is heated and smelted, the slag removing agent and the deoxidizer are added, and stirring is performed; after stirring, standing and slagging are performed to obtain an alloy melt; wherein the temperature of the alloy smelting is 1630-1640 DEG C, and the standing time is 1.5 min.

[0109] Gas atomization powdering: the alloy melt is poured into a tundish, the alloy melt flows into a gas atomization chamber from a flow guide pipe at the bottom of the tundish, high-pressure nitrogen gas is used to atomize the alloy melt, the alloy melt is broken into droplets, and after cooling and solidification, a semi-finished powder is obtained by sedimentation; wherein the pouring temperature of the alloy melt is 1650-1660 DEG C; the pressure of the high-pressure nitrogen gas is 4.7-4.8 MPa; the temperature in the tundish is 1200 DEG C; the material of the flow guide pipe is boron nitride, and the diameter of the flow guide pipe is 4.5 mm.

[0110] Screening: after being reduced to room temperature, the semi-finished powder is screened once; after being annealed at 850 DEG C for 60 min, the gas atomized iron-silicon soft magnetic powder is obtained after being screened twice; wherein the mesh number of the screen for the first screening is 100 meshes, and the mesh number of the screen for the second screening is 325 meshes;

[0111] Insulating coating, comprising the following steps:

[0112] The preheating activated iron-silicon magnetic powder matrix and the insulating modifier are ball milled at a weight ratio of 5:3, the ball milling speed is 1000 r / min, and the ball milling time is 1 h, to obtain the insulating coated soft magnetic powder;

[0113] The insulating modifier comprises a dopamine modified liquid and a forsterite-nano titanium dioxide sintered body, and the mass ratio of the dopamine modified liquid to the forsterite-nano titanium dioxide sintered body is 5:3;

[0114] The preheating activation temperature of the embodiment is 350 DEG C, and the activation time is 20 min;

[0115] The preparation method of the dopamine modified liquid of the embodiment is as follows:

[0116] 5 parts of dopamine hydrochloride are added to 25 parts of water, and then 2 parts of sodium silicate solution and 1 part of silane coupling agent are added, and the mixture is stirred uniformly to obtain a dopamine-based medium liquid;

[0117] Preparation of modified nano filler agent:

[0118] Nano calcium carbonate, dimethyl hydroxyl silicone oil and silane coupling agent are heated and stirred at a weight ratio of 3:7:1, and after stirring, nano calcium carbonate liquid is obtained. The specific operation steps of heating and stirring are as follows: first, stirring at a temperature of 50 DEG C and a speed of 350 r / min for 1 h, keeping the constant speed, then heating to 70 DEG C at a rate of 1 DEG C / min, and continuing to stir for 2 h;

[0119] 5 parts of halloysite and 2 parts of silicon carbide are added to 5 parts of a 5% mass fraction lanthanum chloride solution and stirred thoroughly, then filtered and dried, and then sintered at 150 DEG C for 1 h, and finally air-cooled to room temperature to obtain a halloysite / silicon carbide composite;

[0120] 3 parts of halloysite / silicon carbide composite, 1 part of sodium metaborate and 2 parts of cerium oxide are added to 5 parts of nano calcium carbonate liquid and ball milled, the ball milling speed is 1500 r / min, and the ball milling time is 1 h, after ball milling, the mixture is filtered and dried to obtain a modified nano filler agent;

[0121] The modified nano filler agent and the dopamine-based medium liquid are ultrasonically treated at a weight ratio of 2:5, and after ultrasonic treatment, a dopamine modified liquid is obtained;

[0122] The silane coupling agent of the embodiment is silane coupling agent KH550; the mass fraction of the sodium silicate solution is 2%; the ultrasonic power of the ultrasonic treatment is 350W, and the ultrasonic time is 1h;

[0123] The average particle size of the halloysite of the embodiment is 3.5μm, and the average ratio of length to diameter is 7;

[0124] The preparation method of the forsterite-nano titanium dioxide sintered body of the embodiment is as follows:

[0125] 2 parts of nano silicon sol are dispersed into 5 parts of chitosan solution, then 1 part of sodium carboxymethyl cellulose is added, and the mixture is stirred uniformly to obtain a modified solution; the mass fraction of the chitosan solution is 3%;

[0126] 5 parts of nano titanium dioxide and 1 part of barium sulfate are immersed into 6 parts of the modified solution and stirred fully, and then are subjected to suction filtration and drying to obtain a nano titanium dioxide modified body;

[0127] 4 parts of the nano titanium dioxide modified body, 2 parts of forsterite and 3 parts of a yttrium nitrate solution with a mass fraction of 5% are subjected to ball milling treatment at a rotating speed of 750r / min for 2h; after the ball milling treatment, the mixture is subjected to suction filtration and drying, and then is subjected to heat calcination treatment to obtain a forsterite-nano titanium dioxide sintered body;

[0128] The specific steps of the heat calcination treatment are as follows: first, the temperature is raised to 175℃ at a rate of 1℃ / min, and then is kept for 1h; then, the temperature is raised to 300℃ at a rate of 2℃ / min, and is kept for 45min; finally, the mixture is cooled to room temperature;

[0129] Compression molding: the sieved insulated coated soft magnetic powder is mixed with a release agent, and then is compressed to form a magnetic powder core matrix; wherein, the mesh number of the sieve used for the sieving before compression is 200 meshes, and the amount of the release agent added accounts for 0.3% of the total weight of the insulated coated soft magnetic powder and the release agent;

[0130] Annealing heat treatment: the magnetic powder core matrix is subjected to high-temperature annealing heat treatment at 745℃ for 75min to obtain a magnetic powder core.

[0131] Example 2

[0132] The steps of Example 2 are the same as those of Example 1, except that in the step of preparing the gas atomized iron-silicon soft magnetic powder, 0.35% of a slag remover and 0.40% of a deoxidizer are used; and the Si content in the gas atomized iron-silicon soft magnetic powder is 5.8%;

[0133] The annealing temperature of the high-temperature nitrogen annealing treatment is 850℃, and the annealing time is 60min; the mesh number of the sieve used for the first sieving is 60 meshes, and the mesh number of the sieve used for the second sieving is 100 meshes;

[0134] In the insulation coating step, the following steps are included:

[0135] The preheating activated iron-silicon magnetic powder matrix and the insulation modifier are ball milled for coating treatment at a weight ratio of 5:3, a ball milling speed of 1500 r / min, and a ball milling time of 1 h;

[0136] The insulation modifier includes a dopamine modification liquid and a forsterite-nano titanium dioxide sintered body, and the mass ratio of the dopamine modification liquid to the forsterite-nano titanium dioxide sintered body is 8:3;

[0137] The preheating activation temperature of the embodiment is 370℃, and the activation time is 20 min;

[0138] The preparation method of the dopamine modification liquid of the embodiment is as follows:

[0139] First, 8 parts of hydrochloric acid dopamine are added to 30 parts of water, and then 4 parts of sodium silicate solution and 3 parts of silane coupling agent are added and stirred uniformly to obtain a dopamine-based medium liquid;

[0140] Preparation of the modified nano filler agent:

[0141] The nano calcium carbonate, dimethyl hydroxy silicone oil and silane coupling agent are warmed and stirred at a weight ratio of 3:7:1, and after the stirring is completed, a nano calcium carbonate liquid is obtained. The specific operation steps of the warming and stirring treatment are as follows: first, stirring is performed at a temperature of 55℃ and a speed of 400 r / min for 1 h, the constant speed is maintained, and then the temperature is raised to 70℃ at a rate of 3℃ / min, and the stirring is continued for 2 h;

[0142] 8 parts of halloysite and 5 parts of silicon carbide are added to 8 parts of a 5% mass fraction lanthanum chloride solution and stirred thoroughly, then suction filtration and drying are performed, and then sintering is performed at 170℃ for 1 h, and finally air cooling is performed to room temperature to obtain a halloysite / silicon carbide composite;

[0143] 5 parts of halloysite / silicon carbide composite, 2 parts of sodium metaborate and 4 parts of cerium oxide are added to 8 parts of nano calcium carbonate liquid for ball milling improvement, the ball milling speed is 1500 r / min, the ball milling time is 1 h, after the ball milling is completed, suction filtration and drying are performed to obtain a modified nano filler agent;

[0144] The modified nano filler agent and the dopamine-based medium liquid are ultrasonically treated at a weight ratio of 2:5, and after the ultrasonic treatment is completed, a dopamine modification liquid is obtained;

[0145] The silane coupling agent of the embodiment is silane coupling agent KH550, the mass fraction of the sodium silicate solution is 5%, the ultrasonic power of the ultrasonic treatment is 400 W, and the ultrasonic time is 1 h;

[0146] The average particle size of the halloysite of the embodiment is 5μm, and the average length-diameter ratio is 12;

[0147] The preparation method of the forsterite-nano titanium dioxide sintered body of the embodiment is as follows:

[0148] 4 parts of nano silicon sol were dispersed into 8 parts of a chitosan solution, followed by adding 2 parts of sodium carboxymethyl cellulose, and stirring to obtain a modified solution; the mass fraction of the chitosan solution was 4%;

[0149] 8 parts of nano titanium dioxide and 3 parts of barium sulfate were immersed into 10 parts of the modified solution and stirred fully, and then were subjected to suction filtration and drying to obtain a nano titanium dioxide modified body;

[0150] 7 parts of the nano titanium dioxide modified body, 5 parts of forsterite and 5 parts of a yttrium nitrate solution with a mass fraction of 5% were subjected to ball milling treatment at a rotation speed of 1050 r / min for 2 h; after the ball milling treatment, suction filtration and drying were performed, and then heat calcination treatment was performed, so that the forsterite-nano titanium dioxide sintered body was obtained;

[0151] The specific steps of the heat calcination treatment were as follows: first, the temperature was raised to 175 ℃ at a rate of 3 ℃ / min, and sintering was performed for 1 h; then, the temperature was raised to 300 ℃ at a rate of 4 ℃ / min, and the temperature was maintained for 45 min; finally, the temperature was allowed to decrease to room temperature in an air-cooling manner;

[0152] In the compression molding step, the mesh number of the sieve screen used for sieving before compression was 80 meshes, and the addition amount of the release agent accounted for 0.6% of the total weight of the insulating-coated soft magnetic powder and the release agent.

[0153] In the annealing heat treatment step, the magnetic powder core substrate was subjected to high-temperature annealing heat treatment at 745 ℃ for 80 min, so that the magnetic powder core was obtained.

[0154] Example 3

[0155] The steps of Example 3 were the same as those of Example 1, except that in the step of preparing the gas-atomized iron-silicon soft magnetic powder, 0.15% of a slag remover and 0.20% of a deoxidizer were used; the Si content in the gas-atomized iron-silicon soft magnetic powder was 6.0%;

[0156] The annealing temperature of the high-temperature nitrogen annealing treatment was 850 ℃, and the annealing time was 60 min; the mesh number of the sieve screen used for the first sieving was 80 meshes, and the mesh number of the sieve screen used for the second sieving was 200 meshes;

[0157] In the insulating coating step, the following steps were included:

[0158] The preheated and activated iron-silicon magnetic powder substrate and the insulating modifier were subjected to ball milling coating treatment at a weight ratio of 5:3, the ball milling rotation speed was 1250 r / min, and the ball milling time was 1 h;

[0159] The insulating modifier included a dopamine modified liquid and a forsterite-nano titanium dioxide sintered body, and the mass ratio of the dopamine modified liquid to the forsterite-nano titanium dioxide sintered body was 6.5:3.

[0160] The preheating activation temperature of this embodiment is 360℃, and the activation time is 20min;

[0161] The preparation method of the dopamine modification liquid of this embodiment is as follows:

[0162] First, 6.5 parts of dopamine hydrochloride is added to 27.5 parts of water, then 4 parts of sodium silicate solution and 3 parts of silane coupling agent are added, and stirring is performed until uniform, to obtain a dopamine-based medium liquid;

[0163] Preparation of modified nanofiller agent:

[0164] The nanometer calcium carbonate, dimethyl hydroxyl silicone oil and silane coupling agent are heated and stirred according to a weight ratio of 3:7:1, and after stirring is completed, a nanometer calcium carbonate liquid is obtained. The specific operation steps of the heating and stirring treatment are as follows: first, stirring is performed at a temperature of 52.5℃ and a rotation speed of 375r / min for 1h, and then the rotation speed is kept constant, and the temperature is raised to 70℃ at a rate of 2℃ / min, and stirring is continued for 2h;

[0165] 6.5 parts of halloysite and 3.5 parts of silicon carbide are added to 6.5 parts of a 5% mass fraction lanthanum chloride solution and stirred until fully mixed, then suction filtration and drying are performed, and then sintering is performed at 160℃ for 1h, and finally air cooling is performed to room temperature, to obtain a halloysite / silicon carbide composite;

[0166] 4 parts of halloysite / silicon carbide composite, 1.5 parts of sodium metaborate and 3 parts of cerium oxide are added to 6.5 parts of nanometer calcium carbonate liquid and ball milled for modification, the ball milling rotation speed is 1500r / min, and the ball milling time is 1h, after ball milling is completed, suction filtration and drying are performed, to obtain a modified nanofiller agent;

[0167] The modified nanofiller agent and the dopamine-based medium liquid are ultrasonically treated according to a weight ratio of 2:5, and after ultrasonic treatment is completed, a dopamine modification liquid is obtained;

[0168] The silane coupling agent of this embodiment is silane coupling agent KH550; the mass fraction of the sodium silicate solution is 3.5%; the ultrasonic power of the ultrasonic treatment is 375W, and the ultrasonic time is 1h;

[0169] The average particle size of the halloysite of this embodiment is 4.5μm, and the average length-diameter ratio is 9.5;

[0170] The preparation method of the forsterite-nano titanium dioxide sintered body of this embodiment is as follows:

[0171] 3 parts of nanometer silicon sol are dispersed in 6.5 parts of a chitosan solution, then 1.5 parts of sodium carboxymethyl cellulose is added, and stirring is performed until uniform, to obtain a modified solution; the mass fraction of the chitosan solution is 3.5%;

[0172] The 6.5 parts of nano-titanium dioxide and 2 parts of barium sulfate are immersed into 8 parts of the modified solution and stirred fully, and then filtered and dried to obtain the modified nano-titanium dioxide;

[0173] The 5.5 parts of the modified nano-titanium dioxide, 3.5 parts of forsterite and 4 parts of a 5% mass fraction yttrium nitrate solution are subjected to ball milling treatment at a speed of 900 r / min for 2 h; after the ball milling treatment, the mixture is filtered and dried, and then subjected to heat calcination treatment to obtain the forsterite-nano-titanium dioxide sintered body;

[0174] The specific steps of the heat calcination treatment are as follows: first, the temperature is raised to 175℃ at a rate of 2℃ / min, and then sintered for 1 h; then, the temperature is raised to 300℃ at a rate of 3℃ / min, and then kept for 45 min; finally, the temperature is cooled to room temperature.

[0175] In the pressing step, the screen mesh size of the pre-pressing screening is 100 meshes, and the addition amount of the release agent accounts for 0.4% of the total weight of the insulating coated soft magnetic powder and the release agent.

[0176] In the annealing heat treatment step, the magnetic powder core substrate is subjected to high-temperature annealing heat treatment at 800℃ for 75 min to obtain the magnetic powder core.

[0177] Example 4

[0178] The steps of Example 4 are the same as those of Example 1, except that in the step of preparing the gas-atomized iron-silicon soft magnetic powder, 0.20% of a slag remover and 0.30% of a deoxidizer are used; the Si content in the gas-atomized iron-silicon soft magnetic powder is 6.2%; the annealing temperature of the high-temperature nitrogen annealing treatment is 850℃, and the annealing time is 60 min.

[0179] In the annealing heat treatment step, the magnetic powder core substrate is subjected to high-temperature annealing heat treatment at 850℃ for 60 min to obtain the magnetic powder core.

[0180] The gas-atomized iron-silicon soft magnetic powders obtained in Examples 1-4 are subjected to powder performance detection, and the powder performance detection items include Si content, tap density (TD), oxygen content (O) and micro-morphology. The test results are shown in Table 1. The inductance, superposition and power consumption of the magnetic powder cores obtained in Examples 1-4 are detected, and the test results are shown in Table 2. The micro-morphology is observed by a scanning electron microscope. The micro-morphology of the gas-atomized iron-silicon soft magnetic powders obtained in Examples 1-4 is shown in Figs. 1-4 .

[0181] Table 1 - Powder performance detection results

[0182]

[0183] Table 2 - Magnetic core performance detection results

[0184]

[0185] From Table 1 and Table 2, it can be seen that the gas atomized iron-silicon soft magnetic powder prepared by the method has good sphericity, low oxygen content and stable composition, and the magnetic powder core prepared by the method has high DC bias and low loss.

[0186] Comparative Example 1

[0187] The difference from Example 1 is that the forsterite-nano titanium dioxide sintered body is not added in the insulation modifier.

[0188] Comparative Example 2

[0189] The difference from Example 1 is that the nano titanium dioxide modifier is not added in the preparation of the forsterite-nano titanium dioxide sintered body.

[0190] Comparative Example 3

[0191] The difference from Example 1 is that the preparation method of the nano titanium dioxide modifier is different:

[0192] 6.5 parts of nano titanium dioxide is immersed in 6.5 parts of chitosan solution, then 1.5 parts of sodium carboxymethyl cellulose is added, stirred thoroughly, and then filtered and dried to obtain the nano titanium dioxide modifier.

[0193] Comparative Example 4

[0194] The difference from Example 1 is that the forsterite-nano titanium dioxide sintered body is not prepared by ball milling treatment of forsterite and yttrium nitrate solution.

[0195] Comparative Example 5

[0196] The difference from Example 1 is that 6.5 parts of dopamine hydrochloride is added to 27.5 parts of water instead of preparing the dopamine modification solution.

[0197] Comparative Example 6

[0198] The difference from Example 1 is that the modified nano filler agent is not added in the dopamine modification solution.

[0199] Comparative Example 7

[0200] The difference from Example 1 is that the halloysite / silicon carbide composite is not added in the modified nano filler agent.

[0201] Comparative Example 8

[0202] The difference from Example 1 is that the preparation method of the halloysite / silicon carbide composite is different:

[0203] 6.5 parts of halloysite is added to 6.5 parts of 5% mass fraction lanthanum chloride solution and stirred thoroughly, and then filtered and dried.

[0204] Comparative Example 9

[0205] The difference from Example 1 is that sodium metaborate and cerium oxide are not added in the preparation of the modified nanofiller agent.

[0206] Comparative Example 10

[0207] The difference from Example 1 is that the nanometer calcium carbonate liquid is directly replaced by dimethyl hydroxyl silicone oil.

[0208] The products of Example 1 and Comparative Examples 1-10 are tested for breakdown voltage and effective magnetic permeability µ of 100 KHz, and the results are shown in Table 3. e

[0209] Table 3 - Results of breakdown voltage and effective magnetic permeability µ of 100 KHz e

[0210]

[0211] Based on the above tests, the products are placed at 75°C for 48h to test the high temperature resistance, and placed in 2% hydrochloric acid mist for 12h and then in 5% sodium chloride salt mist for 12h to test the corrosion resistance, and the test results are shown in Table 4.

[0212] Table 4 - Test results under high temperature and corrosion resistance conditions

[0213]

[0214] From Comparative Examples 1-10 and Example 1, as well as the tests under high temperature and corrosion resistance conditions, it can be seen that:

[0215] The product of Example 1 has excellent breakdown voltage and effective magnetic permeability, and both performances can be improved in coordination, and the performance stability of the product under high temperature conditions is significantly improved, and the performance stability under corrosion resistance conditions is also significantly improved, and the performance stability of the product is significantly improved.

[0216] In the insulation modifier of the present application, magnesium olivine-nano titanium dioxide sintered body and dopamine modified liquid are not added, 6.5 parts of hydrochloric acid dopamine are added to 27.5 parts of water instead of preparation, and the performance stability of the product appears a significant deterioration trend.

[0217] In the preparation of magnesium olivine-nano titanium dioxide sintered body, nano titanium dioxide modifier is not added, the preparation method of nano titanium dioxide modifier is different, and the magnesium olivine-nano titanium dioxide sintered body is not treated by ball milling with magnesium olivine and yttrium nitrate solution, and the performance of the product has a different degree of deterioration trend, and the magnesium olivine-nano titanium dioxide sintered body obtained by the specific method of the present application has the most significant product performance effect. ​​

[0218] The performance of the product has a deteriorating trend when the modified nano-filler agent is not added, the halloysite / silicon carbide composite is not added, the preparation method of the halloysite / silicon carbide composite is different, the sodium metaborate and cerium oxide are not added in the preparation of the modified nano-filler agent, and the nano-calcium carbonate liquid is directly replaced by dimethyl hydroxyl silicone oil. The performance of the product is greatly changed when the modified nano-filler agent is not added and the halloysite / silicon carbide composite is not added. The performance of the dopamine modified liquid prepared by using the specific method of the application in combination with the specific process of the nano-calcium carbonate liquid and the modified nano-filler agent is the most remarkable. The effect of the application is not as remarkable as that of the application when other methods are used instead.

[0219] The technical principles of the application are described above in combination with specific embodiments. These descriptions are only for explaining the principles of the application and cannot be interpreted as limiting the scope of protection of the application in any way. Based on the explanations herein, other specific embodiments of the application can be conceived by those skilled in the art without creative efforts, and these equivalent variations or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A method of producing a magnetic powder core, characterized by, The method comprises the following steps: S1: preparing an aerosolized iron-silicon soft magnetic powder, which comprises the following elements in percentage by weight: Si: 4.5-6.5%, Ni: <0.05%, Cr: <0.05%, Cu: <0.05%, C: <0.03%, Mn: <0.05%, P: <0.04%, S: <0.03%, and the balance of Fe; S2: insulation coating: the aerosolized iron-silicon soft magnetic powder is subjected to insulation coating, which comprises the following steps: S21: the aerosolized iron-silicon soft magnetic powder obtained in S1 is subjected to preheating activation treatment to obtain a preheating activated iron-silicon magnetic powder base; S22: the preheating activated iron-silicon magnetic powder base and an insulation modifier are subjected to ball milling coating treatment at a weight ratio of 5:3, the ball milling rotation speed is 1000-1500 r / min, and the ball milling time is 1 h to obtain an insulation coated soft magnetic powder; wherein the insulation modifier comprises a dopamine modified liquid and a forsterite-nano titanium dioxide sintered body, and the mass ratio of the dopamine modified liquid to the forsterite-nano titanium dioxide sintered body is (5-8):3; S3: press forming: the insulation coated soft magnetic powder is sieved before being pressed, the sieved insulation coated soft magnetic powder is mixed with a demolding agent, and a magnetic powder core base is formed by pressing; S4: annealing heat treatment: the magnetic powder core base is subjected to high-temperature annealing heat treatment to obtain a magnetic powder core; The preparation method of the dopamine modified liquid is as follows: S201: 5-8 parts of hydrochloric acid dopamine are added to 25-30 parts of water, then 2-4 parts of sodium silicate solution and 1-3 parts of silane coupling agent are added, and the mixture is stirred uniformly to obtain a dopamine-based medium liquid; S202: nano calcium carbonate, dimethyl hydroxy silicone oil and silane coupling agent are subjected to temperature stirring treatment at a weight ratio of 3:7:1, and the nano calcium carbonate liquid is obtained after stirring; The temperature stirring treatment comprises the following steps: firstly, stirring is performed at a temperature of 50-55 ℃ and a rotation speed of 350-400 r / min for 1 h, then the rotation speed is kept constant, and then the temperature is raised to 70 ℃ at a rate of 1-3 ℃ / min, and the stirring is continued for 2 h; S203: 5-8 parts of halloysite and 2-5 parts of silicon carbide are added to 5-8 parts of 5% mass fraction lanthanum chloride solution and stirred fully, then suction filtration and drying are performed, then sintering is performed at 150-170 ℃ for 1 h, and finally air cooling is performed to room temperature to obtain a halloysite / silicon carbide composite; S204: 3-5 parts of halloysite / silicon carbide composite, 1-2 parts of sodium metaborate and 2-4 parts of cerium oxide are added to 5-8 parts of nano calcium carbonate liquid for ball milling improvement, the ball milling rotation speed is 1500 r / min, and the ball milling time is 1 h, then suction filtration and drying are performed after the ball milling is completed to obtain a modified nano filler agent; S205: the modified nano filler agent and the dopamine-based medium liquid are subjected to ultrasonic treatment at a weight ratio of 2:5, and the dopamine modified liquid is obtained after the ultrasonic treatment is completed; The silane coupling agent is silane coupling agent KH550, the mass fraction of the sodium silicate solution is 2-5%, the ultrasonic power for the ultrasonic treatment is 350-400 W, and the ultrasonic time is 1 h; The preheating activation temperature is 350-370 ℃, and the activation time is 20 min; In the step S4, the annealing temperature of the high-temperature annealing heat treatment is 650-850℃, and the annealing time is 30-120min.

2. The method of producing a magnetic powder core according to claim 1, wherein The average particle size of the halloysite is 3.5-5μm, and the average ratio of length to diameter is 7-12.

3. The method of producing a magnetic powder core according to claim 1, wherein The preparation method of the forsterite-nano titanium dioxide sintered body is: S206: 2-4 parts of nano silicon sol are dispersed into 5-8 parts of chitosan solution, then 1-2 parts of sodium carboxymethyl cellulose are added, and stirring is uniformly carried out to obtain a modified solution; The mass fraction of the chitosan solution is 3-4%; S207: 5-8 parts of nano titanium dioxide and 1-3 parts of barium sulfate are immersed into 6-10 parts of the modified solution and stirred fully, then are extracted and dried to obtain a nano titanium dioxide modified body; S208: 4-7 parts of the nano titanium dioxide modified body, 2-5 parts of forsterite and 3-5 parts of a 5% mass fraction yttrium nitrate solution are ball milled, the rotating speed of the ball milling is 750-1050r / min, and the ball milling time is 2h; after the ball milling, extraction and drying are carried out, and then heat calcination treatment is carried out to obtain the forsterite-nano titanium dioxide sintered body; The specific steps of the heat calcination treatment are as follows: first, the temperature is raised to 175℃ at a rate of 1-3℃ / min, and sintering is carried out for 1h; then, the temperature is raised to 300℃ at a rate of 2-4℃ / min, and the temperature is kept for 45min; finally, the temperature is cooled to room temperature.

4. The method of producing a magnetic powder core according to claim 1, wherein In the step S3, the mesh number of the sieve screen used before the pressing is 80-200 meshes, and the adding amount of the release agent accounts for 0.3-0.6% of the total weight of the insulating coated soft magnetic powder and the release agent.

5. The method of producing a magnetic powder core according to claim 1, wherein In the step S1, the following steps are included: S11: proportioning: according to the proportioning, the gas atomized iron silicon soft magnetic powder raw material, the slag removing agent and the deoxidizing agent are weighed; S12: alloy smelting: the gas atomized iron silicon soft magnetic powder raw material is heated and smelted, the slag removing agent and the deoxidizing agent are added, and stirring is carried out; after the stirring, standing and slagging are carried out to obtain an alloy melt; S13: gas atomization powdering: the alloy melt is poured into a tundish, the alloy melt flows into a gas atomization chamber from a flow guide pipe at the bottom of the tundish, the alloy melt is atomized by high pressure nitrogen gas to break the alloy melt into liquid drops, and after cooling and solidification, the semi-finished powder is obtained by sedimentation; the pressure of the high pressure nitrogen gas is 3.5-5.0MPa; S14: sieving: after being cooled to room temperature, the semi-finished powder is sieved once; then, high temperature nitrogen annealing treatment is carried out, and after being sieved twice, the gas atomized iron silicon soft magnetic powder is obtained; In the step S14, in the high temperature nitrogen annealing treatment, the annealing temperature is 700-1050℃, and the annealing time is 25-60min; and the mesh number of the sieve screen used for the first sieving is 60-100 meshes, and the mesh number of the sieve screen used for the second sieving is 100-325 meshes.

6. A method of manufacturing a magnetic powder core according to claim 5, wherein In the step S11, the adding amount of the slag removing agent accounts for 0.15-0.35% of the total mass of the gas atomized iron silicon soft magnetic powder raw material, and the adding amount of the deoxidizing agent accounts for 0.20-0.40% of the total mass of the gas atomized iron silicon soft magnetic powder raw material; In the step S12, the temperature of the alloy smelting is 1600-1650℃, and the standing time is 0.5-2.5min; In the step S13, the alloy melt pouring temperature is 1630-1660 DEG C; the tundish in-bag temperature is 1000-1250 DEG C; The material of the flow guide pipe is boron nitride or zirconium oxide, and the diameter of the flow guide pipe is 4.0-7.0 mm.

7. A magnetic powder core, characterized by, The magnetic powder core is prepared by the method of any one of claims 1-6.

Images