Preparation method of high-corrosion-resistance soft magnetic powder

Abstract

The invention relates to the technical field of powder metallurgy and magnetic materials, in particular to a preparation method of high-corrosion-resistance soft magnetic powder, which comprises the following steps: S1, preparing soft magnetic powder; s2, the soft magnetic powder is pretreated, and the pretreatment comprises oil removal, rust removal, coarsening and neutralization; s3, a plating solution is prepared, the soft magnetic powder treated in the step S2 is immersed in the plating solution, and a chromium plating layer is formed on the surface of the soft magnetic powder; s4, a bonding solution is prepared, the soft magnetic powder treated in the step S3 is fused with the bonding solution, the outer surface of the soft magnetic powder is coated with a bonding layer, the soft magnetic powder is pretreated and then subjected to chromium plating, the product appearance is improved, the corrosion resistance of the product is improved, the service life of an electronic component is prolonged, and a chromium plating layer has the following characteristics that the hardness is very high; the wear resistance is relatively high; good heat resistance is realized; the original gloss can be kept for a long time under the atmospheric condition; the catalyst has very high chemical stability in alkali, nitric acid, sulfide, carbonate and most of gases and organic acids, and is suitable for electromagnetic equipment; and the chromium layer is bright, and the product appearance can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical fields of powder metallurgy and magnetic materials, and particularly relates to a method for preparing highly corrosion-resistant soft magnetic powder. Background Art

[0002] In recent years, electronic communication and intelligent electronic products have developed rapidly. With the popularization of big data analysis and 5G communication devices, the processing frequency of information is getting higher and higher. From the literature retrieval in the past decade, it can be seen that the working frequency of electronic communication devices has developed from several hundred KHz to dozens of MHz, and the processing frequency in big data processing devices, 5G communication devices and military electronic equipment can reach more than 100 MHz. Inductors are indispensable electromagnetic components in the circuits of computers and various information processing electronic devices.

[0003] Fe-based magnetic materials are widely used in the manufacture of inductors due to their advantages of high magnetic induction intensity and low coercive force. Due to the popularization of various information processing devices, such as computers, laptops, tablets, smartphones, automotive electronics, wireless charging and electric vehicle charging piles, the application and manufacturing quantity of inductors are beyond imagination. However, due to the volume limitation of these electronic devices, inductors are required to be miniaturized and high-frequency, so surface mount device (SMD) inductors have become the main application inductors. No matter what shape the SMD inductors are, there are basically two manufacturing methods: in-mold molding (MoldingType) with the coil embedded and sintering molding (NRType) with the coil wound outside. No matter what manufacturing process is used, the Fe-based soft magnetic powder must be insulated. The significance of insulation treatment is to minimize the charge concentration on the surface of powder particles under high-frequency alternating electromagnetic fields, and to avoid the conduction (regarded as short circuit) of eddy currents generated inside the powder particles between the powder particles under high-frequency electromagnetic fields as much as possible. Otherwise, the inductor will generate large power losses, heat and even burn out the circuit. In addition, it is also necessary to avoid the inductor being broken down under instantaneous high voltage, which may cause damage to the entire device.

[0004] In recent years, due to the strict control of power losses at high frequencies in big data analysis, 5G communication devices, new generation solid-state memory SSDs and ultra-high-frequency CPU integrated circuits, Fe-based amorphous powders, such as Fe-Si-B-C, and Fe-based nanocrystals, such as Fe-Si-B-Cu-Nb (Finemet), etc., have been gradually taken seriously and have been used to manufacture new inductors with low losses. The main types of Fe-based soft magnetic powders are: pure iron powder, Fe-Si, Fe-Si-Cr, Fe-Ni (Permalloy), Fe-Ni-Mo (MPP), Fe-Co, Fe-Si-Al (Sendust), etc.

[0005] At present, the insulation layer preparation technologies for various Fe-based soft magnetic powders are mainly divided into inorganic coating insulation and organic coating insulation. In inorganic coating insulation, phosphating treatment is the simplest and most widely used method. Its principle is to dissolve phosphoric acid in volatile organic solvents (such as acetone, alcohol, etc.), mix and stir it with Fe-based soft magnetic powders. After giving sufficient reaction time, PO43- forms an ionic bond with Fe2+ on the surface of Fe-based soft magnetic powder particles, thereby forming a dense inorganic phosphoric acid coating layer. This phosphoric acid coating layer has a certain insulation effect. However, the disadvantages of inorganic phosphoric acid coating are as follows: if the amount of phosphoric acid is too small, the chemical reaction between phosphoric acid and powder particles will be insufficient, the insulation layer will be too thin, or some parts will not be coated with phosphoric acid, reducing the resistivity of the inductor. If the amount of phosphoric acid added is too much, the magnetic permeability of the inductor will decrease too much, failing to meet the usage requirements.

[0006] Phosphoric acid is a strong acid, and the powder after phosphoric acid coating is acidic. After the insulation treatment of Fe-based soft magnetic powders, glue coating is still required, that is, using glue as an adhesive to make the inductor after powder pressing have the required shape, size and strength.

[0007] Generally, organic resins such as epoxy resin and phenolic resin are used as glue. Organic resins are generally alkaline, so the phosphoric acid layer will damage the glue, resulting in cracks in the inductor and deterioration of the environmental corrosion resistance.

[0008] The insulation effect of the phosphoric acid coating layer has a limit and is easily broken down at a voltage of 500 - 600V.

[0009] In summary, it is difficult to control the quality of the phosphoric acid coating insulation layer, and the withstand voltage value has a limit. Therefore, phosphoric acid coating is not the best insulation layer preparation process for Fe-based soft magnetic powders. The phosphoric acid coating insulation layer cannot meet the requirements of the increasingly high information processing frequency.

[0010] The organic coating insulation layer uses organic solvents such as epoxy resin, phenolic resin, or silicone resin to coat the surface of the particles, and forms an organic matter-coated insulation layer after heating and drying. The biggest disadvantage of organic coating is that the binding force between the organic matter and the surface of Fe-based soft magnetic powder particles is weak, and the coating layer is easily damaged, thus reducing the insulation effect. And the organic coating layer is not resistant to aging and has the problem of low lifespan.

[0011] Furthermore, whether it is the phosphoric acid coating layer or the organic coating insulation layer, they both occupy a part of the volume of the inductor, and a part of the inductance value characteristics needs to be sacrificed, resulting in the need to improve the inductance value of the inductor. Therefore, a preparation method of high-corrosion-resistant soft magnetic powder is needed to solve the above problems. Summary of the Invention

[0012] To solve the above technical problems, the present invention provides a preparation method of high-corrosion-resistant soft magnetic powder to solve the problems in the existing market mentioned in the above background technology.

[0013] To achieve the above object, the technical solution of the present invention is as follows:

[0014] A preparation method of a highly corrosion-resistant soft magnetic powder, comprising:

[0015] S1. Prepare soft magnetic powder;

[0016] S2. Pretreat the soft magnetic powder, including degreasing, derusting, roughening, and neutralizing;

[0017] S3. Prepare a plating solution, and immerse the soft magnetic powder treated in step S2 into the plating solution to form a chromium plating layer on the surface of the soft magnetic powder;

[0018] S4. Prepare a bonding solution, and fuse the soft magnetic powder treated in step S3 with the bonding solution to coat a bonding layer on the outer surface of the soft magnetic powder.

[0019] Through the above technical solution, by pretreating the soft magnetic powder and then chromium plating, the appearance of the product is improved, the corrosion resistance of the product is enhanced, the service life of electronic components is prolonged, and the chromium plating layer has the following characteristics: very high hardness; relatively high wear resistance; very good heat resistance; can maintain the original luster for a long time under atmospheric conditions; has very high chemical stability in alkalis, nitric acid, sulfides, carbonates, and most gases and organic acids. The formed product after chromium plating of the soft magnetic powder has better: corrosion resistance: the chromium layer can effectively prevent the ferromagnetic powder from oxidation and corrosion; wear resistance: the chromium layer has high hardness, can enhance wear resistance and prolong the service life; magnetic property improvement: chromium plating can optimize the magnetic properties of the ferromagnetic powder and is applicable to electromagnetic devices; appearance improvement: the chromium layer is bright and can improve the appearance of the product.

[0020] As a preferred solution of the present invention, the degreasing in step S2 further includes the following steps:

[0021] S211. Prepare a degreasing solution, including an organic solvent or an alkaline cleaning agent, a surfactant, and a cleaning solution;

[0022] S212. The alkaline cleaning agent is sodium hydroxide, the surfactant is stearic acid, and the ratio of sodium hydroxide, stearic acid, and water is 1:5:9;

[0023] S213. Immerse the soft magnetic powder in the degreasing solution for 10 minutes;

[0024] S214. Wash the soft magnetic powder with the cleaning solution.

[0025] Through the above technical solution, the main purpose of powder degreasing is to improve the surface brightness, remove surface grease and various corrosion products such as oxide scales.

[0026] As a preferred solution of the present invention, the derusting in step S2 further includes the following steps:

[0027] S221. Prepare a rust removal solution, including concentrated hydrochloric acid and water, where the ratio of concentrated hydrochloric acid to water is 1:1;

[0028] S222. Immerse the soft magnetic powder in step S214 in the rust removal solution for 10 minutes;

[0029] S223. Wash the soft magnetic powder with a cleaning solution until it is neutral.

[0030] Through the above technical solution, prepare a solution of concentrated hydrochloric acid plus an equal amount of cleaning solution to remove rust on the surface of the powder,

[0031] and then wash the powder with a cleaning solution until it is neutral.

[0032] As a preferred solution of the present invention, the roughening in step S2 further includes the following steps:

[0033] S231. Prepare a roughening solution, including 30 g / L of chromium trioxide, 60 g / L of concentrated sulfuric acid, and 1 L of water;

[0034] S232. Immerse the soft magnetic powder in step S223 in the roughening solution for 10 minutes;

[0035] S233. Wash the soft magnetic powder with a cleaning solution.

[0036] Through the above technical solution, the purpose of the roughening treatment is to make the metal surface have a certain roughness to ensure a good bonding force between the metal coating and the powder surface.

[0037] As a preferred solution of the present invention, the neutralization in step S2 further includes the following steps:

[0038] S241. Prepare a neutralization solution, including 10 g / L of sodium hydroxide and 1 L of water;

[0039] S242. Immerse the soft magnetic powder in step S233 in the neutralization solution for 5 minutes;

[0040] S243. Wash the soft magnetic powder with a cleaning solution and dry it at a temperature of 120 °C for 1 h.

[0041] Through the above technical solution, the purpose of neutralization is to balance the pH value of the metal surface. Neutralization is completed by an alkaline solution.

[0042] As a preferred solution of the present invention, step S3 further includes the following steps:

[0043] S31. Prepare a chromium plating solution, including 30 - 50 g / L of chromium trichloride, 30 - 50 g / L of sodium hypophosphite, 20 - 40 g / L of potassium sodium tartrate, 1 - 20 g / L of boric acid, 1 - 10 g / L of polyvinylpyrrolidone, and 0.01 - 10 g / L of thiourea;

[0044] S32. Heat the chromium plating solution to 70 °C, and immerse the dried soft magnetic powder in step S243 into the chromium plating solution for 1 h;

[0045] S33. After taking out the soft magnetic powder in step S32, wash it with a cleaning solution;

[0046] S34. Put it in a drying oven and dry it at 120 °C for 1 h, so that the outer surface of the soft magnetic powder is coated with a chromium plating layer.

[0047] Through the above technical solution, the treated powder is immersed in the chromium plating solution. The trivalent chromium ions contained in the chromium plating solution are deposited on the surface of the powder under the action of a reducing agent to form a core-shell structure; after chromium plating is completed, the powder is taken out, washed with a cleaning solution, and then dried in an oven.

[0048] As a preferred solution of the present invention, step S4 further includes the following steps:

[0049] S41. Prepare a bonding solution by dissolving a two-component thermosetting resin with a mass ratio of 2% - 5% to the alloy powder in a 10% - 20% acetone solution to form a bonding solution, and stir the bonding solution with the soft magnetic powder with a chromium plating layer in step S34 at 25 ± 5 °C for 0.5 - 2 h to form a preliminary mixture;

[0050] S42. Remove the volatile acetone in the preliminary mixture in S41 through a vacuum pump;

[0051] S43. Bake the preliminary mixture after volatilization at 55 °C for 1 - 2 h to completely volatilize the acetone solvent, and cure the preliminary solution and coat it on the outer surface of the chromium plating layer to form a bonding layer.

[0052] Through the above technical solution, the main purpose of the bonding layer is to provide the bonding ability for the device to be pressed into shape.

[0053] As a preferred solution of the present invention, the soft magnetic powder material is a magnetic metal material.

[0054] A highly corrosion-resistant soft magnetic powder body, the soft magnetic powder includes:

[0055] Granulated powder, including soft magnetic powder particles with magnetic properties, a surfactant, and a dispersant;

[0056] Chromium plating layer, coated on the outer surface of the soft magnetic powder particle core;

[0057] Bonding layer, coated on the outer surface of the chromium plating layer.

[0058] A highly corrosion-resistant inductor, which is obtained by pressing an inductor powder.

[0059] Compared with the prior art, the beneficial effects of the present invention are:

[0060] By pre-treating the soft magnetic powder and then chromium plating, the product appearance is improved, the corrosion resistance of the product is enhanced, and the service life of electronic components is extended.

[0061] The chromium plating layer has the following characteristics: high hardness; high wear resistance; good heat resistance; can maintain the original luster for a long time under atmospheric conditions; has high chemical stability in alkalis, nitric acid, sulfides, carbonates, and most gases and organic acids.

[0062] Both the hysteresis loss and the total loss of the soft magnetic powder are relatively low, the magnetic permeability performance is improved, the inductance volume is reduced on the basis of ensuring the magnetic permeability, miniaturization and micro-miniaturization are achieved, and the overall performance of the product is enhanced.

[0063] The powder has good formability and is not easy to crack after forming.

[0064] The formed product after chromium plating of the soft magnetic powder has better:

[0065] Corrosion resistance: The chromium layer can effectively prevent the ferromagnetic powder from oxidation and corrosion.

[0066] Wear resistance: The chromium layer has high hardness, can enhance wear resistance and extend the service life.

[0067] Magnetic improvement: Chromium plating can optimize the magnetic properties of the ferromagnetic powder and is suitable for electromagnetic devices.

[0068] Appearance improvement: The chromium layer is bright and can improve the product appearance. Specific implementation manners

[0069] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0070] The present invention provides the following embodiments:

[0071] A preparation method of a high-corrosion-resistant soft magnetic powder, comprising:

[0072] S1. Prepare the soft magnetic powder;

[0073] S2. Pre-treat the soft magnetic powder, including degreasing, derusting, roughening, and neutralizing;

[0074] In step S2, the degreasing further includes the following steps:

[0075] S211. Prepare the degreasing solution, including organic solvents or alkaline cleaning agents, surfactants, and cleaning liquids;

[0076] S212. The alkaline cleaning agent is sodium hydroxide, and the surfactant is stearic acid. The ratio of sodium hydroxide, stearic acid, and water is 1:5:9.

[0077] S213. Immerse the soft magnetic powder in the degreasing solution for 10 minutes.

[0078] S214. Wash the soft magnetic powder with the cleaning solution.

[0079] The main purpose of powder degreasing is to improve the surface brightness, remove surface grease, scale, and other corrosion products.

[0080] The rust removal in step S2 further includes the following steps:

[0081] S221. Prepare a rust removal solution, including concentrated hydrochloric acid and water. The ratio of concentrated hydrochloric acid to water is 1:1.

[0082] S222. Immerse the soft magnetic powder in step S214 in the rust removal solution for 10 minutes.

[0083] S223. Wash the soft magnetic powder with the cleaning solution until it is neutral.

[0084] Prepare a solution of concentrated hydrochloric acid plus an equal amount of cleaning solution to remove rust from the powder surface, and then wash the powder with the cleaning solution until it is neutral.

[0085] The roughening in step S2 further includes the following steps:

[0086] S231. Prepare a roughening solution, including 30 g / L of chromium trioxide, 60 g / L of concentrated sulfuric acid, and 1 L of water.

[0087] S232. Immerse the soft magnetic powder in step S223 in the roughening solution for 10 minutes.

[0088] S233. Wash the soft magnetic powder with the cleaning solution.

[0089] The purpose of roughening treatment is to make the metal surface have a certain roughness to ensure good adhesion between the metal coating and the powder surface.

[0090] The neutralization in step S2 further includes the following steps:

[0091] S241. Prepare a neutralization solution, including 10 g / L of sodium hydroxide and 1 L of water.

[0092] S242. Immerse the soft magnetic powder in step S233 in the neutralization solution for 5 minutes.

[0093] S243. Wash the soft magnetic powder with the cleaning solution and dry it at 120 °C for 1 h.

[0094] The purpose of neutralization is to balance the pH value of the metal surface. Neutralization is accomplished by an alkaline solution.

[0095] S3. Prepare the plating solution and immerse the soft magnetic powder treated in step S2 into the plating solution to form a chromium plating layer on the surface of the soft magnetic powder;

[0096] Step S3 further includes the following steps:

[0097] S31. Prepare the chromium plating solution, including 30 - 50 g / L of chromium trichloride, 30 - 50 g / L of sodium hypophosphite, 20 - 40 g / L of sodium potassium tartrate, 1 - 20 g / L of boric acid, 1 - 10 g / L of polyvinylpyrrolidone, 0.01 - 10 g / L of thiourea; Preferably: including 30 g / L of chromium trichloride, 28 g / L of sodium hypophosphite, 25 g / L of sodium potassium tartrate, 10 g / L of boric acid, 3 g / L of polyvinylpyrrolidone, 0.5 g / L of thiourea;

[0098] S32. Heat the chromium plating solution to 70 °C and immerse the dried soft magnetic powder in step S243 into the chromium plating solution for 1 h;

[0099] S33. After taking out the soft magnetic powder in step S32, wash it with the cleaning solution;

[0100] S34. Put it into a drying oven and dry it at 120 °C for 1 h so that the outer surface of the soft magnetic powder is coated with a chromium plating layer.

[0101] Immerse the treated powder in the chromium plating solution. The trivalent chromium ions contained in the chromium plating solution are deposited on the surface of the powder under the action of a reducing agent to form a core - shell structure; After chromium plating, take out the powder, wash it with the cleaning solution and then dry it in an oven.

[0102] S4. Prepare the binding solution and fuse the soft magnetic powder treated in step S3 with the binding solution to coat a binding layer on the outer surface of the soft magnetic powder.

[0103] Step S4 further includes the following steps:

[0104] S41. Prepare the binding solution, dissolve the two - component thermosetting resin with a mass ratio of 2% - 5% to the alloy powder in a 10% - 20% acetone solution to form the binding solution, and stir the binding solution and the soft magnetic powder with a chromium plating layer in step S34 at 25 ± 5 °C for 0.5 - 2 h to form a preliminary mixture;

[0105] S42. Remove the volatile acetone in the preliminary mixture in S41 through a vacuum pump;

[0106] S43. Bake the preliminary mixture after volatilization at 55 °C for 1 - 2 h to completely volatilize the acetone solvent, and cure the preliminary solution and coat it on the outer surface of the chromium plating layer to form a binding layer.

[0107] The main purpose of the bonding layer is to provide the bonding ability for the device to be pressed into shape.

[0108] Preferably, during the above degreasing, derusting, roughening, neutralizing, and chromium plating processes, mechanical stirring is used to make the reaction proceed uniformly and fully, and ultrasonic dispersion of the soft magnetic powder is used. This increases the contact area between the soft magnetic powder and the solution, and avoids uneven reaction caused by powder adhesion.

[0109] Preferably, during the process of adding the soft magnetic powder to the above bonding solution, mechanical stirring is used to make the stirring uniform.

[0110] As a preferred embodiment of the present invention, the soft magnetic powder material is a magnetic metal material.

[0111] Preferably, the cleaning liquid is water, and preferably the cleaning liquid is distilled water.

[0112] A highly corrosion-resistant soft magnetic powder, the soft magnetic powder includes:

[0113] Granulated powder, including soft magnetic powder particles with magnetic properties, a surfactant, and a dispersant;

[0114] Chromium plating layer, covering the outer surface of the soft magnetic powder particles;

[0115] Bonding layer, covering the outer surface of the chromium plating layer.

[0116] A highly corrosion-resistant inductor, made by pressing an inductor powder.

[0117] The metal plating layer on the powder can endow the powder with different new special functions, such as inhibiting powder decomposition, improving the corrosion resistance of the powder, giving the powder conductivity, and endowing the powder with a smoother appearance. Using the electroless plating process to coat the metal soft magnetic powder can achieve better wear resistance and corrosion protection effects on the product when applied to the forming of electronic components, without the need for additional protection of the finished product appearance. For the soft magnetic powder directly used in the forming of electronic components without electroless plating, a protective coating is often required on the surface of the device after forming to play the role of moisture-proof, salt spray-proof, and mildew-proof. Therefore, the powder after electroless plating can save the spraying process after forming, save materials, reduce energy consumption, and improve production efficiency.

[0118] By pre-treating the soft magnetic powder and then chromium plating, the appearance of the product is improved, the corrosion resistance of the product is enhanced, and the service life of electronic components is extended. The chromium plating layer has the following characteristics: high hardness, high wear resistance, good heat resistance, can maintain the original luster for a long time under atmospheric conditions, and has high chemical stability in alkalis, nitric acid, sulfides, carbonates, and most gases and organic acids. The formed products after chromium plating of the soft magnetic powder have better: corrosion resistance: the chromium layer can effectively prevent the ferromagnetic powder from oxidation and corrosion; wear resistance: the chromium layer has high hardness, which can enhance wear resistance and extend the service life; magnetic improvement: chromium plating can optimize the magnetic properties of the ferromagnetic powder and is applicable to electromagnetic devices; appearance improvement: the chromium layer is bright, which can improve the appearance of the product, reduce the complex production processes and techniques, and can better serve and explore the market.

[0119] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a highly corrosion-resistant soft magnetic powder, characterized in that ,include: S1. Prepare soft magnetic powder; S2, pre-treating the soft magnetic powder, including degreasing, derusting, coarsening, and neutralization; S3, preparing a plating solution, and immersing the soft magnetic powder treated in step S2 into the plating solution to form a chrome plating layer on the surface of the soft magnetic powder; S4, preparing a bonding solution, fusing the soft magnetic powder treated in step S3 with the bonding solution, and coating the outer surface of the soft magnetic powder with a bonding layer.

2. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: The degreasing in step S2 also includes the following steps: S211, preparing a degreasing solution, including an organic solvent or an alkaline cleaning agent, a surfactant, and a cleaning liquid; S212, the alkaline cleaning agent is sodium hydroxide, the surfactant is stearic acid, wherein the ratio of sodium hydroxide, stearic acid and water is 1:5:9; S213, soaking the soft magnetic powder in the degreasing solution for 10 minutes; S214, washing the soft magnetic powder with a cleaning solution.

3. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: In step S2, the rust removal further comprises the following steps: S221, preparing a rust removal solution, including concentrated hydrochloric acid and water, wherein the ratio of concentrated hydrochloric acid to water is 1:1; S222, soaking the soft magnetic powder in step S214 in a rust removal solution for 10 minutes; S223, washing the soft magnetic powder with a cleaning solution until it becomes neutral.

4. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: The roughening in step S2 further includes the following steps: S231, prepare a roughening solution, including 30 g / L chromium trioxide, 60 g / L concentrated sulfuric acid, and 1 L of water; S232, soaking the soft magnetic powder in step S223 in the roughening liquid for 10 minutes; S233, washing the soft magnetic powder with a cleaning solution.

5. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: The neutralization in step S2 further comprises the following steps: S241, prepare a neutralization solution, including 10 g / L sodium hydroxide and 1 L water; S242, soaking the soft magnetic powder in step S233 in the neutralization solution for 5 minutes; S243, wash the soft magnetic powder with a cleaning solution and dry it at 120°C for 1 hour.

6. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: Step S3 also includes the following steps: S31, prepare a chrome plating solution, including 30-50 g / L chromium trichloride, 30-50 g / L sodium hypophosphite, 20-40 g / L potassium sodium tartrate, 1-20 g / L boric acid, 1-10 g / L polyvinyl pyrrolidone, and 0.01-10 g / L thiourea; S32, heating the chrome plating solution to 70-100°C, and soaking the soft magnetic powder dried in step S243 in the chrome plating solution for 1-2 hours; S33, taking out the soft magnetic powder in step S32 and washing it with a cleaning solution; S34, placing the soft magnetic powder in step S33 into a drying oven at 120°C for 1 hour, so that the outer surface of the soft magnetic powder is coated with a chrome plating layer.

7. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: Step S4 also includes the following steps: S41, a bonding solution comprises dissolving a two-component thermosetting resin having a mass ratio of 2% to 5% to the alloy powder in a 10% to 20% acetone solution to form a bonding solution, and stirring the bonding solution and the soft magnetic powder having a chrome-plated layer in step S34 at 25±5° C. for 0.5 to 2 hours to form a preliminary mixture; S42, removing volatile acetone from the preliminary mixture in S41 by a vacuum pump; S43, baking the volatilized preliminary mixture at 55° C. for 1 to 2 hours to completely volatilize the acetone solvent, and solidifying the preliminary solution and coating the outer surface of the chrome-plated layer to form a bonding layer.

8. The method for preparing a highly corrosion-resistant soft magnetic powder according to claim 1, characterized in that: Soft magnetic powder is made of magnetic metal material.

9. A highly corrosion-resistant soft magnetic powder, prepared by the method for preparing a highly corrosion-resistant soft magnetic powder according to any one of claims 1 to 8, characterized in that: Soft magnetic powders include: Granulated powder, including soft magnetic powder particle core with magnetic properties, surfactant, and dispersant; A chrome-plated layer is coated on the outer surface of the soft magnetic powder particle core; The bonding layer is coated on the outer surface of the chrome-plated layer.

10. A highly corrosion-resistant inductor, characterized in that: The inductor powder according to claim 9 is obtained by molding.