A soft magnetic composite material and a preparation method of a corrosion-resistant magnetic core thereof

Abstract

The application relates to a soft magnetic composite material and a preparation method of a corrosion-resistant magnetic core thereof, and has the characteristics that the method comprises the following steps: S1, mixing a silane coupling agent, nano-oxide and an organic solvent to prepare a reaction liquid A; adding iron powder into the reaction liquid A, continuously stirring, filtering and vacuum drying the reaction precipitate to obtain coated iron powder; S2, pressing the coated iron powder; S3, pre-sintering the pre-pressed magnetic core; S4, preparing a reaction liquid B; performing electrophoretic sealing on the pre-formed magnetic core by taking the pre-formed magnetic core as an anode and taking the reaction liquid B as an electrolyte; S5, high-pressure forming the magnetic core after the electrophoretic sealing in the step S4 to obtain a high-pressure formed magnetic core; S6, mixing fluoride and isopropyl alcohol to prepare a reaction liquid C, immersing the high-pressure formed magnetic core in the reaction liquid C, and then performing drying and heat treatment. Compared with the prior art, the application has the advantages of low production cost, environmental protection, good corrosion resistance and insulation performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soft magnetic materials, and particularly relates to a soft magnetic composite material and a preparation method of a corrosion-resistant magnetic core thereof. BACKGROUND

[0002] The iron-based soft magnetic composite material is a high-performance metal soft magnetic composite material. In the fields of correction circuits, pulse flyback transformers, energy storage filter inductors and line filters, an integrally formed inductor prepared from the iron-based soft magnetic composite material has the advantages of easy forming, strong anti-electromagnetic interference performance, low noise and high frequency, and is increasingly applied. The traditional integrally formed inductor is composed of soft magnetic powder, a coil and an adhesive. The soft magnetic powder contributes to electromagnetic properties, and the adhesive contributes to blocking the transfer of eddy current between the powders to reduce loss. The magnetic core prepared by this method has good corrosion resistance due to the use of a resin adhesive, but is not resistant to high temperature.

[0003] A newly developed inorganic coated soft magnetic core is prepared by high-pressure pressing and sintering of iron powder coated with inorganic oxide. The magnetic core prepared by this method has good insulation, but has high porosity, poor corrosion resistance, is easy to oxidize and crack. For example, the Chinese invention patent application No. 202210117455.6 (application publication No. CN114664508A) "soft magnetic composite material and preparation method thereof, integrally formed inductor" discloses a magnetic core preparation method using epoxy resin adhesive, phenolic resin adhesive, cyanate ester or silicone resin as the binder, which effectively improves the salt mist resistance of the magnetic core. The Chinese invention patent application No. 202210631172.3 (application publication No. CN115206620A) "moisture-resistant soft magnetic composite material and preparation method thereof, integrally formed inductor" discloses a moisture-resistant soft magnetic composite material and a preparation method thereof, and an integrally formed inductor, which effectively suppresses the bursting phenomenon of the inductor during reflow soldering after moisture absorption. The methods of the above two patents both use resin as the binder, which can effectively improve the density and corrosion resistance of the magnetic core. However, the magnetic core prepared by using resin as the binder and barrier agent has poor temperature resistance, and there is a risk of significant reduction in the insulation of the magnetic core under high temperature working conditions. In addition, the amount of resin binder used is large, which is not conducive to environmental protection. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a soft magnetic composite material and a preparation method of a corrosion-resistant magnetic core thereof, which have low production cost, are environmentally friendly, have good corrosion resistance and insulation performance.

[0005] The technical solution adopted by the present application to solve the above technical problems is as follows: a soft magnetic composite material and a preparation method of a corrosion-resistant magnetic core thereof, characterized in that:

[0006] comprising the following steps:

[0007] S1, mixing silane coupling agent, nano-oxide and organic solvent to prepare reaction liquid A; adding iron powder into reaction liquid A, continuously stirring, and filtering and vacuum drying the reaction precipitate to obtain coated iron powder;

[0008] S2, pressing the coated iron powder to obtain a pre-pressed formed magnetic core;

[0009] S3, pre-sintering the pre-pressed formed magnetic core;

[0010] S4, mixing fluoride, divalent metal salt and deionized water to prepare reaction liquid B; performing electrophoretic sealing with the pre-formed magnetic core as an anode and reaction liquid B as an electrolyte, and then drying;

[0011] S5, placing the magnetic core after electrophoretic sealing obtained in step S4 into a mold for high-pressure forming to obtain a high-pressure formed magnetic core;

[0012] S6, mixing fluoride and isopropanol to prepare reaction liquid C, soaking the high-pressure formed magnetic core in reaction liquid C, and then drying and heat treating.

[0013] The coated iron powder prepared in step S1 has a core-shell structure with iron powder as the core and nano-particles modified by silane coupling agent as the coating layer.

[0014] To keep the coated iron powder at a low surface energy during the inductance forming and pressing process, preferably, the iron powder in step S1 is one or a mixture of different particle sizes of pure iron powder, carbonyl iron powder, iron-silicon powder and iron-silicon-aluminum powder.

[0015] Preferably, the mass ratio of silane coupling agent, nano-oxide and organic solvent in step S1 is 1:0.01-0.1:50-100, the mixing method is ultrasonic dispersion at room temperature for 30-60 min, the silane coupling agent is a mixture of one or more of KH550, KH560 and KH570, the nano-oxide is a mixture of one or both of nano-SiO2 and nano-TiO2, and the organic solvent is one of anhydrous ethanol and isopropanol.

[0016] Preferably, the mass ratio of iron powder to reaction liquid A in step S1 is 1:1-5, the reaction time is 2-4 h, and the drying temperature is 60-100℃.

[0017] Preferably, the pressing pressure in step S2 is 300-600 MPa, and the pressure holding time is 30-90 s.

[0018] Pre-sintering of the step S3 is preferably vacuum sintering or inert gas protection sintering, the pre-sintering temperature is 200-300 DEG C, and the pre-sintering time is 30-60 min; the inert gas of the inert gas protection sintering is nitrogen.

[0019] In order to make the fluoride construct low surface energy coated iron powder, preferably, the fluoride of the step S4 is a mixture of one or more of 60% polytetrafluoroethylene emulsion, perfluorodecyl trimethoxysilane and perfluorooctyl triethoxysilane, the divalent metal salt is a calcium salt or a magnesium salt; the mass ratio of the fluoride, the divalent metal salt and the solvent water is 1:0.1-0.5:50-100.

[0020] The electrophoretic hole sealing is carried out by electrophoresis treatment of a stainless steel plate as a cathode, the voltage is 60-90 V, the reaction time is 20-40 s, the electrolytic tank internal gas pressure is ≤-0.07 MPa; the drying temperature is 120-200 DEG C, and the time is 10-30 min.

[0021] Preferably, the pressure of the high-pressure forming of the step S5 is 900-1200 MPa, and the pressure maintaining time is 20-40 s.

[0022] Preferably, the fluoride of the step S6 is a mixture of one or more of 60% polytetrafluoroethylene emulsion, perfluorodecyl trimethoxysilane and perfluorooctyl triethoxysilane, the mass ratio of the fluoride and isopropyl alcohol is 1:10-20; the soaking reaction time of the high-pressure formed magnetic core in the reaction liquid C is 15-30 s; the temperature of the heat treatment is 120-150 DEG C, and the heat treatment time is 20-40 min.

[0023] Compared with the prior art, the advantages of the present application are that: on the basis of traditional soft magnetic iron powder inorganic coating, the surface energy of the coated iron powder is reduced by grafting F ion containing groups on the surface of the inorganic coating agent, so that the pressed magnetic core has good insulation and hydrophobic properties, and the magnetic core has good corrosion resistance and insulation performance; negative pressure electrophoretic hole sealing can make the reaction liquid enter the inside of the pre-pressed magnetic core, and the charged fluoride in the reaction liquid B can be deposited at the crack of the iron powder coating layer, so as to further improve the insulation and corrosion resistance of the magnetic core; the low surface energy coated iron powder and the corrosion resistant layer of the magnetic core constructed by the fluoride can effectively reduce the amount of resin used in the traditional magnetic core pressing process, reduce the production cost, and be more environmentally friendly.

[0024] The coated iron powder of the present application always maintains a low surface energy during the inductance forming and pressing process, reduces the risk of product sticking to the mold after pre-pressing and high-pressure forming, so that no lubricant is used in the magnetic core pressing process, which is conducive to reducing the production cost. DETAILED DESCRIPTION

[0025] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. The described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0026] Embodiment 1

[0027] (1) 10 g of KH560 and 0.1 g of nano-silica particles were added into 500 g of isopropyl alcohol, and after being stirred uniformly, ultrasonic dispersion was performed for 30 min to prepare a reaction liquid A; 100 g of pure iron powder was added into 100 g of the reaction liquid A, and stirring reaction was performed at room temperature for 4 h; after the reaction was completed, filtration and vacuum drying at 60 DEG C were performed to obtain coated iron powder.

[0028] (2) 10 g of the coated iron powder was placed in a pressing mold, and pre-pressing was performed to form a pre-formed magnetic core, and the forming pressure was 300 MPa, and the pressure maintaining time was 90 s.

[0029] (3) The pre-formed magnetic core was placed in a vacuum sintering furnace, and sintering was performed at 200 DEG C for 30 min.

[0030] (4) 10 g of emulsion containing 60% of polytetrafluoroethylene, 1 g of calcium chloride and 500 g of deionized water were mixed, and after being stirred sufficiently until dissolved, a reaction liquid B was prepared; the pre-formed magnetic core was used as an anode, a stainless steel plate was used as a cathode, and the reaction liquid B was used as an electrolyte to perform electrophoresis treatment, the treatment voltage was 60 V, the treatment time was 40 s, and the gas pressure in the electrolytic cell was -0.07 MPa; after the electrophoresis was completed, the magnetic core was dried, the temperature was 120 DEG C, and the time was 30 min.

[0031] (5) The magnetic core after the electrophoresis treatment was placed in a mold, and high-pressure forming was performed, and the pressure was 900 MPa, and the pressing time was 40 s.

[0032] (6) 10 g of perfluorodecyltrimethoxysilane was added into 100 g of isopropyl alcohol, and after being stirred sufficiently until mixed uniformly, a reaction liquid C was prepared; the high-pressure formed magnetic core was soaked in the reaction liquid C for 15 s; finally, drying and heat treatment were performed, the heat treatment temperature was 120 DEG C, and the time was 40 min, to obtain a soft magnetic core.

[0033] Embodiment 2

[0034] (1) 10 g KH560 and 0.5 g nano-silica particles were added to 750 g of isopropyl alcohol, stirred uniformly, and then dispersed using ultrasonic for 45 min to prepare a reaction liquid A; 100 g of pure iron powder was added to 300 g of the reaction liquid A, and stirred at room temperature for 3 h; after the reaction was completed, the coated iron powder was obtained by filtering and vacuum drying at 80°C.

[0035] (2) 10 g of the coated iron powder was placed in a pressing mold for pre-pressing and molding, and the molding pressure was 450 MPa and the pressure holding time was 60 s.

[0036] (3) Low-temperature pre-sintering: the pre-pressing and molding magnetic core was placed in a vacuum sintering furnace and sintered at 250°C for 45 min.

[0037] (4) 10 g of emulsion containing 60% polytetrafluoroethylene, 3 g of calcium chloride and 750 g of deionized water were mixed, and stirred until dissolved to prepare a reaction liquid B; the pre-molding magnetic core was used as the anode, a stainless steel plate was used as the cathode, and the reaction liquid B was used as the electrolyte for electrophoresis treatment, the treatment voltage was 75 V, the treatment time was 30 s, and the gas pressure in the electrolytic cell was -0.07 MPa; after the electrophoresis was completed, the magnetic core was dried at a temperature of 160°C for 20 min.

[0038] (5) High-pressure molding: the magnetic core after the electrophoresis hole sealing was placed in a mold, and pressed using a pressure of 1050 MPa for 30 s.

[0039] (6) 10 g of perfluorodecyltrimethoxysilane was added to 150 g of isopropyl alcohol, and stirred until mixed uniformly to prepare a reaction liquid C; the high-pressure molding magnetic core was soaked in the reaction liquid C for 22 s; finally, drying and heat treatment were performed, the heat treatment temperature was 135°C, and the time was 30 min, to obtain a soft magnetic core.

[0040] Example 3

[0041] (1) 10 g of KH560 and 1 g of nano-silica particles were added to 1000 g of isopropyl alcohol, stirred uniformly, and then dispersed using ultrasonic for 60 min to prepare a reaction liquid A; 100 g of pure iron powder was added to 500 g of the reaction liquid A, and stirred at room temperature for 2 h; after the reaction was completed, the coated iron powder was obtained by filtering and vacuum drying at 100°C.

[0042] (2) 10 g of the coated iron powder was placed in a pressing mold for pre-pressing and molding, and the molding pressure was 600 MPa and the pressure holding time was 30 s.

[0043] (3) The pre-pressing and molding magnetic core was placed in a vacuum sintering furnace and sintered at 200°C for 60 min.

[0044] (4) Take 10 g of emulsion containing 60% polytetrafluoroethylene, 5 g of calcium chloride and 1000 g of deionized water, mix well and dissolve, prepare reaction liquid B; take the preformed magnetic core as the anode, take the stainless steel plate as the cathode, take the reaction liquid B as the electrolyte for electrophoresis treatment, the treatment voltage is 90V, the treatment time is 20s, the gas pressure in the electrolytic tank is-0.07MPa; after electrophoresis, the magnetic core is dried, the temperature is 200℃, the time is 10min.

[0045] (5) Put the magnetic core after electrophoretic hole sealing into the mold, use 1200MPa pressure to press for 20s.

[0046] (6) Put 10g of perfluorodecyltrimethoxysilane into 200g of isopropyl alcohol, mix well, prepare reaction liquid C; soak the high-pressure formed magnetic core in reaction liquid C for 30s; finally, dry and heat treat, the heat treatment temperature is 150℃, the time is 20min, to obtain a soft magnetic core.

[0047] Example 4

[0048] (1) Put 10g of KH550 and 1g of nano titanium dioxide particles into 1000g of isopropyl alcohol, stir uniformly, then use ultrasonic dispersion for 60min, prepare reaction liquid A; put 100g of carbonyl iron powder into 500g of reaction liquid A, stir at room temperature for 2h; after the reaction is completed, filter and vacuum dry at 100℃ to obtain coated iron powder.

[0049] (2) Take 10g of coated iron powder, put it into a pressing mold, and perform pre-pressing forming, the forming pressure is 600MPa, and the pressure holding time is 30s.

[0050] (3) Sinter the pre-pressing formed magnetic core under inert gas protection, sinter at 300℃ for 30min, the inert gas used is nitrogen.

[0051] (4) Take 10 g of emulsion containing 60% polytetrafluoroethylene, 5 g of calcium chloride and 1000 g of deionized water, mix well and dissolve, prepare reaction liquid B; take the preformed magnetic core as the anode, take the stainless steel plate as the cathode, take the reaction liquid B as the electrolyte for electrophoresis treatment, the treatment voltage is 90V, the treatment time is 20s, the gas pressure in the electrolytic tank is-0.09MPa; after electrophoresis, the magnetic core is dried, the temperature is 160℃, the time is 20min.

[0052] (5) Put the magnetic core after electrophoretic hole sealing into the mold, use 1200MPa pressure to press for 20s.

[0053] (6) 10 g of perfluorooctyltriethoxysilane was added to 200 g of isopropyl alcohol and stirred until mixed evenly to prepare reaction liquid C. The high-pressure formed magnetic core was soaked in the reaction liquid C for 30 s. Finally, drying and heat treatment were performed, the heat treatment temperature was 150°C, and the time was 20 min to obtain the soft magnetic core.

[0054] Example 5

[0055] (1) 5 g of KH550 and 5 g of KH560 were mixed, and the obtained mixture and 1 g of nano-silica particles were added to 1000 g of isopropyl alcohol. After stirring evenly, ultrasonic dispersion was performed for 60 min to prepare reaction liquid A. 100 g of iron-silicon-aluminum powder was added to 500 g of reaction liquid A, and stirred at room temperature for 2 h. After the reaction was completed, the coated iron powder was obtained by filtration and vacuum drying at 100°C.

[0056] (2) 10 g of the coated iron powder was placed in a pressing mold and pre-pressed to form a magnetic core, the forming pressure was 600 MPa, and the pressure holding time was 30 s.

[0057] (3) The pre-pressed magnetic core was placed in a vacuum sintering furnace and sintered at 300°C for 30 min.

[0058] (4) 10 g of perfluorooctyltriethoxysilane, 5 g of magnesium chloride, and 1000 g of deionized water were mixed and stirred until dissolved to prepare reaction liquid B. The pre-formed magnetic core was used as the anode, a stainless steel plate was used as the cathode, and reaction liquid B was used as the electrolyte for electrophoresis treatment. The treatment voltage was 90 V, the treatment time was 20 s, and the gas pressure in the electrolytic cell was -0.07 MPa. After electrophoresis, the magnetic core was dried at a temperature of 160°C for 20 min.

[0059] (5) The magnetic core after electrophoretic hole sealing was placed in a mold and pressed using a pressure of 1200 MPa for 20 s.

[0060] (6) 10 g of perfluorooctyltriethoxysilane was added to 200 g of isopropyl alcohol and stirred until mixed evenly to prepare reaction liquid C. The high-pressure formed magnetic core was soaked in the reaction liquid C for 30 s. Finally, drying and heat treatment were performed, the heat treatment temperature was 150°C, and the time was 20 min to obtain the soft magnetic core.

[0061] Example 6

[0062] (1) 10 g of KH570 and 1 g of nano-silica particles were added to 1000 g of anhydrous ethanol, stirred uniformly, and then dispersed using ultrasonic for 60 min to prepare a reaction solution A; 50 g of iron-silicon-aluminum powder and 50 g of iron-silicon powder were mixed and then added to 500 g of the reaction solution A, and stirred at room temperature for 2 h; after the reaction was completed, the product was filtered and dried at 100°C under vacuum to obtain the coated iron powder.

[0063] (2) 10 g of the coated iron powder was placed in a pressing mold and pre-pressed to form a shaped core at a pressure of 600 MPa for 30 s.

[0064] (3) The pre-pressed core was placed in a vacuum sintering furnace and sintered at 300°C for 30 min.

[0065] (4) 10 g of perfluorodecyltrimethoxysilane, 5 g of calcium chloride and 1000 g of deionized water were mixed, stirred until dissolved, and a reaction solution B was prepared; the pre-formed core was used as the anode, a stainless steel plate was used as the cathode, and the reaction solution B was used as the electrolyte for electrophoresis treatment, the treatment voltage was 90 V, the treatment time was 20 s, and the gas pressure in the electrolytic cell was -0.07 MPa; after the electrophoresis was completed, the core was dried at a temperature of 160°C for 20 min.

[0066] (5) The core after electrophoresis and hole sealing was placed in a mold and pressed at a pressure of 1200 MPa for 20 s.

[0067] (6) 5 g of perfluorodecyltrimethoxysilane and 5 g of perfluorooctyltriethoxysilane were added to 200 g of isopropyl alcohol, stirred until mixed uniformly, and a reaction solution C was prepared; the high-pressure formed core was soaked in the reaction solution C for 30 s; finally, drying and heat treatment were performed at a temperature of 150°C for 20 min to obtain a soft magnetic core.

[0068] Comparative Example 1

[0069] (1) Nano-silica coated iron powder was prepared: 20, 50, 30, 1, 10 and 20 parts of pure iron powder, anhydrous ethanol, deionized water, silane coupling agent, tetraethyl orthosilicate and ammonia were mixed, and stirred at room temperature for 3 h; after the reaction was completed, the precipitate was filtered, washed and dried to obtain the nano-silica coated iron powder.

[0070] (2) Magnetic powder raw material preparation: 10 g of the coated iron powder and 0.1 g of nano-graphite particles were mixed and stirred until uniformly mixed.

[0071] (3) Core pressing: the magnetic powder was placed in a mold and pressed at a pressure of 1000 MPa for 30 s to obtain a shaped core.

[0072] (4) Magnetic heat treatment: the pressed magnetic core is placed in a vacuum sintering furnace, sintered at 600℃ for 1h, and the finished product magnetic core is obtained.

[0073] The water contact angle of the surface of the magnetic core prepared in Examples 1-3 was tested according to GB / T 30693-2014; the neutral salt spray test was performed on the magnetic cores prepared in Examples 1-6 and the comparative example according to GB / T 10125-2021, and the time when the first rust spot appeared on the surface of the magnetic core was recorded. The test results are shown in Table 1:

[0074] Table 1 Water contact angle and neutral salt spray test results of Examples 1-6 and the comparative example

[0075]

[0076] From the water contact angle and neutral salt spray test data of Examples 1-6 above, it can be seen that the method of the present application can effectively improve the water contact angle of the surface of the magnetic core (the water contact angle is greater than 90°, which indicates that the soft magnetic core obtained in Examples 1-6 has hydrophobic properties), and the hydrophobic properties can make the salt spray droplets on the surface of the magnetic core spherical, reducing the contact time of the salt spray droplets with the surface of the magnetic core, and thus greatly improving the salt spray resistance of the magnetic core prepared in Examples 1-6.

[0077] The above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1.A soft magnetic composite material and a preparation method of a corrosion-resistant magnetic core thereof, characterized by comprising the following steps: S1, mixing a silane coupling agent, a nano-oxide and an organic solvent to prepare a reaction liquid A; adding iron powder into the reaction liquid A and continuously stirring to obtain coated iron powder by filtering and vacuum drying the reaction precipitate; S2, pressing the coated iron powder to obtain a pre-pressed magnetic core; S3, pre-sintering the pre-pressed magnetic core; S4, mixing fluoride, a divalent metal salt and deionized water to prepare a reaction liquid B; performing electrophoretic sealing on the pre-formed magnetic core as an anode with the reaction liquid B as an electrolyte, and then drying; S5, placing the magnetic core after electrophoretic sealing obtained in step S4 into a mold for high-pressure forming to obtain a high-pressure formed magnetic core; and S6, mixing fluoride and isopropyl alcohol to prepare a reaction liquid C, immersing the high-pressure formed magnetic core in the reaction liquid C, and then drying and heat treating. The iron powder in step S1 is one or a mixture of different particle sizes of one or more of pure iron powder, carbonyl iron powder, iron-silicon powder and iron-silicon-aluminum powder. The mass ratio of the silane coupling agent, the nano-oxide and the organic solvent in step S1 is 1:0.01-0.1:50-100, and the mixing method is ultrasonic dispersion at room temperature for 30-60 min. The silane coupling agent is a mixture of one or more of KH550, KH560 and KH570. The nano-oxide is a mixture of one or both of nano-SiO2 and nano-TiO2. The organic solvent is one of anhydrous ethanol and isopropyl alcohol. The mass ratio of the iron powder to the reaction liquid A in step S1 is 1:1-5, the reaction time is 2-4 h, and the drying temperature is 60-100℃. The pressure for pressing in step S2 is 300-600 MPa, and the pressure holding time is 30-90 s. The pre-sintering in step S3 is vacuum sintering or inert gas protection sintering, the pre-sintering temperature is 200-300℃, and the pre-sintering time is 30-60 min. The inert gas for inert gas protection sintering is nitrogen. The fluoride in step S4 is a mixture of one or more of 60% polytetrafluoroethylene emulsion, perfluorodecyltrimethoxysilane and perfluorooctyltriethoxysilane, the divalent metal salt is a calcium salt or a magnesium salt, the mass ratio of the fluoride, the divalent metal salt and the solvent water is 1:0.1-0.5:50-100, the electrophoretic sealing is performed by using a stainless steel plate as a cathode for electrophoretic treatment, the voltage is 60-90 V, the electrophoretic sealing reaction time is 20-40 s, the gas pressure in the electrolytic tank is ≤-0.07 MPa, and the drying temperature is 120-200℃ for 10-30 min. The pressure for high-pressure forming in step S5 is 900-1200 MPa, and the pressure holding time is 20-40 s. ​ ​ ​ ​ ​ ​ ​ 2. The soft magnetic composite material and the preparation method of the corrosion-resistant magnetic core thereof according to claim 1, characterized in that: ​ 3. The soft magnetic composite material and the preparation method of the corrosion-resistant magnetic core thereof according to claim 1, characterized in that: ​ 4. The soft magnetic composite material and the preparation method of the corrosion-resistant magnetic core thereof according to claims 1-3, characterized in that: ​ 5. The soft magnetic composite material and the corrosion-resistant magnetic core thereof according to claim 1, characterized in that: ​ 6. The soft magnetic composite material and the method for preparing the corrosion-resistant magnetic core thereof according to claim 1, characterized in that: ​ 7. The soft magnetic composite material and the corrosion-resistant magnetic core thereof according to claim 1, characterized in that: ​ 8. The soft magnetic composite material and the anticorrosive magnetic core thereof according to claim 1, characterized in that: ​ 9. The soft magnetic composite material and the corrosion-resistant magnetic core thereof according to claim 1, characterized in that: The fluoride of step S6 is a mixture of one or more of 60% polytetrafluoroethylene emulsion, perfluorodecyltrimethoxysilane, perfluorooctyltriethoxysilane, and the mass ratio of the fluoride and isopropyl alcohol is 1:10-20; the soaking reaction time of the high-pressure formed magnetic core in the reaction liquid C is 15-30s; the temperature of the heat treatment is 120-150℃, and the heat treatment time is 20-40min.

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