Soft magnetic metal material, and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of magnetic functional materials, and specifically relates to a soft magnetic metal material, and a preparation method therefor and a use thereof. The soft magnetic metal material comprises soft magnetic metal raw powder and an insulating layer that coats the surface of the soft magnetic metal raw powder; in the radial direction of the soft magnetic metal material, the insulating layer sequentially comprises, from inside to outside, a phosphating layer, an inorganic fine powder layer, and a silicone resin layer. In the soft magnetic metal material of the present invention, by means of coordination of the phosphating layer, the inorganic fine powder layer, and the silicone resin layer, the soft magnetic metal material has properties such as high heat resistance, high stability, high strength, and low loss. The soft magnetic metal material is uniform, dense, and reliable, and also has good high-temperature environmental stability under harsh environmental conditions such as high temperature and high humidity. Even after long-term use, deterioration and failure of magnetic permeability characteristics and inductance characteristics of a magnetic core can be prevented.

Description

A soft magnetic metallic material, its preparation method and application

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 2025100749032, filed on January 16, 2025, entitled “A soft magnetic metal material and its preparation method and application”, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to the field of magnetic functional materials technology, specifically to a soft magnetic metal material, its preparation method, and its application. Background Technology

[0004] Magnetic powder cores typically employ an insulating coating layer formed on the powder surface to reduce eddy current losses. Organic insulating layers (such as epoxy resin) possess good adhesion and flexibility, but their high-temperature stability is poor, gradually decomposing with increasing annealing temperature or heating time. Inorganic insulating layers (such as SiO2) have high resistivity and good thermal stability, but relying solely on physical coating methods like stirring makes it difficult to uniformly coat SiO2 particles onto the soft magnetic metal surface. The phosphate passivation method, widely used in magnetic powder cores, relies solely on diphosphates such as iron phosphate formed through phosphoric acid corrosion. Due to their porosity and poor thermal stability, it is difficult to form a dense insulating layer with high resistivity. Furthermore, to prevent the insulating coating layer from decomposing and deteriorating during annealing, the annealing temperature is often set too low. This typically results in soft magnetic materials with lower strength, failing to meet the harsh conditions of applications such as new energy vehicles and photovoltaics. Summary of the Invention

[0005] This invention provides a soft magnetic metal material, its preparation method, and its application, in order to solve the problems of poor thermal stability, difficulty in forming a dense insulating layer with high resistivity, and low strength of existing soft magnetic metal materials.

[0006] According to a first aspect of the present invention, the present invention provides a soft magnetic metal material, comprising soft magnetic metal powder and an insulating layer coating the surface of the soft magnetic metal powder; along the radial direction of the soft magnetic metal material from the inside to the outside, the insulating layer sequentially comprises a phosphate layer, an inorganic fine powder layer and a silicone resin layer.

[0007] Furthermore, the phosphating layer is formed by a phosphating reaction between the phosphating solution and the surface of the soft magnetic metal powder; the phosphating solution contains a phosphoric acid solution and a functional solute, the functional solute including one or more of aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, and sodium nitrite.

[0008] Furthermore, in the phosphating solution, the mass percentage of the functional solute is 0.5% to 20.0%.

[0009] Furthermore, the inorganic fine powder layer includes one or more of MnZn ferrite, iron(II,III) oxide, glass powder, and silicate powder.

[0010] Furthermore, the thickness of the insulating layer is 0.02–2 μm;

[0011] Preferably, the thickness of the phosphating layer is 50–200 nm; the thickness of the inorganic fine powder layer is 0.02–1.5 μm; and the thickness of the silicone resin layer is 0.02–1.5 μm.

[0012] Furthermore, the soft magnetic metal powder includes one or more of the following: Fe powder, Fe-Si powder, Fe-Si-Al powder, Fe-Si-Cr powder, Fe-Ni powder, Fe-Si-BC amorphous powder, Fe-Si-BCP amorphous powder, Fe-Cr-Si-BC amorphous powder, or Fe-Nb-Cu-Si-B nanocrystalline powder.

[0013] Furthermore, the average particle size D50 of the soft magnetic metal powder is 2–100 μm.

[0014] Furthermore, the silicone resin layer is formed of silicone resin, which includes a main component and auxiliary components. The main component includes heat-resistant silicone resin or silicone resin, and the auxiliary components include one or more of epoxy resin, phenolic resin and polyvinyl butyral.

[0015] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-described soft magnetic metallic material, comprising the following steps:

[0016] After uniformly mixing the soft magnetic metal raw powder and the inorganic fine powder, a mixed powder is obtained. The mixed powder is first sprayed with a phosphating solution. The phosphating solution reacts with the surface of the soft magnetic metal raw powder but does not react with the inorganic fine powder, so as to form a phosphating coating layer and an inorganic fine powder coating layer on the surface of the soft magnetic metal raw powder in sequence.

[0017] Then, silicone resin is used for coating to form a silicone resin coating layer on the inorganic fine powder coating layer;

[0018] Then, after granulation, drying, and sieving, lubricant is added and the mixture is pressed into shape.

[0019] Finally, annealing heat treatment is performed to obtain soft magnetic metal material.

[0020] Furthermore, the amount of the inorganic fine powder is 0.3% to 2.0% of the mass of the mixed powder;

[0021] Furthermore, the phosphating solution is used in an amount of 0.05% to 5.0% of the mass of the mixed powder;

[0022] Furthermore, the phosphating temperature is 25°C to 100°C;

[0023] Furthermore, the pressing pressure is 500MPa to 2300MPa; the pressing method is room temperature pressing.

[0024] Furthermore, the annealing heat treatment temperature is 600℃~800℃; the annealing heat treatment is carried out under an inert gas atmosphere. The inert gas includes nitrogen or argon, etc.

[0025] According to a third aspect of the present invention, the present invention also provides the application of the above-described soft magnetic metal material or the soft magnetic metal material prepared by the above-described preparation method in inductor elements. The inductor elements include power inductors and filter inductors, etc.

[0026] The present invention provides a soft magnetic metal material comprising metal powder and an insulating layer coated on the surface of the metal powder. The insulating layer comprises a phosphating layer, an inorganic fine powder layer, and a silicone resin layer. The three insulating coating layers of the soft magnetic metal material of the present invention work together to give the soft magnetic metal material high heat resistance, high stability, high strength, and low loss. It is not only uniform, dense, and reliable, but also has good high-temperature environmental stability under harsh environmental conditions such as high temperature and high humidity. Even after long-term use, it can prevent the magnetic permeability and inductance characteristics of the magnetic core from deteriorating and failing. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 is a schematic diagram of the structure of a soft magnetic metal material provided in Experimental Example 1 of the present invention.

[0029] Figure 2 is one of the scanning electron microscope images of a soft magnetic metal material provided in Embodiment 1 of the present invention.

[0030] Figure 3 is a second scanning electron microscope image of a soft magnetic metal material provided in Embodiment 1 of the present invention.

[0031] Figure 4 is a third scanning electron microscope image of a soft magnetic metal material provided in Embodiment 1 of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0033] According to a first aspect of the present invention, the present invention provides a soft magnetic metal material, comprising soft magnetic metal powder and an insulating layer coating the surface of the soft magnetic metal powder; along the radial direction of the soft magnetic metal material from the inside to the outside, the insulating layer sequentially comprises a phosphate layer, an inorganic fine powder layer and a silicone resin layer.

[0034] The soft magnetic metal material of this invention comprises soft magnetic metal powder and an insulating layer coated on the surface of the soft magnetic metal powder. The insulating layer reduces eddy current losses. Further, the insulating layer comprises a phosphating layer, an inorganic fine powder layer, and a silicone resin layer. The phosphating layer is formed by phosphating the surface of the soft magnetic metal powder with a multi-component phosphating solution, exhibiting strong adhesion to the soft magnetic metal powder, good density, and high resistivity. Coating the phosphating layer with an inorganic fine powder layer not only improves the magnetic permeability characteristics of the soft magnetic metal material and reduces losses, but also significantly increases the strength of the soft magnetic metal material after heat treatment, improving its vibration resistance and high-temperature resistance. The silicone resin layer, as the outermost layer of the insulating layer, is itself an insulating material, further increasing the resistivity of the material, improving the insulation performance of the soft magnetic metal material, and reducing eddy current losses. The silicone resin layer also possesses high-temperature resistance, which can improve the thermal stability of soft magnetic metal materials, allowing them to maintain good magnetic properties even in high-temperature environments. The silicone resin layer can also improve the mechanical strength of soft magnetic metal materials, making them more durable during processing and use. Furthermore, the silicone resin layer provides additional protection, enhancing the corrosion resistance of soft magnetic metal materials, allowing them to maintain performance even in harsh environments. The three-layer insulating coating structure of the soft magnetic metal material in this invention, with its three layers working together, gives the soft magnetic metal material high heat resistance, high stability, high strength, and low loss. It is not only uniform, dense, and reliable, but also exhibits excellent high-temperature environmental stability under harsh conditions such as high temperature and high humidity. Even after prolonged use, it can prevent the degradation and failure of the magnetic permeability and inductance characteristics of the magnetic core.

[0035] Furthermore, the phosphating layer is formed by a phosphating reaction between a phosphating solution and the surface of the soft magnetic metal powder. The phosphating solution comprises a phosphoric acid solution and a functional solute, which includes one or more of aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, and sodium nitrite. By selecting appropriate types of functional solutes to form a specific phosphating solution, a good synergistic effect can be achieved with the surface of the metal powder, forming a thin, highly bonded phosphating coating layer in situ on the surface of the metal powder. This phosphating coating layer has high resistivity and can effectively reduce eddy current losses.

[0036] It should be noted that the main component of the phosphating solution is phosphoric acid solution, with the addition of one or more functional components selected from aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, and sodium nitrite. Aluminum dihydrogen phosphate can simultaneously provide phosphate and aluminum ions, acting as a catalyst to promote the phosphating reaction, improve phosphating efficiency, enhance the corrosion resistance of the phosphating film, and provide better protection in various environments. It can also improve the physical properties of the phosphating film, such as hardness, wear resistance, and adhesion, making it more suitable for practical applications. Strontium oxide and yttrium oxide improve the thermal stability of the material, boric acid helps the oxides dissolve in phosphoric acid, magnesium oxide increases the resistivity of the phosphating layer material, zinc oxide improves the corrosion resistance of the material, and sodium molybdate and sodium nitrite help form a dense phosphating layer.

[0037] Furthermore, in the phosphating solution, the mass percentage of the functional solute is 0.5% to 20.0%.

[0038] Optionally, the mass percentage of the functional solute can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20.0%, etc. Limiting the mass percentage of the functional solute in the phosphating solution to a reasonable range is more beneficial for improving the resistivity of the phosphating layer, enhancing insulation performance, and more effectively reducing eddy current losses.

[0039] According to some specific embodiments of the present invention, the phosphating solution contains 0.1-5.0% aluminum dihydrogen phosphate, 0.1-5.0% strontium oxide, 0.05-1.0% boric acid, 0.05-1.0% magnesium oxide, 0.05-1.0% zinc oxide, 0.1-5.0% yttrium oxide, 0.05-1.0% sodium molybdate, and 0.05-1.0% sodium nitrite, with the remainder being a phosphoric acid solution. In some specific embodiments, the mass concentration of the phosphoric acid solution is 80-90%.

[0040] Furthermore, the inorganic fine powder layer includes one or more of MnZn ferrite, iron(II,III) oxide, glass powder, and silicate powder.

[0041] The purpose of this invention is to coat the phosphate layer with an inorganic fine powder layer to further improve the resistivity and strength (cooked strength) of the heat-treated soft magnetic metal material. Soft magnetic metal materials generally require the insulating coating material to be non-magnetic; excessive addition can lead to a decrease in magnetic permeability and dilution of various magnetic properties. Therefore, the amount added must be controlled within necessary limits. The inorganic fine powders selected in this invention are oxides with magnetic properties, possessing both insulating and soft magnetic characteristics (with minimal decrease in magnetic permeability). When these inorganic fine powder particles are annealed in the range of 600℃ to 800℃, due to their reactivity with the surface of the soft magnetic metal powder or their liquid phase, the cooked strength of the soft magnetic material can be significantly improved. This further enhances the resistivity and strength of the soft magnetic metal material without affecting its magnetic permeability.

[0042] Furthermore, the thickness of the insulating layer is 0.02–2 μm. Limiting the thickness of the insulating layer to a reasonable range is more conducive to improving insulation capability and reducing eddy current losses.

[0043] Preferably, the thickness of the phosphating layer is 50–200 nm; the thickness of the inorganic fine powder layer is 0.02–1.5 μm; and the thickness of the silicone resin layer is 0.02–1.5 μm. By limiting the thicknesses of the phosphating layer, inorganic fine powder layer, and silicone resin layer in the insulating layer to a reasonable range, better synergistic effects between the layers are achieved, which is more conducive to improving the overall performance of the soft magnetic metal material.

[0044] Furthermore, the soft magnetic metal powder includes one or more of the following: Fe powder, Fe-Si powder, Fe-Si-Al powder, Fe-Si-Cr powder, Fe-Ni powder, Fe-Si-BC amorphous powder, Fe-Si-BCP amorphous powder, Fe-Cr-Si-BC amorphous powder, or Fe-Nb-Cu-Si-B nanocrystalline powder. By selecting a suitable type of soft magnetic metal powder and combining it with an insulating layer of a specific structure, a better synergistic effect is achieved between the soft magnetic metal powder and the insulating layer, which is more conducive to improving the overall performance of the soft magnetic metal material.

[0045] Furthermore, the average particle size D50 of the soft magnetic metal powder is 2–100 μm.

[0046] Furthermore, the silicone resin layer is formed of silicone resin, which includes a main component and auxiliary components. The main component includes heat-resistant silicone resin or silicone resin, and the auxiliary components include one or more of epoxy resin, phenolic resin, and polyvinyl butyral. By limiting the composition of the silicone resin layer, the overall performance of the soft magnetic metal material can be improved more effectively. Preferably, the weight ratio of the main component to the auxiliary component is (85-95):(5-15). In some specific embodiments, the weight ratio of the main component to the auxiliary component is 90:10.

[0047] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned soft magnetic metal material, comprising the following steps:

[0048] After uniformly mixing the soft magnetic metal raw powder and the inorganic fine powder, a mixed powder is obtained. The mixed powder is first sprayed with a phosphating solution. The phosphating solution reacts with the surface of the soft magnetic metal raw powder but does not react with the inorganic fine powder, so as to form a phosphating coating layer and an inorganic fine powder coating layer on the surface of the soft magnetic metal raw powder in sequence.

[0049] Then, silicone resin is used for coating to form a silicone resin coating layer on the inorganic fine powder coating layer;

[0050] Then, after granulation, drying, and sieving, lubricant is added and the mixture is pressed into shape.

[0051] Finally, annealing heat treatment is performed to obtain soft magnetic metal material.

[0052] The method for preparing soft magnetic metal materials according to this invention involves first uniformly mixing metal powder and inorganic fine powder to obtain a mixed powder. Then, the mixed powder is spray-phosphated using a phosphating solution. This facilitates the uniform distribution of inorganic fine powder among the particles of the soft magnetic metal powder and creates a continuous, uninterrupted process during the phosphating-silicone resin coating process, eliminating the need for an intermediate mixing step. After forming a phosphating coating layer and an inorganic fine powder coating layer on the surface of the metal powder, heat-resistant silicone resin is applied to form a silicone resin coating layer. Finally, the mixture is pressed, annealed, and heat-treated. This process causes the multi-component phosphating coating layer to undergo a series of glass transition reactions to form a multi-component phosphate glass-based phosphating layer. The inorganic fine powder coating layer then forms an inorganic fine powder layer, and the organic molecular chains in the silicone resin coating layer thermally decompose to form a silicone resin layer with an inorganic silicon-oxygen cross-linked structure. This method for preparing soft magnetic metal materials is simple, easy to implement, and low in cost, making it suitable for large-scale industrial mass production.

[0053] Furthermore, the amount of inorganic fine powder used is 0.3% to 2.0% of the mass of the mixed powder. By limiting the amount of inorganic fine powder within a reasonable range, it is beneficial to form an inorganic fine powder layer of ideal thickness, while not affecting the reaction between the phosphating solution and the surface of the metal powder.

[0054] Optionally, the amount of the inorganic fine powder can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2.0% of the mass of the mixed powder.

[0055] Furthermore, the amount of phosphating solution used is 0.6% to 5.0% of the mass of the mixed powder. By limiting the amount of phosphating solution to a reasonable range, it is beneficial to the reaction between the phosphating solution and the surface of the metal powder, thereby improving the phosphating efficiency and forming a dense and stable phosphating layer.

[0056] Optionally, the amount of phosphating solution used can be 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5.0% of the mass of the mixed powder.

[0057] Furthermore, the phosphating temperature is between 25°C and 100°C. By selecting a reasonable range of phosphating temperatures, it is beneficial to improve the efficiency of the phosphating process, thereby forming a dense and stable phosphating layer.

[0058] Furthermore, the pressing pressure is 500 MPa to 2300 MPa; the pressing method is room temperature pressing. By limiting the pressing pressure and method, it is beneficial to form a high-quality insulating layer.

[0059] Furthermore, the annealing heat treatment temperature is 600℃~800℃; the annealing heat treatment is carried out under inert gas atmosphere protection. By limiting the annealing heat treatment temperature and inert gas conditions, it is beneficial to form high-quality layers in the insulating layer. In some specific embodiments, the inert gas refers to nitrogen.

[0060] According to a third aspect of the present invention, the present invention also provides the application of the above-described soft magnetic metal material or the soft magnetic metal material prepared by the above-described preparation method in magnetic powder core inductor products.

[0061] Example 1

[0062] This embodiment provides a soft magnetic metal material, as shown in Figure 1, comprising soft magnetic metal powder and an insulating layer coating the surface of the soft magnetic metal powder. Along the radial direction of the soft magnetic metal material from the inside out, the insulating layer sequentially comprises a phosphate layer, an inorganic fine powder layer, and a silicone resin layer. The thickness of the insulating layer is approximately 2 μm; the thickness of the phosphate layer is approximately 120 nm; the thickness of the inorganic fine powder layer is approximately 1.5 μm; and the thickness of the silicone resin layer is approximately 0.5 μm.

[0063] Its preparation method includes the following steps:

[0064] (1) Soft magnetic metal material using Fe-9.6Si-5.4Al raw powder: 2000g of iron-silicon-aluminum raw powder with D50=25μm and 20g of MnZn ferrite powder with D50=5μm are mixed evenly for 30min to obtain mixed powder.

[0065] (2) Phosphating Coating: First, prepare a phosphating solution containing 5.0% by mass of functional solutes such as oxides (containing 1.0% aluminum dihydrogen phosphate, 1.2% strontium oxide, 0.3% boric acid, 0.5% magnesium oxide, 0.5% zinc oxide, 0.5% yttrium oxide, 0.5% sodium molybdate, 0.5% sodium nitrite, and the remainder being a reagent-grade 85% phosphoric acid aqueous solution). Weigh the functional solute powders according to the specified proportions and dissolve them sequentially in a phosphoric acid solution heated to 150°C. By uniformly stirring, the oxides of various functional solutes are uniformly dissolved in the heated phosphoric acid solution. Cool the solution to room temperature to obtain the transparent, precipitate-free phosphating solution of this invention. Then, add 2000g of the above mixed powder to a container equipped with blades and capable of rotating and stirring (at 150 rpm / min). While rotating and stirring, spray the above phosphating solution, which accounts for 1.0% of the weight of the mixed powder, evenly. After all the powder is added, stir for 10 minutes and phosphating is carried out at room temperature (25°C). Then, while stirring, heat to 150°C for drying. After the powder is completely dry, a phosphating coating layer and an inorganic fine powder coating layer will be formed sequentially on the surface of the metal powder to obtain a phosphating-coated powder.

[0066] (3) Silicone resin coating: Preparation of silicone resin coating solution: In ethyl acetate solution, dissolve 50% of heat-resistant silicone resin powder (including thermosetting polysiloxane polymer and methylphenyl polysiloxane resin, with a weight ratio of main component to auxiliary component of 90:10) and mix evenly to obtain the desired silicone resin coating solution. Weigh 2000g of the above-mentioned primary phosphating coating powder, add 2% by mass of the above-mentioned silicone resin coating solution, mix evenly in the above-mentioned rotating container, and then heat to 150°C for drying. After complete drying, a silicone resin coating layer is formed on the inorganic fine powder layer to obtain secondary coating powder.

[0067] (4) Lubricant mixing: After passing the secondary coated powder through a 40-300 mesh sieve, add 0.5% of zinc stearate lubricant by weight of the secondary coated powder and mix evenly to obtain the raw material powder for pressing and molding.

[0068] (5) Pressing and molding: The above raw material powder is pressed into a circular magnetic ring with a pressing pressure load of 2000MPa.

[0069] (6) Annealing heat treatment: The pressed magnetic ring blank was annealed in nitrogen atmosphere at a holding temperature of 750℃ for 1 hour to obtain a soft magnetic metal material. The electron microscope image of the soft magnetic metal material is shown in Figure 2-4.

[0070] Example 2

[0071] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that the thickness of the phosphating layer is approximately 80 nm.

[0072] The preparation method differs from that in Example 1 in that: in step (2), the total content of functional solutes accounts for 2.0% of the total amount of phosphating solution (containing 0.2% aluminum dihydrogen phosphate, 0.6% strontium oxide, 0.2% boric acid, 0.3% magnesium oxide, 0.2% zinc oxide, 0.2% yttrium oxide, 0.2% sodium molybdate, and 0.1% sodium nitrite), while the amount of phosphating solution added is 2.0% of the weight of the mixed powder.

[0073] Example 3

[0074] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that the thickness of the phosphating layer is approximately 50 nm.

[0075] The preparation method differs from that in Example 1 in that: in step (2), the total content of functional solutes accounts for 0.5% of the total amount of phosphating solution (containing 0.05% aluminum dihydrogen phosphate, 0.1% strontium oxide, 0.05% boric acid, 0.05% magnesium oxide, 0.05% zinc oxide, 0.05% yttrium oxide, 0.1% sodium molybdate, and 0.05% sodium nitrite), while the amount of phosphating solution added is 1.0% of the weight of the mixed powder.

[0076] Example 4

[0077] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that the thickness of the phosphating layer is approximately 70 nm.

[0078] The preparation method differs from that in Example 1 in that: in step (2), the total content of functional solutes accounts for 3.0% of the total amount of phosphating solution (containing 0.5% aluminum dihydrogen phosphate, 1.0% strontium oxide, 0.2% boric acid, 0.3% magnesium oxide, 0.3% zinc oxide, 0.3% yttrium oxide, 0.3% sodium molybdate, and 0.1% sodium nitrite), while the amount of phosphating solution added is 0.6% of the weight of the mixed powder.

[0079] Example 5

[0080] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that the thickness of the phosphating layer is approximately 180 nm.

[0081] The preparation method differs from that in Example 1 in that: in step (2), the total content of functional solutes accounts for 20.0% of the total amount of phosphating solution (containing 5.0% aluminum dihydrogen phosphate, 5.0% strontium oxide, 1.0% boric acid, 3.0% magnesium oxide, 3.0% zinc oxide, 1.0% yttrium oxide, 1.5% sodium molybdate, and 0.5% sodium nitrite), while the amount of phosphating solution added is 5.0% of the weight of the mixed powder.

[0082] Example 6

[0083] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that the thickness of the phosphating layer is approximately 180 nm.

[0084] The preparation method differs from that in Example 1 in that: in step (2), the total content of functional solutes accounts for 10.5% of the total amount of phosphating solution (containing 5.0% aluminum dihydrogen phosphate, 1.0% strontium oxide, 0.5% boric acid, 1.0% magnesium oxide, 1.0% zinc oxide, 0.5% yttrium oxide, 1.0% sodium molybdate, and 0.5% sodium nitrite), while the amount of phosphating solution added is 2.0% of the weight of the mixed powder.

[0085] Example 7

[0086] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that the thickness of the phosphating layer is approximately 90 nm.

[0087] The preparation method differs from that in Example 1 in that: in step (2), the total content of functional solutes accounts for 7.0% of the total amount of phosphating solution (containing 2.0% aluminum dihydrogen phosphate, 1.5% strontium oxide, 0.5% boric acid, 1.0% magnesium oxide, 1.0% zinc oxide, 0.3% yttrium oxide, 0.5% sodium molybdate, and 0.2% sodium nitrite), while the amount of phosphating solution added is 0.8% of the weight of the mixed powder.

[0088] Example 8

[0089] This embodiment provides a soft magnetic metal material, the preparation method of which differs from that of Embodiment 1 in that: in step (1), the inorganic fine powder is iron(III) oxide micro-fine powder.

[0090] Example 9

[0091] This embodiment provides a soft magnetic metal material, the preparation method of which differs from that of Embodiment 1 in that: in step (1), the inorganic fine powder is a low melting point glass powder (melting point is 450℃, glass powder composition is SnO-ZnO-P2O5).

[0092] Example 10

[0093] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that: the thickness of the insulating layer is approximately 1.7 μm; and the thickness of the inorganic fine powder layer is 1.2 μm.

[0094] The preparation method differs from that in Example 1 in that: in step (1), the amount of inorganic fine powder added is 0.3% of the weight of the mixed powder.

[0095] Example 11

[0096] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that: the thickness of the insulating layer is approximately 1.9 μm; and the thickness of the inorganic fine powder layer is 1.4 μm.

[0097] The preparation method differs from that in Example 1 in that: in step (1), the amount of inorganic fine powder added is 2.0% of the weight of the mixed powder.

[0098] Example 12

[0099] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that: the thickness of the insulating layer is approximately 1.6 μm; and the thickness of the inorganic fine powder layer is 1.1 μm.

[0100] The preparation method differs from that in Example 1 in that: in step (1), the amount of inorganic fine powder added is 0.8% of the weight of the mixed powder.

[0101] Example 13

[0102] This embodiment provides a soft magnetic metal material, which differs from Embodiment 1 in that: the thickness of the insulating layer is approximately 1.7 μm; and the thickness of the inorganic fine powder layer is 1.2 μm.

[0103] The preparation method differs from that in Example 1 in that: in step (1), the amount of inorganic fine powder added is 1.5% of the weight of the mixed powder.

[0104] Comparative Example 1

[0105] This comparative example provides a soft magnetic metal material, which differs from Example 1 in that: the thickness of the insulating layer is 2.0 μm; and the thickness of the phosphating layer is 150 nm.

[0106] The difference between its preparation method and that of Example 1 is that the phosphating solution uses reagent-grade pure phosphoric acid (85% aqueous phosphoric acid solution) that does not contain various oxides of multiple components.

[0107] Comparative Example 2

[0108] This comparative example provides a soft magnetic metal material, which differs from Example 1 in that the insulating layer consists only of a phosphating layer and a silicone resin layer.

[0109] The preparation method differs from that in Example 1 in that no inorganic fine powder is added.

[0110] The soft magnetic metal materials of the examples and comparative examples were subjected to the following performance tests:

[0111] The permeability, insulation performance, and power dissipation performance of soft magnetic metal materials were tested by fabricating magnetic rings using the same parameters and conditions as described in the above embodiments; specifically, magnetic rings with an outer diameter of 35 mm, an inner diameter of 20 mm, and a thickness of 15 mm were used for testing. The permeability and power dissipation characteristics of the magnetic rings were measured using a BH tester SY-8218 from Iwatsu Chemical Co., Ltd., Japan, under test conditions of 25°C and 50 kHz / 100 mT.

[0112] The strength of soft magnetic metallic materials is characterized by the radial crushing strength of the magnetic ring. The radial crushing strength is given by K = P(DT) / LT. 2 P: crushing load; T: specimen thickness: (outer diameter - inner diameter) / 2; D: specimen outer diameter; L: specimen length.

[0113] The environmental durability test under high temperature and high humidity conditions was conducted using an Aspire GHS-64V temperature and humidity test chamber. The inductance rate was measured over time under the conditions of 85℃ temperature and 85%RH humidity.

[0114] The soft magnetic metal material magnetic rings of Examples 1-13 and Comparative Examples 1-2 were subjected to the above-mentioned performance tests, and the test data are summarized in Table 1 below.

[0115] Table 1

[0116] As can be seen from the experimental data in Table 1, the three insulating layers in the soft magnetic metal material of this invention work together to give the soft magnetic metal material high permeability (≥60μ), high heat resistance, high stability, high strength (radial crushing strength ≥105MPa), and low loss (power consumption <100mW / cm at 25℃, 50kHz / 100mT). 3 It possesses properties such as uniformity, density, and reliability. Furthermore, it exhibits excellent high-temperature environmental stability (the inductance change rate is less than 1% after 1000 hours under high-temperature and high-humidity conditions). Even after prolonged use, it can prevent the deterioration and failure of the magnetic permeability and inductance characteristics of the magnetic core, thus meeting the stringent usage conditions in fields such as new energy vehicles and photovoltaics.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Industrial applicability

[0118] This invention provides a soft magnetic metal material, its preparation method, and its applications. The soft magnetic metal material comprises soft magnetic metal powder and an insulating layer coating the surface of the powder. Along the radial direction of the soft magnetic metal material, from the inside out, the insulating layer sequentially comprises a phosphating layer, an inorganic fine powder layer, and a silicone resin layer. Through the synergistic effect of the phosphating layer, the inorganic fine powder layer, and the silicone resin layer, the soft magnetic metal material of this invention possesses properties such as high heat resistance, high stability, high strength, and low loss. It is not only uniform, dense, and reliable, but also exhibits excellent high-temperature environmental stability under harsh conditions such as high temperature and high humidity. Even after prolonged use, it can prevent the degradation and failure of the magnetic permeability and inductance characteristics of the core, demonstrating good economic value and application prospects.

Claims

1. A soft magnetic metallic material, characterized in that, It includes soft magnetic metal powder and an insulating layer covering the surface of the soft magnetic metal powder; along the radial direction of the soft magnetic metal material from the inside to the outside, the insulating layer sequentially includes a phosphate layer, an inorganic fine powder layer and a silicone resin layer.

2. The soft magnetic metal material according to claim 1, characterized in that, The phosphating layer is formed by a phosphating reaction between the phosphating solution and the surface of the soft magnetic metal powder; the phosphating solution contains a phosphoric acid solution and a functional solute, the functional solute including one or more of aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, and sodium nitrite.

3. The soft magnetic metal material according to claim 2, characterized in that, In the phosphating solution, the mass percentage of the functional solute is 0.5% to 20.0%.

4. The soft magnetic metal material according to claim 1, characterized in that, The inorganic fine powder layer includes one or more of MnZn ferrite, iron(II) oxide, glass powder, and silicate powder.

5. The soft magnetic metal material according to claim 1, characterized in that, The thickness of the insulating layer is 0.02–2 μm; Preferably, the thickness of the phosphating layer is 50–200 nm; the thickness of the inorganic fine powder layer is 0.02–1.5 μm; and the thickness of the silicone resin layer is 0.02–1.5 μm.

6. The soft magnetic metal material according to claim 1, characterized in that, The soft magnetic metal powder includes one or more of the following: Fe powder, Fe-Si powder, Fe-Si-Al powder, Fe-Si-Cr powder, Fe-Ni powder, Fe-Si-BC amorphous powder, Fe-Si-BCP amorphous powder, Fe-Cr-Si-BC amorphous powder, or Fe-Nb-Cu-Si-B nanocrystalline powder. The average particle size D50 of the soft magnetic metal powder is 2–100 μm.

7. The soft magnetic metal material according to claim 1, characterized in that, The silicone resin layer is formed of silicone resin, which includes a main component and auxiliary components. The main component includes heat-resistant silicone resin or silicone resin, and the auxiliary components include one or more of epoxy resin, phenolic resin and polyvinyl butyral.

8. The method for preparing the soft magnetic metallic material according to any one of claims 1-7, characterized in that, Includes the following steps: After uniformly mixing the soft magnetic metal raw powder and the inorganic fine powder, a mixed powder is obtained. The mixed powder is first sprayed with a phosphating solution. The phosphating solution reacts with the surface of the soft magnetic metal raw powder but does not react with the inorganic fine powder, so as to form a phosphating coating layer and an inorganic fine powder coating layer on the surface of the soft magnetic metal raw powder in sequence. Then, silicone resin is used for coating to form a silicone resin coating layer on the inorganic fine powder coating layer; Then, after granulation, drying, and sieving, lubricant is added and the mixture is pressed into shape. Finally, annealing heat treatment is performed to obtain soft magnetic metal material.

9. The preparation method according to claim 8, characterized in that, The amount of the inorganic fine powder is 0.3% to 2.0% of the mass of the mixed powder; And / or, the phosphating solution is used in an amount of 0.05% to 5.0% of the mass of the mixed powder; And / or, the phosphating temperature is 25°C to 100°C; And / or, the pressing pressure is 500MPa to 2300MPa; the pressing method is room temperature pressing; And / or, the annealing heat treatment temperature is 600℃~800℃; the annealing heat treatment is carried out under the protection of an inert gas atmosphere.

10. The application of the soft magnetic metal material according to any one of claims 1-7 or the soft magnetic metal material prepared by the preparation method according to claim 8 or 9 in inductor components.

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