Soft magnetic metal material and preparation method and application thereof

Abstract

The invention relates to the technical field of magnetic functional materials, in particular to a soft magnetic metal material and a preparation method and application thereof. The soft magnetic metal material comprises soft magnetic metal raw powder and an insulating layer wrapping the surface of the soft magnetic metal raw powder. The insulating layer sequentially comprises a phosphate coating, an inorganic fine powder layer and a silicon resin layer from inside to outside in the radial direction of the soft magnetic metal material. Through mutual cooperation of the phosphate coating, the inorganic fine powder layer and the silicon resin layer, the soft magnetic metal material has the performance of high heat resistance, high stability, high strength, low loss and the like, is uniform, compact and reliable, has good high-temperature environment stability under the severe environment conditions of high temperature, high humidity and the like, and can still be used for a long time even if the soft magnetic metal material is used for a long time. And deterioration and failure of the magnetic conductivity characteristic and the inductance characteristic of the magnetic core can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic functional materials, and particularly relates to a soft magnetic metal material, a preparation method thereof, and an application thereof. Background Art

[0002] Magnetic powder cores usually form an insulating coating layer on the powder surface to reduce eddy current loss. Organic insulating layers (such as epoxy resin) have good adhesion and flexibility, but their high-temperature stability is poor and they will gradually decompose as the annealing temperature or heating time increases. Inorganic insulating layers (such as SiO 2 ) have high resistivity and good thermal stability, but it is difficult to uniformly coat SiO 2 particles etc. on the surface of soft magnetic metals only by physical coating such as stirring. In the phosphating method widely used in the field of magnetic powder cores, since the binary phosphates such as iron phosphate formed by simply using phosphoric acid corrosion have poor porosity and thermal stability, it is difficult to form a dense insulating layer with high resistivity. In addition, in order to prevent the insulating coating layer from decomposing and deteriorating during annealing, the annealing temperature often has to be set relatively low, and thus the soft magnetic materials obtained usually have low strength and cannot meet the severe conditions of actual use in new energy vehicles, photovoltaic applications, etc. Summary of the Invention

[0003] The present invention provides a soft magnetic metal material, a preparation method thereof, and an application thereof, so as to solve the problems existing in the existing soft magnetic metal materials, such as poor thermal stability, difficulty in forming a dense insulating layer with high resistivity, and low strength.

[0004] According to the first aspect of the present invention, the present invention provides a soft magnetic metal material, which includes a soft magnetic metal raw powder and an insulating layer coated on the surface of the soft magnetic metal raw powder; along the radial direction of the soft magnetic metal material from the inside to the outside, the insulating layer sequentially includes a phosphating layer, an inorganic fine powder layer, and a silicone resin layer.

[0005] Further, the phosphating layer is formed by a phosphating reaction between a phosphating solution and the surface of the soft magnetic metal raw powder; the phosphating solution includes a phosphoric acid solution and a functional solute, and the functional solute includes one or more of aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, and sodium nitrite.

[0006] Further, in the phosphating solution, the mass percentage of the functional solute is 0.5 - 20.0%.

[0007] Further, the inorganic fine powder layer includes one or more of MnZn ferrite, magnetite, glass powder, and silicate powder.

[0008] Further, 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; the thickness of the silicone resin layer is 0.02-1.5 μm.

[0009] Further, the soft magnetic metal raw powder includes one or more of Fe powder, Fe-Si powder, Fe-Si-Al powder, Fe-Si-Cr powder, Fe-Ni powder, Fe-Si-B-C amorphous powder, Fe-Si-B-C-P amorphous powder, Fe-Cr-Si-B-C amorphous powder, or Fe-Nb-Cu-Si-B nanocrystalline powder.

[0010] Further, the average particle size D50 of the soft magnetic metal raw powder is 2-100 μm.

[0011] Further, the silicone resin layer is formed of a silicone resin, the silicone resin includes a main component and an auxiliary component, the main component includes a heat-resistant silicone resin or a silicone resin, and the auxiliary component includes one or more of an epoxy resin, a phenolic resin, and polyvinyl butyral.

[0012] According to the second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned soft magnetic metal material, including 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 spray-phosphated with a phosphating solution, and 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 sequentially form a phosphating coating layer and an inorganic fine powder coating layer on the surface of the soft magnetic metal raw powder; Then, it is coated with a silicone resin to form a silicone resin coating layer on the inorganic fine powder coating layer; Then, after granulation, drying, and screening, a lubricant is added and pressed into shape; Finally, annealing heat treatment is carried out to obtain the soft magnetic metal material.

[0013] Further, the dosage of the inorganic fine powder is 0.3% - 2.0% of the mass of the mixed powder; Further, the dosage of the phosphating solution is 0.05% - 5.0% of the mass of the mixed powder; Further, the temperature of the phosphating is 25°C - 100°C; Further, the pressure of the pressing into shape is 500 MPa - 2300 MPa; the method of pressing into shape is room temperature pressing; Further, the temperature of the annealing heat treatment is 600°C - 800°C; the annealing heat treatment is carried out under the protection of an inert gas atmosphere. The inert gas includes nitrogen or argon, etc.

[0014] According to the third aspect of the present invention, the present invention also provides an application of the above-mentioned soft magnetic metal material or the soft magnetic metal material prepared by the above-mentioned preparation method in an inductive element. Among them, the inductive element includes a power inductor, a filter inductor, and the like.

[0015] A soft magnetic metal material provided by the present invention includes metal raw powder and an insulating layer coated on the surface of the metal raw powder. The insulating layer includes a phosphating layer, an inorganic fine powder layer, and a silicone resin layer. The three-layer insulating coating structure of the soft magnetic metal material of the present invention cooperates with each other, so that the soft magnetic metal material has properties such as 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 deterioration and failure of the magnetic permeability characteristics and inductance characteristics of the magnetic core. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic structural diagram of a soft magnetic metal material provided in Experimental Example 1 of the present invention.

[0018] Figure 2 It is one of the scanning electron microscope images of a soft magnetic metal material provided in Embodiment 1 of the present invention.

[0019] Figure 3 It is another scanning electron microscope image of a soft magnetic metal material provided in Embodiment 1 of the present invention.

[0020] Figure 4 It is still another scanning electron microscope image of a soft magnetic metal material provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0022] According to the first aspect of the present invention, the present invention provides a soft magnetic metal material, comprising soft magnetic metal raw powder and an insulating layer coated on the surface of the soft magnetic metal raw powder; along the radial direction of the soft magnetic metal material from inside to outside, the insulating layer sequentially comprises a phosphating layer, an inorganic fine powder layer and a silicone resin layer.

[0023] The soft magnetic metal material of the present invention comprises soft magnetic metal raw powder and an insulating layer coated on the surface of the soft magnetic metal raw powder, and the insulating layer can reduce eddy current loss. 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 raw powder with a multi-component phosphating solution, has strong bonding with the soft magnetic metal raw powder, good compactness and high resistivity. Coating the inorganic fine powder layer on the phosphating layer can not only improve the magnetic permeability characteristics of the soft magnetic metal material and reduce the loss, but also greatly increase the strength of the soft magnetic metal material after heat treatment, and improve the reliability of the soft magnetic metal material against vibration and high temperature. As the outermost layer of the insulating layer, the silicone resin layer is also an insulating material itself, which can further increase the resistivity of the material, improve the insulation performance of the soft magnetic metal material, and reduce eddy current loss. The silicone resin layer also has the characteristic of high temperature resistance, can improve the thermal stability of the soft magnetic metal material, so that it can maintain good magnetic properties in a high temperature environment. The silicone resin layer can improve the mechanical strength of the soft magnetic metal material, make it more durable in the process of processing and use, and the silicone resin layer can also provide additional protection, enhance the corrosion resistance of the soft magnetic metal material, so that it can maintain its performance in a harsh environment. The three-layer insulating coating structure of the soft magnetic metal material of the present invention, with the three layers cooperating with each other, enables the soft magnetic metal material to have properties such as 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 deterioration and failure of the magnetic permeability characteristics and inductance characteristics of the magnetic core.

[0024] Further, the phosphating layer is formed by a phosphating reaction of the phosphating solution with the surface of the soft magnetic metal raw powder; the phosphating solution comprises a phosphoric acid solution and a functional solute, and the functional solute comprises one or more of aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, sodium nitrite. By selecting a suitable type of functional solute to form a specific phosphating solution, a good synergistic effect can be formed with the surface of the metal raw powder, and a phosphating coating layer with strong bonding and thin thickness can be in-situ formed on the surface of the metal raw powder. The phosphating coating layer has high resistivity and can effectively reduce eddy current loss.

[0025] It should be noted that the main component of the phosphating solution is phosphoric acid solution, and functional components including one or more of aluminum dihydrogen phosphate, strontium oxide, boric acid, magnesium oxide, zinc oxide, yttrium oxide, sodium molybdate, and sodium nitrite are added. Aluminum dihydrogen phosphate can provide phosphate ions and aluminum ions simultaneously. As a catalyst, it promotes the phosphating reaction, improves the phosphating efficiency, enhances the corrosion resistance of the phosphating film, enables it to have better protection in various environments, and can also improve the physical properties of the phosphating film, such as hardness, wear resistance, and adhesion, making it more suitable for actual application requirements. Strontium oxide and yttrium oxide can improve the thermal stability of the material, boric acid helps oxides dissolve in phosphoric acid, magnesium oxide can increase the resistivity of the phosphating layer material, zinc oxide can improve the corrosion resistance of the material, and sodium molybdate and sodium nitrite help form a dense phosphating layer.

[0026] Further, in the phosphating solution, the mass percentage of the functional solute is 0.5 - 20.0%.

[0027] 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. By limiting the mass percentage of the functional solute in the phosphating solution within a reasonable range value, it is more conducive to increasing the resistivity of the phosphating layer, improving the insulation performance, and more effectively reducing eddy current loss.

[0028] According to some specific embodiments of the present invention, in the phosphating solution, it contains 0.1 - 5.0% of aluminum dihydrogen phosphate, 0.1 - 5.0% of strontium oxide, 0.05 - 1.0% of boric acid, 0.05 - 1.0% of magnesium oxide, 0.05 - 1.0% of zinc oxide, 0.1 - 5.0% of yttrium oxide, 0.05 - 1.0% of sodium molybdate, and 0.05 - 1.0% of sodium nitrite, and the rest is phosphoric acid solution. In some specific embodiments, the mass concentration of the phosphoric acid solution is 80 - 90%.

[0029] Further, the inorganic fine powder layer includes one or more of MnZn ferrite, magnetite, glass powder, and silicate powder.

[0030] The purpose of coating an inorganic fine powder layer on the phosphating layer in the present invention is to further increase the resistivity and improve the strength (green compact strength) of the soft magnetic metal material after heat treatment. Generally, the insulating coating material of the soft magnetic metal material is required to be a non-magnetic substance. Excessive addition will lead to a decrease in magnetic permeability and dilution of various magnetic properties. Therefore, the addition amount must be controlled within the necessary limit. The above-mentioned inorganic fine powder selected in the present invention is some oxides with magnetic properties, which have both insulation and soft magnetic properties (less decrease in magnetic permeability). When these inorganic fine powder particles are annealed at 600°C to 800°C, due to their reactivity with the surface of the metal soft magnetic powder or the presence of a liquid phase, the green compact strength of the soft magnetic material can be greatly improved. In this way, both the resistivity and strength of the soft magnetic metal material can be further increased, and the magnetic permeability of the soft magnetic metal material will not be affected.

[0031] Furthermore, the thickness of the insulating layer is 0.02 - 2 μm. By limiting the thickness of the insulating layer within a reasonable range value, it is more conducive to improving the insulation ability and reducing the eddy current loss.

[0032] 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; 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 within reasonable range values, better synergy can be achieved among the layers, which is more conducive to improving the overall performance of the soft magnetic metal material.

[0033] Furthermore, the soft magnetic metal raw powder includes one or more of Fe powder, Fe-Si powder, Fe-Si-Al powder, Fe-Si-Cr powder, Fe-Ni powder, Fe-Si-B-C amorphous powder, Fe-Si-B-C-P amorphous powder, Fe-Cr-Si-B-C amorphous powder or Fe-Nb-Cu-Si-B nanocrystalline powder. By selecting a suitable type of soft magnetic metal raw powder to cooperate with the insulating layer with a specific structure, better synergy can be formed between the soft magnetic metal raw powder and the insulating layer, which is more conducive to improving the overall performance of the soft magnetic metal material.

[0034] Furthermore, the average particle size D50 of the soft magnetic metal raw powder is 2 - 100 μm.

[0035] Further, the silicone resin layer is formed of a silicone resin, which includes a main component and an auxiliary component. The main component includes a heat-resistant silicone resin or a silicone resin, and the auxiliary component includes one or more of an epoxy resin, a phenolic resin, and polyvinyl butyral. By defining the composition of the silicone resin layer, the overall performance of the soft magnetic metal material can be more effectively improved. 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.

[0036] 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, which 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 spray-phosphated with a phosphating solution, and 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 sequentially form a phosphating coating layer and an inorganic fine powder coating layer on the surface of the soft magnetic metal raw powder; Then, it is coated with a silicone resin to form a silicone resin coating layer on the inorganic fine powder coating layer; Then, after granulation, drying, and screening, a lubricant is added and pressed into shape; Finally, annealing heat treatment is carried out to obtain the soft magnetic metal material.

[0037] In the method for preparing the soft magnetic metal material of the present invention, first, the metal raw powder and the inorganic fine powder are uniformly mixed to obtain a mixed powder, and then the mixed powder is spray-phosphated with a phosphating solution. This is beneficial for the inorganic fine powder to be evenly distributed among the particles of the soft magnetic metal raw powder, and a continuous process without interruption is formed during the coating processes such as phosphating-silicone resin coating, without an intermediate mixing process. After forming a phosphating coating layer and an inorganic fine powder coating layer on the surface of the metal raw powder, it is then coated with a heat-resistant silicone resin to form a silicone resin coating layer. Finally, through pressing into shape and annealing heat treatment, a multi-component phosphating coating layer is formed through a series of vitrification reactions to form a multi-component phosphate glass-based phosphating layer, the inorganic fine powder coating layer 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. The method for preparing the soft magnetic metal material of the present invention is simple and easy to implement, has a low cost, and is suitable for large-scale industrial batch production.

[0038] Further, the dosage of the inorganic fine powder is 0.3% - 2.0% of the mass of the mixed powder. By limiting the dosage of the inorganic fine powder within a reasonable range value, it is beneficial to form an inorganic fine powder layer with an ideal thickness, and at the same time, it does not affect the reaction between the phosphating solution and the surface of the metal raw powder.

[0039] Optionally, the dosage 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% etc. of the mass of the mixed powder.

[0040] Furthermore, the dosage of the phosphating solution is 0.6% - 5.0% of the mass of the mixed powder. By limiting the dosage of the phosphating solution within a reasonable range value, it is beneficial to the reaction on the surface of the metal raw powder by the phosphating solution, improving the phosphating efficiency, and then forming a dense and stable phosphating layer.

[0041] Optionally, the dosage of the phosphating solution 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% etc. of the mass of the mixed powder.

[0042] Furthermore, the temperature of the phosphating is 25°C - 100°C. By selecting the phosphating temperature within a reasonable range value, it is beneficial to improve the efficiency of the phosphating treatment, thereby forming a dense and stable phosphating layer.

[0043] Furthermore, the pressure of the pressing forming is 500 MPa - 2300 MPa; the way of the pressing forming is normal temperature pressing. By limiting the pressure and way of the pressing forming, it is beneficial to form a high-quality insulating layer.

[0044] Furthermore, the temperature of the annealing heat treatment is 600°C - 800°C; the annealing heat treatment is carried out under the protection condition of an inert gas atmosphere. By limiting the temperature of the annealing heat treatment and the inert gas condition, it is beneficial to the high-quality formation of each layer in the insulating layer. In some specific embodiments, the inert gas refers to nitrogen.

[0045] According to the third aspect of the present invention, the present invention also provides the application of the above soft magnetic metal material or the soft magnetic metal material prepared by the above preparation method in a magnetic powder core inductor product.

[0046] Example 1 This example provides a soft magnetic metal material, as Figure 1 shown, including a soft magnetic metal raw powder and an insulating layer coated on the surface of the soft magnetic metal raw powder; along the radial direction of the soft magnetic metal material from inside to outside, the insulating layer successively includes a phosphating layer, an inorganic fine powder layer and a silicone resin layer. Among them, the thickness of the insulating layer is about 2 μm; the thickness of the phosphating layer is about 120 nm; the thickness of the inorganic fine powder layer is about 1.5 μm; the thickness of the silicone resin layer is about 0.5 μm.

[0047] Its preparation method includes the following steps: (1)The soft magnetic metal material uses Fe-9.6Si-5.4Al raw powder: 2000 g of iron-silicon-aluminum raw powder with D50 = 25 μm and 20 g of MnZn ferrite powder with D50 = 5 μm are evenly mixed for 30 min to obtain a mixed powder.

[0048] (2)Phosphating coating: First, prepare a functional solute including oxides, etc. A phosphating solution with a content of 5.0% by mass percentage (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 remaining is 85% phosphoric acid aqueous solution of reagent grade); weigh the functional solute powder according to the specified ratio, dissolve it in the phosphoric acid solution heated to 150 °C in sequence, and through uniform stirring, make various functional solute oxides, etc. uniformly dissolve in the heated phosphoric acid solution, cool it to room temperature, and then a transparent and precipitate-free phosphating solution of the present invention can be obtained. Then, add 2000 g of the above mixed powder into a container with blades that can rotate and stir (rotation speed is 150 rpm / min), and while rotating and stirring, spray and uniformly add the above phosphating solution accounting for 1.0% of the weight of the mixed powder. After all are added, stir for 10 min and carry out phosphating at room temperature (25 °C). Then, heat it to 150 °C while stirring for drying. After the powder is completely dried, a phosphating coating layer and an inorganic fine powder coating layer can be sequentially formed on the surface of the metal raw powder to obtain a primary phosphating-coated powder.

[0049] (3)Silicone resin coating: Prepare a silicone resin coating solution: Dissolve 50% of heat-resistant silicone resin powder (including thermosetting polysiloxane polymer and methylphenyl polysiloxane resin, the weight ratio of the main component to the auxiliary component is 90:10) in ethyl acetate solution, and mix evenly to obtain the specified silicone resin coating solution. Weigh 2000 g of the above primary phosphating-coated powder, add 2% by mass percentage of the above silicone resin coating solution, mix evenly in the above rotating container, then heat up to 150 °C for drying, and after complete drying, form a silicone resin coating layer on the inorganic fine powder layer to obtain a secondary-coated powder.

[0050] (4)Lubricant mixing: After passing the secondary-coated powder through a 40 - 300 mesh sieve, add 0.5% of zinc stearate lubricant by the mass of the secondary-coated powder and mix evenly to obtain the raw powder for pressing and forming.

[0051] (5)Pressing and forming: Press the above raw powder into a circular magnetic ring, and the pressing pressure load is 2000 MPa.

[0052] (6) Annealing treatment: The pressed magnetic ring green compact is subjected to annealing treatment in nitrogen. The holding temperature is 750 °C and the holding time is 1 h to obtain a soft magnetic metal material. The electron micrograph of the soft magnetic metal material is as shown in Figures 2 - 4 shown.

[0053] Example 2 This example provides a soft magnetic metal material, which is different from that of Example 1 in that the thickness of the phosphating layer is about 80 nm.

[0054] The difference in its preparation method from that of Example 1 is that in step (2), the total content of functional solutes accounts for 2.0% of the total amount of the 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, 0.1% sodium nitrite), and the addition amount of the phosphating solution is 2.0% of the weight of the mixed powder.

[0055] Example 3 This example provides a soft magnetic metal material, which is different from that of Example 1 in that the thickness of the phosphating layer is about 50 nm.

[0056] The difference in its preparation method from that of Example 1 is that in step (2), the total content of functional solutes accounts for 0.5% of the total amount of the 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, 0.05% sodium nitrite), and the addition amount of the phosphating solution is 1.0% of the weight of the mixed powder.

[0057] Example 4 This example provides a soft magnetic metal material, which is different from that of Example 1 in that the thickness of the phosphating layer is about 70 nm.

[0058] The difference in its preparation method from that of Example 1 is that in step (2), the total content of functional solutes accounts for 3.0% of the total amount of the 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, 0.1% sodium nitrite), and the addition amount of the phosphating solution is 0.6% of the weight of the mixed powder.

[0059] Example 5 This example provides a soft magnetic metal material, which is different from that of Example 1 in that the thickness of the phosphating layer is about 180 nm.

[0060] The difference in its preparation method from that of Example 1 lies in that: in step (2), the total content of functional solutes accounts for 20.0% of the total amount of the phosphating solution (containing 5.0% of aluminum dihydrogen phosphate, 5.0% of strontium oxide, 1.0% of boric acid, 3.0% of magnesium oxide, 3.0% of zinc oxide, 1.0% of yttrium oxide, 1.5% of sodium molybdate, and 0.5% of sodium nitrite), and the addition amount of the phosphating solution is 5.0% of the weight of the mixed powder.

[0061] Example 6 This example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the phosphating layer is about 180 nm.

[0062] The difference in its preparation method from that of Example 1 lies in that: in step (2), the total content of functional solutes accounts for 10.5% of the total amount of the phosphating solution (containing 5.0% of aluminum dihydrogen phosphate, 1.0% of strontium oxide, 0.5% of boric acid, 1.0% of magnesium oxide, 1.0% of zinc oxide, 0.5% of yttrium oxide, 1.0% of sodium molybdate, and 0.5% of sodium nitrite), and the addition amount of the phosphating solution is 2.0% of the weight of the mixed powder.

[0063] Example 7 This example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the phosphating layer is about 90 nm.

[0064] The difference in its preparation method from that of Example 1 lies in that: in step (2), the total content of functional solutes accounts for 7.0% of the total amount of the phosphating solution (containing 2.0% of aluminum dihydrogen phosphate, 1.5% of strontium oxide, 0.5% of boric acid, 1.0% of magnesium oxide, 1.0% of zinc oxide, 0.3% of yttrium oxide, 0.5% of sodium molybdate, and 0.2% of sodium nitrite), and the addition amount of the phosphating solution is 0.8% of the weight of the mixed powder.

[0065] Example 8 This example provides a soft magnetic metal material, and the difference in its preparation method from that of Example 1 lies in that: in step (1), the inorganic fine powder is fine powder of ferroferric oxide.

[0066] Example 9 This example provides a soft magnetic metal material, and the difference in its preparation method from that of Example 1 lies in that: in step (1), the inorganic fine powder is fine powder of low melting point glass powder (the melting point is 450 °C, and the glass powder composition is SnO-ZnO-P 2 O 5 )

[0067] Example 10 This example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the insulating layer is about 1.7 μm; the thickness of the inorganic fine powder layer is 1.2 μm.

[0068] The difference in its preparation method from that of Example 1 lies in that: in step (1), the addition amount of the inorganic fine powder is 0.3% of the weight of the mixed powder.

[0069] Example 11 This example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the insulating layer is about 1.9 μm; the thickness of the inorganic fine powder layer is 1.4 μm.

[0070] The difference in its preparation method from that of Example 1 lies in that: in step (1), the addition amount of the inorganic fine powder is 2.0% of the weight of the mixed powder.

[0071] Example 12 This example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the insulating layer is about 1.6 μm; the thickness of the inorganic fine powder layer is 1.1 μm.

[0072] The difference in its preparation method from that of Example 1 lies in that: in step (1), the addition amount of the inorganic fine powder is 0.8% of the weight of the mixed powder.

[0073] Example 13 This example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the insulating layer is about 1.7 μm; the thickness of the inorganic fine powder layer is 1.2 μm.

[0074] The difference in its preparation method from that of Example 1 lies in that: in step (1), the addition amount of the inorganic fine powder is 1.5% of the weight of the mixed powder.

[0075] Comparative Example 1 This comparative example provides a soft magnetic metal material, which is different from that of Example 1 in that: the thickness of the insulating layer is 2.0 μm; the thickness of the phosphating layer is 150 nm.

[0076] The difference in its preparation method from that of Example 1 lies in that: the phosphating solution uses reagent-grade pure phosphoric acid (85% phosphoric acid aqueous solution) without various oxides of multiple components.

[0077] Comparative Example 2 This comparative example provides a soft magnetic metal material, which is different from that of Example 1 in that: the insulating layer is only composed of a phosphating layer and a silicone resin layer.

[0078] The difference in its preparation method from that of Example 1 lies in that: no inorganic fine powder is added.

[0079] The soft magnetic metal materials of the examples and comparative examples were subjected to the following performance tests: The magnetic permeability, insulation performance and power consumption performance of the soft magnetic metal material are all tested by preparing the soft magnetic metal material into a magnetic ring under the conditions of the above embodiment using the same parameter conditions; that is, using a magnetic ring of [outer diameter 35mm×inner diameter 20mm×thickness 15mm] for testing. Among them, the magnetic permeability and power consumption characteristics of the magnetic ring are measured using the BH tester SY-8218 of Japan Iwatsu Co., Ltd. under the test conditions of 25°C and 50kHz / 100mT.

[0080] The strength of soft magnetic metal materials is characterized by the radial crushing strength of the magnetic ring. Among them, the radial crushing strength K = P (DT) / LT 2 , P: crushing load; T: specimen thickness: (outer diameter - inner diameter) / 2; D: specimen outer diameter; L: specimen length.

[0081] Environmental durability test under high temperature and high humidity conditions, using GHS-64V temperature and humidity test chamber manufactured by ASPARK, under the conditions of temperature 85°C / humidity 85%RH, to test the change rate of inductance over time.

[0082] The soft magnetic metal material magnetic rings of Examples 1 to 13 and Comparative Examples 1 to 2 were subjected to the above-mentioned performance tests, and the test data are summarized in the following Table 1.

[0083] Table 1

[0084] It can be seen from the experimental data in Table 1 that the three-layer insulating coating structure in the soft magnetic metal material of the present invention cooperates with each other, which can make the soft magnetic metal material have high magnetic permeability (≥60μ), high heat resistance, high stability, high strength (radial crushing strength ≥105MPa), low loss (50kHz / 100mT, power consumption <100mW / cm under 25℃ condition), high heat resistance, high stability, high strength (radial crushing strength ≥105MPa), low heat resistance, ... 3 ) and other properties, which are not only uniform, dense and reliable, but also have good high temperature environment stability under harsh environmental conditions such as high temperature and high humidity (the inductance change rate after 1000 hours under high temperature and high humidity conditions is less than 1%). Even if used for a long time, it can prevent the magnetic permeability and inductance characteristics of the magnetic core from deteriorating and failing, and can meet the harsh use conditions in new energy vehicles and photovoltaics.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soft magnetic metal material, characterized in that: It comprises soft magnetic metal powder and an insulating layer coated on the surface of the soft magnetic metal powder; along the radial direction of the soft magnetic metal material from inside to outside, the insulating layer comprises a phosphating layer, an inorganic fine powder layer and a silicone resin layer in sequence.

2. The soft magnetic metal material according to claim 1, characterized in that: The phosphating layer is formed by a phosphating reaction between a phosphating solution and the surface of the soft magnetic metal raw powder; the phosphating solution contains a phosphoric acid solution and a functional solute, and the functional solute includes 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 0.5-20.0%.

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, ferroferric 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 to 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 raw powder includes one or more of 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 raw powder is 2 to 100 μm.

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

8. The method for preparing the soft magnetic metal material according to any one of claims 1 to 7, characterized in that: The steps include: The soft magnetic metal raw powder and the inorganic fine powder are uniformly mixed to obtain a mixed powder; the mixed powder is first sprayed with a phosphating solution, and 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 sequentially form a phosphating coating layer and an inorganic fine powder coating layer on the surface of the soft magnetic metal raw powder; Then coating with silicone resin to form a silicone resin coating layer on the inorganic fine powder coating layer; Then after granulation, drying and screening, lubricant is added and pressed into shape; Finally, annealing heat treatment is performed to obtain a 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 pressure of the pressing is 500MPa to 2300MPa; the pressing is performed at room temperature; And / or, the temperature of the annealing heat treatment is 600° C. to 800° C.; the annealing heat treatment is performed under the protection condition of an inert gas atmosphere.

10. Use of the soft magnetic metal material according to any one of claims 1 to 7 or the soft magnetic metal material prepared by the preparation method according to claim 8 or 9 in an inductor element.

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