Magnetically soft alloy powder with composite coating layer structure, preparation method of magnetically soft alloy powder and magnetically soft alloy inductor

Abstract

The invention provides magnetically soft alloy powder with a composite coating layer structure, a preparation method of the magnetically soft alloy powder and a magnetically soft alloy inductor. The magnetically soft alloy powder comprises an alloy powder base material, an iron-nitrogen layer, an insulating layer and a silicon oxide layer, wherein the surface of the alloy powder base material is coated with the iron-nitrogen layer, the insulating layer and the silicon oxide layer. The preparation method comprises the following steps: (1) nitriding an alloy powder base material to obtain first powder coated with an iron-nitrogen layer; (2) mixing the first powder, absolute ethyl alcohol, an inorganic oxide precursor, deionized water and ammonia water, carrying out coating treatment, carrying out solid-liquid separation, and then carrying out drying treatment to obtain second powder coated with an insulating layer; and (3) the second powder, organic silicon resin and an organic solvent are mixed and stirred under the heating condition till the organic solvent is completely volatilized, and the magnetically soft alloy powder coated with the silicon oxide layer is obtained. The soft magnetic alloy powder provided by the invention has high hardness, high insulation stability and excellent magnetoelectric property, can avoid the phenomena of magnetic powder deformation and insulation layer damage, and also has good soft magnetic property.

Description

Technical Field

[0001] This invention belongs to the field of magnetic materials technology, and relates to a soft magnetic alloy powder, particularly a soft magnetic alloy powder with a composite coating structure, its preparation method, and a soft magnetic alloy inductor. Background Technology

[0002] As high-end equipment such as new energy vehicles, 5G communications, industrial power supplies, and aerospace are upgraded towards higher frequencies, greater integration, and higher power density, third-generation semiconductor materials, represented by gallium nitride (GaN), are being applied on a large scale. Their switching frequencies have broken through the MHz level, and their power density is significantly improved compared to traditional silicon-based devices. Inductors, as core components for energy storage, filtering, and conversion in power electronic equipment, directly determine the efficiency, size, and reliability of the entire system. However, magnetic core materials, as important components of inductors, have become a key bottleneck restricting technological upgrades.

[0003] Currently, inductor core materials are mainly divided into two categories: nickel-zinc ferrite and soft magnetic alloy materials. Nickel-zinc ferrite is widely used in low-to-medium frequency and low-power applications due to its low cost and low hysteresis loss. However, limited by its crystal structure, its saturation magnetization is low, it easily saturates under high current conditions, and its permeability decays rapidly with increasing frequency, failing to meet the requirements of MHz-level high-frequency and high-power-density applications. In contrast, soft magnetic alloy materials can achieve saturation magnetization exceeding 1.0T, have high permeability, and excellent temperature stability, making them suitable for high-frequency, high-current applications and a key candidate material for high-end inductors.

[0004] However, the large-scale production and performance improvement of soft magnetic alloy inductors face multiple technical obstacles. In the manufacturing process, powder surface treatment and mixing are crucial steps determining product performance: surface treatment requires the formation of a high-resistivity insulating layer to block eddy current paths and reduce eddy current losses, but traditional insulating materials (such as silicon oxide, alumina, and titanium oxide) are mostly brittle. In the mixing stage, to ensure slurry uniformity, strong mechanical processes such as sand milling, ball milling, and high-speed stirring are required. The intense collisions between particles not only cause severe plastic deformation of the magnetic powder but also damage and detachment of the brittle insulating layer. These phenomena directly lead to a series of problems, such as: magnetic powder deformation causing a sharp decrease in inductor permeability and a surge in hysteresis losses; and insulation layer damage causing short circuits between the magnet and electrodes, a drop in resistivity, and an exponential increase in eddy current losses.

[0005] Therefore, it is evident that developing a soft magnetic alloy powder that combines high hardness, high insulation stability, and excellent magnetoelectric properties, effectively avoiding magnetic powder deformation and insulation layer damage, while also ensuring good soft magnetic properties, has become an urgent problem for those skilled in the art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a soft magnetic alloy powder with a composite coating structure, its preparation method, and a soft magnetic alloy inductor, which combines high hardness, high insulation stability, and excellent magnetoelectric properties, effectively avoiding magnetic powder deformation and insulation layer damage, while also ensuring good soft magnetic properties.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a soft magnetic alloy powder with a composite coating structure, comprising an alloy powder substrate and an iron-nitrogen layer, an insulating layer, and a silicon oxide layer sequentially coating the surface of the alloy powder substrate from the inside out.

[0009] The alloy powder substrate includes metallic iron and / or iron-based alloys.

[0010] The soft magnetic alloy powder provided by this invention has a composite coating structure of "iron-nitrogen layer + insulating layer + silicon oxide layer". The iron-nitrogen layer, due to its high hardness, significantly improves the wear resistance and impact resistance of the iron-based magnetic powder, exhibiting minimal morphological change and no performance degradation after ball milling. The insulating layer, with its high resistivity, effectively blocks eddy current paths between particles, optimizing the high-frequency characteristics of the material. The outermost silicon oxide layer effectively protects the inner brittle insulating layer, preventing it from detaching and being damaged during ball milling. Therefore, the above three-layer composite coating structure achieves synergistic optimization of wear resistance and magnetoelectric properties, fully meeting the performance requirements of high-frequency operation, integration, and high power density.

[0011] And / or, the alloy powder substrate includes at least one of Fe, FeSi, FeSiAl, FeSiCr, FeNi, FeNiMo, FeCo, or FeCoNi.

[0012] And / or, the nitrogen content in the soft magnetic alloy powder is 0.1-0.5 wt%.

[0013] And / or, the insulating layer is made of inorganic oxide, including at least one of amorphous silicon oxide, titanium oxide, or aluminum oxide.

[0014] And / or, the silicon oxide layer is formed by heat treatment and curing of an organosilicon resin, the material of which includes silicon dioxide.

[0015] And / or, the alloy powder substrate is a spherical powder with a D50 particle size of 1-10 μm.

[0016] And / or, the average thickness of the iron-nitrogen layer is 20-40 nm, and the hardness is 1000-2000 HV.

[0017] And / or, the average thickness of the insulating layer is 5-30 nm.

[0018] And / or, the average thickness of the silicon oxide layer is 15-30 nm.

[0019] In a second aspect, the present invention provides a method for preparing soft magnetic alloy powder as described in the first aspect, comprising the following steps:

[0020] (1) The alloy powder substrate is subjected to nitriding treatment to obtain a first powder coated with an iron-nitrogen layer;

[0021] (2) The first powder, anhydrous ethanol, inorganic oxide precursor, deionized water and ammonia water are mixed and coated. After solid-liquid separation, the powder is dried to obtain the second powder coated with an insulating layer.

[0022] (3) Mix the second powder, organosilicon resin and organic solvent, and stir under heating conditions until the organic solvent is completely evaporated to obtain soft magnetic alloy powder coated with silicon oxide layer.

[0023] And / or, the nitriding treatment in step (1) is carried out in ammonia or ammonia-nitrogen mixture, and the volume ratio of ammonia to nitrogen in the ammonia-nitrogen mixture is 1:(0.1-4).

[0024] And / or, the nitriding treatment in step (1) is performed at a temperature of 300-600°C.

[0025] And / or, the nitriding treatment in step (1) takes 30-120 min.

[0026] And / or, the coating process in step (2) includes: dispersing the first powder in anhydrous ethanol and stirring, then adding an inorganic oxide precursor, deionized water and ammonia water in sequence and stirring.

[0027] The mass ratio of the anhydrous ethanol to the first powder is (40-60):100.

[0028] And / or, the inorganic oxide precursor includes at least one of tetraethyl orthosilicate, tetrabutyl titanate, or aluminum nitrate.

[0029] And / or, the mixing mass ratio of the inorganic oxide precursor and the first powder is (0.25-2):100.

[0030] And / or, the mass ratio of the deionized water to the first powder is (8-12):100.

[0031] And / or, the mass ratio of the ammonia water to the first powder is (3-5):100.

[0032] And / or, the stirring time is 5-10 minutes, and the stirring time is 2-6 hours.

[0033] And / or, the drying temperature in step (2) is 50-70°C.

[0034] And / or, the mixing method described in step (3) includes: dissolving the silicone resin in an organic solvent, and then adding the second powder.

[0035] The organic solvent includes acetone.

[0036] And / or, the mass ratio of the silicone resin and the second powder is (0.5-2):100.

[0037] And / or, the mixing mass ratio of the organic solvent and the second powder is (15-25):100.

[0038] And / or, the temperature of the heating conditions is 50-70°C.

[0039] Thirdly, the present invention provides a soft magnetic alloy inductor, which is prepared by using soft magnetic alloy powder as described in the first aspect, including sequential ball milling, granulation, pressing and molding, and heat treatment.

[0040] And / or, the ball milling mixing includes: adding soft magnetic alloy powder, binder, ball milling media and solvent into a ball milling jar for ball milling mixing, wherein the ball milling mixing speed is 200-350 rpm and the time is 4-12 h.

[0041] The adhesive includes polyacrylate and / or polyvinyl butyral.

[0042] And / or, the milling media include zirconium balls and / or stainless steel balls.

[0043] And / or, the solvent includes anhydrous ethanol and / or ethyl acetate.

[0044] And / or, the granulation method includes spray granulation, and the resulting particles have an average particle size of 60-300 mesh.

[0045] And / or, the applied pressure during the compression molding is 1800-2000 MPa.

[0046] And / or, the heat treatment is carried out in a protective gas, and the protective gas includes at least one of nitrogen, argon or hydrogen.

[0047] And / or, the heat treatment temperature is 550-750℃, and the time is ≤60min.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The soft magnetic alloy powder provided by this invention has a composite coating structure of "iron-nitrogen layer + insulating layer + silicon oxide layer". The iron-nitrogen layer, due to its high hardness, significantly improves the wear resistance and impact resistance of the iron-based magnetic powder, exhibiting minimal morphological change and no performance degradation after ball milling. The insulating layer, with its high resistivity, effectively blocks eddy current paths between particles, optimizing the high-frequency characteristics of the material. The outermost silicon oxide layer effectively protects the inner brittle insulating layer, preventing it from detaching and being damaged during ball milling. Therefore, the above three-layer composite coating structure achieves synergistic optimization of wear resistance and magnetoelectric properties, fully meeting the performance requirements of high-frequency operation, integration, and high power density. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the soft magnetic alloy powder structure provided by the present invention.

[0051] Figure 2 These are micrographs of the soft magnetic alloy powders obtained in Example 1 and Comparative Example 1 after ball milling.

[0052] Wherein: 1-alloy powder substrate; 2-iron nitrogen layer; 3-insulating layer; 4-silicon oxide layer. Detailed Implementation

[0053] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0054] One embodiment of the present invention provides a soft magnetic alloy powder with a composite coating structure, comprising an alloy powder substrate and an iron-nitrogen layer, an insulating layer, and a silicon oxide layer sequentially coated on the surface of the alloy powder substrate from the inside out.

[0055] The alloy powder substrate includes metallic iron and / or iron-based alloys.

[0056] The soft magnetic alloy powder provided by this invention has a composite coating structure of "iron-nitrogen layer + insulating layer + silicon oxide layer". The iron-nitrogen layer, due to its high hardness, significantly improves the wear resistance and impact resistance of the iron-based magnetic powder, exhibiting minimal morphological change and no performance degradation after ball milling. The insulating layer, with its high resistivity, effectively blocks eddy current paths between particles, optimizing the high-frequency characteristics of the material. The outermost silicon oxide layer effectively protects the inner brittle insulating layer, preventing it from detaching and being damaged during ball milling. Therefore, the above three-layer composite coating structure achieves synergistic optimization of wear resistance and magnetoelectric properties, fully meeting the performance requirements of high-frequency operation, integration, and high power density.

[0057] In some embodiments, the alloy powder substrate includes at least one of Fe, FeSi, FeSiAl, FeSiCr, FeNi, FeNiMo, FeCo, or FeCoNi.

[0058] In some embodiments, the nitrogen content in the soft magnetic alloy powder is 0.1-0.5 wt%, for example, it can be 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0059] In some embodiments, the insulating layer is made of inorganic oxide, including at least one of amorphous silicon oxide, titanium oxide, or aluminum oxide.

[0060] In some embodiments, the silicon oxide layer is formed by heat treatment and curing of an organosilicon resin, and the material includes silicon dioxide.

[0061] In some embodiments, the alloy powder substrate is a spherical powder with a D50 particle size of 1-10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] In some embodiments, the average thickness of the iron-nitrogen layer is 20-40 nm, for example, it can be 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm, 36 nm, 38 nm or 40 nm, and the hardness is 1000-2000 HV, for example, it can be 1000 HV, 1100 HV, 1200 HV, 1300 HV, 1400 HV, 1500 HV, 1600 HV, 1700 HV, 1800 HV, 1900 HV or 2000 HV, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0063] In some embodiments, the average thickness of the insulating layer is 5-30 nm, for example, it can be 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm or 30 nm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0064] In some embodiments, the average thickness of the silicon oxide layer is 15-30 nm, for example, it can be 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm or 30 nm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0065] This invention, through effective control of the thickness of each coating layer, enables soft magnetic alloy powder to exhibit high hardness while simultaneously exhibiting advantages such as low hysteresis loss, low eddy current loss, and high resistivity. The soft magnetic alloy inductor made from the high-performance wear-resistant soft magnetic alloy powder provided by this invention combines high hardness, high permeability (μ > 30), high frequency stability (permeability does not decline within 1MHz), high resistance (> 2GΩ), and low high-frequency loss (< 2000kW / m). 3 The characteristics of ).

[0066] One embodiment of the present invention also provides a method for preparing the soft magnetic alloy powder described in any of the above embodiments, comprising the following steps:

[0067] (1) The alloy powder substrate is subjected to nitriding treatment to obtain a first powder coated with an iron-nitrogen layer;

[0068] (2) The first powder, anhydrous ethanol, inorganic oxide precursor, deionized water and ammonia water are mixed and coated. After solid-liquid separation, the powder is dried to obtain the second powder coated with an insulating layer.

[0069] (3) Mix the second powder, organosilicon resin and organic solvent, and stir under heating conditions until the organic solvent is completely evaporated to obtain soft magnetic alloy powder coated with silicon oxide layer.

[0070] In some embodiments, the nitriding treatment in step (1) is carried out in ammonia or an ammonia-nitrogen mixture, and the volume ratio of ammonia to nitrogen in the ammonia-nitrogen mixture is 1:(0.1-4), for example, it can be 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5 or 1:4, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0071] In some embodiments, the nitriding temperature in step (1) is 300-600°C, for example, it can be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C or 600°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0072] In some embodiments, the nitriding time in step (1) is 30-120 min, for example, it can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0073] In some embodiments, the coating process in step (2) includes: dispersing the first powder in anhydrous ethanol and stirring it, then adding an inorganic oxide precursor, deionized water and ammonia water in sequence and stirring it further.

[0074] In some embodiments, the mass ratio of the anhydrous ethanol to the first powder is (40-60):100, for example, it can be 40:100, 42:100, 44:100, 46:100, 48:100, 50:100, 52:100, 54:100, 56:100, 58:100 or 60:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0075] In some embodiments, the inorganic oxide precursor includes at least one of tetraethyl orthosilicate, tetrabutyl titanate, or aluminum nitrate.

[0076] In some embodiments, the mixing mass ratio of the inorganic oxide precursor and the first powder is (0.25-2):100, for example, it can be 0.25:100, 0.5:100, 0.75:100, 1:100, 1.25:100, 1.5:100, 1.75:100 or 2:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0077] In some embodiments, the mass ratio of the deionized water to the first powder is (8-12):100, for example, it can be 8:100, 8.5:100, 9:100, 9.5:100, 10:100, 10.5:100, 11:100, 11.5:100 or 12:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0078] In some embodiments, the mass ratio of the ammonia water to the first powder is (3-5):100, for example, it can be 3:100, 3.2:100, 3.4:100, 3.6:100, 3.8:100, 4:100, 4.2:100, 4.4:100, 4.6:100, 4.8:100 or 5:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0079] In some embodiments, the stirring time is 5-10 min, for example, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, and the continued stirring time is 2-6 h, for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h or 6 h, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0080] In some embodiments, the drying temperature in step (2) is 50-70°C, for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C or 70°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0081] In some embodiments, the mixing method in step (3) includes dissolving the silicone resin in an organic solvent and then adding the second powder.

[0082] In some embodiments, the organic solvent includes acetone.

[0083] In some embodiments, the mixing mass ratio of the silicone resin and the second powder is (0.5-2):100, for example, it can be 0.5:100, 0.6:100, 0.8:100, 1:100, 1.2:100, 1.4:100, 1.6:100, 1.8:100 or 2:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0084] In some embodiments, the mixing mass ratio of the organic solvent and the second powder is (15-25):100, for example, it can be 15:100, 16:100, 17:100, 18:100, 19:100, 20:100, 21:100, 22:100, 23:100, 24:100 or 25:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0085] In some embodiments, the heating conditions are 50-70°C, for example, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C or 70°C, but are not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0086] One embodiment of the present invention also provides a soft magnetic alloy inductor, which is prepared using the soft magnetic alloy powder described in any of the above embodiments, including sequential ball milling, granulation, pressing and molding, and heat treatment.

[0087] The soft magnetic alloy inductor provided by this invention can be applied to electronic devices such as converters, transformers, or inductors. For example, an inductor made from the soft magnetic alloy powder provided in a certain embodiment can be applied to communication electronics with special raw material processing methods and high performance requirements, so that the raw materials are not damaged during processing, while also taking into account the characteristics of low high-frequency loss, high permeability, and high resistance of the inductor.

[0088] In some embodiments, the ball milling mixing includes: adding soft magnetic alloy powder, binder, ball milling media and solvent into a ball milling jar for ball milling mixing. The ball milling mixing speed is 200-350 rpm, for example, 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, 300 rpm, 310 rpm, 320 rpm, 330 rpm, 340 rpm or 350 rpm, and the time is 4-12 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0089] In some embodiments, the binder comprises polyacrylate and / or polyvinyl butyral, and the mixing mass ratio of the binder and the soft magnetic alloy powder is (0.3-2.5):100, for example, 0.3:100, 0.5:100, 1:100, 1.5:100, 2:100 or 2.5:100, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0090] In some embodiments, the milling media comprises zirconium balls and / or stainless steel balls, and the mixing mass ratio of the milling media and the soft magnetic alloy powder is (0.5-1.5):1, for example, it can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0091] In some embodiments, the solvent includes anhydrous ethanol and / or ethyl acetate, and the mass ratio of the solvent to the soft magnetic alloy powder is (20-30):100, for example, it can be 20:100, 21:100, 22:100, 23:100, 24:100, 25:100, 26:100, 27:100, 28:100, 29:100 or 30:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0092] In some embodiments, the granulation method includes spray granulation, and the average particle size of the resulting particles is 60-300 mesh, for example, 60 mesh, 80 mesh, 100 mesh, 120 mesh, 140 mesh, 160 mesh, 180 mesh, 200 mesh, 220 mesh, 240 mesh, 260 mesh, 280 mesh or 300 mesh, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0093] In some embodiments, the applied pressure for compression molding is 1800-2000 MPa, for example, it can be 1800 MPa, 1820 MPa, 1840 MPa, 1860 MPa, 1880 MPa, 1900 MPa, 1920 MPa, 1940 MPa, 1960 MPa, 1980 MPa or 2000 MPa, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0094] In some embodiments, the heat treatment is carried out in a protective gas, and the protective gas includes at least one of nitrogen, argon, or hydrogen.

[0095] In some embodiments, the heat treatment temperature is 550-750°C, for example, it can be 550°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 740°C or 750°C, and the time is ≤60 min, for example, it can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0096] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0097] Example 1

[0098] This embodiment provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Figure 1 As shown, the soft magnetic alloy powder includes an alloy powder substrate 1 and, from the inside out, an iron-nitrogen layer 2, an insulating layer 3, and a silicon oxide layer 4 sequentially coating the surface of the alloy powder substrate 1. The alloy powder substrate 1 is an FeNi alloy with a D50 of 5 μm; the iron-nitrogen layer 2 has an average thickness of 28 nm and a nitrogen content of 0.18 wt% in the soft magnetic alloy powder; the insulating layer 3 is made of titanium oxide and has an average thickness of 15 nm; the silicon oxide layer 4 has an average thickness of 21 nm.

[0099] The soft magnetic alloy inductor provided in this embodiment is prepared by the following method, the specific steps of which include:

[0100] (1) The FeNi alloy powder was nitrided in a pure ammonia atmosphere, the nitriding temperature was controlled at 400℃ and the holding time was 60min, and the first powder coated with iron-nitrogen layer 2 was obtained.

[0101] (2) Disperse 200g of the first powder in 100g of anhydrous ethanol and stir mechanically for 10min. Then add 0.5g of tetrabutyl titanate, 20g of deionized water and 8g of ammonia in sequence. Continue stirring for 4h and then filter. Dry the obtained powder at 60℃ to obtain the second powder coated with insulating layer 3.

[0102] (3) Dissolve 1g of organosilicon resin in 40g of acetone, then add 200g of the second powder, and stir at 60°C until the acetone is completely evaporated to obtain a soft magnetic alloy powder coated with silicon oxide layer 4.

[0103] (4) 200g of soft magnetic alloy powder, 4g of polyvinyl butyral, 200g of zirconium balls and 50g of anhydrous ethanol were added to the ball mill jar in sequence and ball milled at 200rpm for 8h to obtain a mixed slurry.

[0104] (5) Spray granulation is performed on the mixed slurry obtained by ball milling to obtain material particles with an average particle size of 120 mesh;

[0105] (6) The material particles obtained by spray granulation are pressed into ring-shaped preforms at 1800 MPa using a fully automatic tablet press;

[0106] (7) The ring-shaped blank is heat-treated in a nitrogen atmosphere, the heat treatment temperature is controlled at 650℃ and the holding time is 40min to obtain a soft magnetic alloy inductor.

[0107] Example 2

[0108] This embodiment provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Figure 1As shown, the soft magnetic alloy powder includes an alloy powder substrate 1 and, from the inside out, an iron-nitrogen layer 2, an insulating layer 3, and a silicon oxide layer 4 sequentially coating the surface of the alloy powder substrate 1. The alloy powder substrate 1 is a FeNiMo alloy with a D50 of 3 μm; the iron-nitrogen layer 2 has an average thickness of 35 nm and a nitrogen content of 0.36 wt% in the soft magnetic alloy powder; the insulating layer 3 is made of titanium oxide and has an average thickness of 18 nm; and the silicon oxide layer 4 has an average thickness of 22 nm.

[0109] The soft magnetic alloy inductor provided in this embodiment is prepared by the following method, the specific steps of which include:

[0110] (1) The FeNiMo alloy powder was nitrided in a pure ammonia atmosphere, the nitriding temperature was controlled at 450℃ and the holding time was 90min, and the first powder coated with iron-nitrogen layer 2 was obtained.

[0111] (2) Disperse 200g of the first powder in 100g of anhydrous ethanol and stir mechanically for 10min. Then add 1g of tetrabutyl titanate, 20g of deionized water and 8g of ammonia in sequence. Continue stirring for 3h and then filter. Dry the obtained powder at 60℃ to obtain the second powder coated with insulating layer 3.

[0112] (3) Dissolve 2g of organosilicon resin in 40g of acetone, then add 200g of the second powder, and stir at 60°C until the acetone is completely evaporated to obtain a soft magnetic alloy powder coated with silicon oxide layer 4.

[0113] (4) 200g of soft magnetic alloy powder, 4g of polyvinyl butyral, 200g of stainless steel balls and 50g of anhydrous ethanol were added to the ball mill jar in sequence and ball milled at 250rpm for 4h to obtain a mixed slurry.

[0114] (5) Spray granulation is performed on the mixed slurry obtained by ball milling to obtain material particles with an average particle size of 120 mesh;

[0115] (6) The material particles obtained by spray granulation are pressed into ring-shaped preforms at 2000 MPa using a fully automatic tablet press;

[0116] (7) The ring-shaped blank is heat-treated in an argon atmosphere. The heat treatment temperature is controlled at 600℃ and the holding time is 60min to obtain a soft magnetic alloy inductor.

[0117] Example 3

[0118] This embodiment provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Figure 1As shown, the soft magnetic alloy powder includes an alloy powder substrate 1 and, from the inside out, an iron-nitrogen layer 2, an insulating layer 3, and a silicon oxide layer 4 sequentially coating the surface of the alloy powder substrate 1. The alloy powder substrate 1 is a FeSiAl alloy with a D50 of 5 μm; the iron-nitrogen layer 2 has an average thickness of 23 nm and a nitrogen content of 0.11 wt% in the soft magnetic alloy powder; the insulating layer 3 is made of titanium oxide and has an average thickness of 10 nm; the silicon oxide layer 4 has an average thickness of 28 nm.

[0119] The soft magnetic alloy inductor provided in this embodiment is prepared by the following method, the specific steps of which include:

[0120] (1) The FeSiAl alloy powder was nitrided in an atmosphere of ammonia and nitrogen mixture (the volume ratio of ammonia and nitrogen was 1:2), the nitriding temperature was controlled at 500℃ and the holding time was 60min, and the first powder coated with iron-nitrogen layer 2 was obtained.

[0121] (2) Disperse 200g of the first powder in 100g of anhydrous ethanol and stir mechanically for 10min. Then add 2g of tetrabutyl titanate, 20g of deionized water and 8g of ammonia in sequence. Continue stirring for 4h and then filter. Dry the obtained powder at 60℃ to obtain the second powder coated with insulating layer 3.

[0122] (3) Dissolve 3g of organosilicon resin in 40g of acetone, then add 200g of the second powder, and stir at 60°C until the acetone is completely evaporated to obtain a soft magnetic alloy powder coated with silicon oxide layer 4.

[0123] (4) 200g of soft magnetic alloy powder, 3g of polyacrylate, 200g of zirconium balls and 50g of ethyl acetate were added to a ball mill jar in sequence and ball milled at 200 rpm for 8 hours to obtain a mixed slurry.

[0124] (5) Spray granulation is performed on the mixed slurry obtained by ball milling to obtain material particles with an average particle size of 120 mesh;

[0125] (6) The material particles obtained by spray granulation are pressed into ring-shaped preforms at 1800 MPa using a fully automatic tablet press;

[0126] (7) The ring-shaped blank is heat-treated in a nitrogen atmosphere, the heat treatment temperature is controlled at 700℃ and the holding time is 60min to obtain a soft magnetic alloy inductor.

[0127] Example 4

[0128] This embodiment provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Figure 1As shown, the soft magnetic alloy powder includes an alloy powder substrate 1 and, from the inside out, an iron-nitrogen layer 2, an insulating layer 3, and a silicon oxide layer 4 sequentially coating the surface of the alloy powder substrate 1. The alloy powder substrate 1 is a FeNi alloy with a D50 of 5 μm and a FeSiCr alloy with a D50 of 5 μm; the iron-nitrogen layer 2 has an average thickness of 30 nm, and the nitrogen content in the soft magnetic alloy powder is 0.20 wt%; the insulating layer 3 is made of titanium oxide and has an average thickness of 15 nm; the silicon oxide layer 4 has an average thickness of 27 nm.

[0129] The soft magnetic alloy inductor provided in this embodiment is prepared by the following method, the specific steps of which include:

[0130] (1) The FeNi alloy powder and FeSiCr alloy were nitrided in a pure ammonia atmosphere, the nitriding temperature was controlled at 550℃ and the holding time was 30min, respectively to obtain FeNi nitrided powder and FeSiCr nitrided powder coated with iron-nitrogen layer 2.

[0131] (2) 100g of FeNi nitriding powder was dispersed in 50g of anhydrous ethanol and mechanically stirred for 5min. Then, 0.5g of tetrabutyl titanate, 10g of deionized water and 4g of ammonia were added in sequence. After stirring for 4h, the mixture was filtered and the resulting powder was dried at 60℃ to obtain FeNi nitriding powder coated with insulating layer 3. 100g of FeSiCr nitriding powder was dispersed in 50g of anhydrous ethanol and mechanically stirred for 5min. Then, 1g of tetrabutyl titanate, 10g of deionized water and 4g of ammonia were added in sequence. After stirring for 2h, the mixture was filtered and the resulting powder was dried at 60℃ to obtain FeSiCr nitriding powder coated with insulating layer 3.

[0132] (3) Dissolve 1g of silicone resin in 20g of acetone, then add 100g of FeNi nitriding powder coated with insulating layer 3, and stir at 60°C until the acetone is completely evaporated to obtain FeNi soft magnetic alloy powder coated with silicon oxide layer 4; Dissolve 1g of silicone resin in 20g of acetone, then add 100g of FeSiCr nitriding powder coated with insulating layer 3, and stir at 60°C until the acetone is completely evaporated to obtain FeSiCr soft magnetic alloy powder coated with silicon oxide layer 4.

[0133] (4) 100g FeNi soft magnetic alloy powder, 100g FeSiCr soft magnetic alloy powder, 4g polyvinyl butyral, 200g zirconium balls and 50g anhydrous ethanol were added to the ball mill jar in sequence and ball milled at 350rpm for 12h to obtain a mixed slurry.

[0134] (5) Spray granulation is performed on the mixed slurry obtained by ball milling to obtain material particles with an average particle size of 120 mesh;

[0135] (6) The material particles obtained by spray granulation are pressed into ring-shaped preforms at 2000 MPa using a fully automatic tablet press;

[0136] (7) The ring-shaped blank is heat-treated in a nitrogen atmosphere, the heat treatment temperature is controlled at 730℃ and the holding time is 30min to obtain a soft magnetic alloy inductor.

[0137] Example 5

[0138] This embodiment provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Figure 1 As shown, the soft magnetic alloy powder includes an alloy powder substrate 1 and, from the inside out, an iron-nitrogen layer 2, an insulating layer 3, and a silicon oxide layer 4 sequentially coating the surface of the alloy powder substrate 1. The alloy powder substrate 1 is an FeNi alloy with a D50 of 3 μm; the iron-nitrogen layer 2 has an average thickness of 32 nm and a nitrogen content of 0.33 wt% in the soft magnetic alloy powder; the insulating layer 3 is made of amorphous silicon oxide with an average thickness of 13 nm; and the silicon oxide layer 4 has an average thickness of 18 nm.

[0139] The soft magnetic alloy inductor provided in this embodiment is prepared by the following method, the specific steps of which include:

[0140] (1) The FeNi alloy powder was nitrided in a pure ammonia atmosphere, the nitriding temperature was controlled at 400℃ and the holding time was 60min, and the first powder coated with iron-nitrogen layer 2 was obtained.

[0141] (2) Disperse 200g of the first powder in 100g of anhydrous ethanol and stir mechanically for 10min. Then add 0.5g of tetraethyl orthosilicate, 20g of deionized water and 8g of ammonia in sequence. Continue stirring for 4h and then filter. Dry the obtained powder at 60℃ to obtain the second powder coated with insulating layer 3.

[0142] (3) Dissolve 1g of organosilicon resin in 40g of acetone, then add 200g of the second powder, and stir at 60°C until the acetone is completely evaporated to obtain a soft magnetic alloy powder coated with silicon oxide layer 4.

[0143] (4) 200g of soft magnetic alloy powder, 4g of polyvinyl butyral, 200g of zirconium balls and 50g of anhydrous ethanol were added to the ball mill jar in sequence and ball milled at 200rpm for 8h to obtain a mixed slurry.

[0144] (5) Spray granulation is performed on the mixed slurry obtained by ball milling to obtain material particles with an average particle size of 120 mesh;

[0145] (6) The material particles obtained by spray granulation are pressed into ring-shaped preforms at 1800 MPa using a fully automatic tablet press;

[0146] (7) The ring-shaped blank is heat-treated in a nitrogen atmosphere, the heat treatment temperature is controlled at 650℃ and the holding time is 40min to obtain a soft magnetic alloy inductor.

[0147] Comparative Example 1

[0148] This comparative example provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Except that the nitriding treatment was not performed, i.e., the iron-nitrogen layer 2 was removed, the average thickness of the resulting insulating layer 3 was 14 nm, and the average thickness of the resulting silicon oxide layer 4 was 22 nm. The remaining structures and conditions are the same as in Example 1, and will not be described in detail here.

[0149] Comparative Example 2

[0150] This comparative example provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Except that the holding time of the nitriding treatment is changed to 4 hours, the average thickness of the resulting iron-nitrogen layer 2 is 48 nm, the nitrogen content in the soft magnetic alloy powder is 0.31 wt%, the average thickness of the resulting insulating layer 3 is 14 nm, and the average thickness of the resulting silicon oxide layer 4 is 21 nm. The remaining structures and conditions are the same as in Example 1 and will not be described in detail here.

[0151] Comparative Example 3

[0152] This comparative example provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Except that the amount of tetrabutyl titanate added is changed to 6g, the average thickness of the resulting iron-nitrogen layer 2 is 33nm, the nitrogen content in the soft magnetic alloy powder is 0.35wt%, the average thickness of the resulting insulating layer 3 is 52nm, and the average thickness of the resulting silicon oxide layer 4 is 22nm. The remaining structures and conditions are the same as in Example 2, and will not be described in detail here.

[0153] Comparative Example 4

[0154] This comparative example provides a soft magnetic alloy powder with a composite coating structure, a soft magnetic alloy inductor, and a method for preparing the same. Except that the amount of organosilicon added is changed to 0.6g, the average thickness of the resulting iron-nitrogen layer 2 is 23nm, the nitrogen content in the soft magnetic alloy powder is 0.10wt%, the average thickness of the resulting insulating layer 3 is 10nm, and the average thickness of the resulting silicon oxide layer 4 is 7nm. The remaining structures and conditions are the same as in Example 3, and will not be described in detail here.

[0155] Performance testing

[0156] (1) Micrographs of the soft magnetic alloy powders obtained in Example 1 and Comparative Example 1 after ball milling are shown in the figure. Figure 2 .

[0157] (2) The permeability, volume loss and insulation resistance of the soft magnetic alloy inductors obtained in Examples 1-5 and Comparative Examples 1-4 were tested respectively. The relevant test results are shown in Table 1 below.

[0158] Table 1

[0159]

[0160] Combination Figure 2 As shown in Table 1, the soft magnetic alloy powders obtained in Examples 1-5 exhibit superior magnetoelectric properties due to their high hardness, wear resistance, and reasonable coating structure, as well as the uniform and dense coating layer. These properties include high permeability (μ > 30), excellent frequency stability (permeability does not decline within 1 MHz), and low high-frequency loss (< 2000 kW / m). 3 The high insulation resistance is also a concern. Comparative Example 1, lacking a wear-resistant iron-nitrogen layer, experienced severe powder deformation after ball milling, and the coating layer was also damaged. Consequently, the high-frequency permeability rapidly declined, high-frequency loss increased sharply, and the insulation resistance fell below the equipment detection limit. Comparative Example 2, with an excessively thick iron-nitrogen layer, suffered a significant decrease in permeability, resulting in excessively high hysteresis loss and a corresponding increase in total loss. Comparative Example 3, with an excessively thick insulation layer, also experienced a significant decrease in permeability and an increase in total loss. Comparative Example 4, with an excessively thin silicon oxide layer, provided limited protection for the inner insulation layer. During ball milling, the coating layer structure was damaged, permeability stability decreased, insulation resistance fell below the equipment detection limit, and overall performance was poor.

[0161] Therefore, the soft magnetic alloy powder provided by this invention has a composite coating structure of "iron nitrogen layer + insulating layer + silicon oxide layer". The iron nitrogen layer, with its high hardness, significantly improves the wear resistance and impact resistance of the iron-based magnetic powder. After ball milling, the powder morphology changes little and the performance does not deteriorate. The insulating layer, with its high resistivity, effectively blocks the eddy current path between particles and optimizes the high-frequency characteristics of the material. The outermost silicon oxide layer effectively protects the inner brittle insulating layer and prevents it from falling off and being damaged during ball milling.

[0162] In short, the above three-layer composite coating structure achieves synergistic optimization of wear resistance and magnetoelectric properties, fully meeting the performance requirements of high frequency, integration, and high power density.

[0163] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A soft magnetic alloy powder with a composite coating structure, characterized in that, The soft magnetic alloy powder includes an alloy powder substrate and an iron-nitrogen layer, an insulating layer, and a silicon oxide layer that are sequentially coated on the surface of the alloy powder substrate from the inside out. The alloy powder substrate includes metallic iron and / or iron-based alloys.

2. The soft magnetic alloy powder with a composite coating structure according to claim 1, characterized in that, The alloy powder substrate includes at least one of Fe, FeSi, FeSiAl, FeSiCr, FeNi, FeNiMo, FeCo, or FeCoNi; And / or, the nitrogen content in the soft magnetic alloy powder is 0.1-0.5 wt%; And / or, the insulating layer is made of inorganic oxide, including at least one of amorphous silicon oxide, titanium oxide, or aluminum oxide; And / or, the silicon oxide layer is formed by heat treatment and curing of an organosilicon resin, the material of which includes silicon dioxide.

3. The soft magnetic alloy powder with a composite coating structure according to claim 1 or 2, characterized in that, The alloy powder substrate is a spherical powder with a D50 particle size of 1-10μm; And / or, the average thickness of the iron-nitrogen layer is 20-40 nm, and the hardness is 1000-2000 HV; And / or, the average thickness of the insulating layer is 5-30 nm; And / or, the average thickness of the silicon oxide layer is 15-30 nm.

4. A method for preparing soft magnetic alloy powder as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) The alloy powder substrate is subjected to nitriding treatment to obtain a first powder coated with an iron-nitrogen layer; (2) The first powder, anhydrous ethanol, inorganic oxide precursor, deionized water and ammonia water are mixed and coated. After solid-liquid separation, the powder is dried to obtain the second powder coated with an insulating layer. (3) Mix the second powder, organosilicon resin and organic solvent, and stir under heating conditions until the organic solvent is completely evaporated to obtain soft magnetic alloy powder coated with silicon oxide layer.

5. The method for preparing soft magnetic alloy powder according to claim 4, characterized in that, The nitriding treatment in step (1) is carried out in ammonia or ammonia-nitrogen mixture, and the volume ratio of ammonia to nitrogen in the ammonia-nitrogen mixture is 1:(0.1-4); And / or, the nitriding treatment in step (1) is performed at a temperature of 300-600°C; And / or, the nitriding treatment in step (1) takes 30-120 min.

6. The method for preparing soft magnetic alloy powder according to claim 4, characterized in that, The coating process in step (2) includes: dispersing the first powder in anhydrous ethanol and stirring it, then adding the inorganic oxide precursor, deionized water and ammonia water in sequence and stirring it. The mass ratio of the anhydrous ethanol to the first powder is (40-60):

100. And / or, the inorganic oxide precursor includes at least one of tetraethyl orthosilicate, tetrabutyl titanate, or aluminum nitrate; And / or, the mixing mass ratio of the inorganic oxide precursor and the first powder is (0.25-2):100; And / or, the mass ratio of the deionized water to the first powder is (8-12):100; And / or, the mass ratio of the ammonia water to the first powder is (3-5):100; And / or, the stirring time is 5-10 minutes, and the stirring time is 2-6 hours; And / or, the drying temperature in step (2) is 50-70°C.

7. The method for preparing soft magnetic alloy powder according to claim 4, characterized in that, The mixing method in step (3) includes: dissolving the silicone resin in an organic solvent, and then adding the second powder; The organic solvent includes acetone; And / or, the mass ratio of the silicone resin and the second powder is (0.5-2):100; And / or, the mixing mass ratio of the organic solvent and the second powder is (15-25):100; And / or, the temperature of the heating conditions is 50-70°C.

8. A soft magnetic alloy inductor, characterized in that, The soft magnetic alloy inductor is prepared using the soft magnetic alloy powder as described in any one of claims 1-3, including sequential ball milling, granulation, pressing and molding, and heat treatment.

9. The soft magnetic alloy inductor according to claim 8, characterized in that, The ball milling mixing includes: adding soft magnetic alloy powder, binder, ball milling media and solvent into a ball milling jar for ball milling mixing, wherein the ball milling mixing speed is 200-350 rpm and the time is 4-12 h; The adhesive includes polyacrylate and / or polyvinyl butyral; And / or, the milling media include zirconium balls and / or stainless steel balls; And / or, the solvent includes anhydrous ethanol and / or ethyl acetate; And / or, the granulation method includes spray granulation, and the resulting particles have an average particle size of 60-300 mesh.

10. The soft magnetic alloy inductor according to claim 8 or 9, characterized in that, The pressure applied during the compression molding process is 1800-2000 MPa; And / or, the heat treatment is carried out in a protective gas, and the protective gas includes at least one of nitrogen, argon or hydrogen; And / or, the heat treatment temperature is 550-750℃, and the time is ≤60min.

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