Amorphous composite magnetic powder core based on argon oxygen plasma discharge modification and preparation method and application thereof

Abstract

The invention discloses an amorphous composite magnetic powder core based on argon oxygen plasma discharge modification and a preparation method and application of the amorphous composite magnetic powder core. Amorphous alloy powder is modified by designing a reasonable argon-oxygen flow rate ratio and discharge plasma, an oxide + alpha-Fe double-cluster structure is obtained on the surface layer of the amorphous alloy powder, then the modified alloy powder is subjected to insulation coating, pressing and heat treatment are conducted, and finally the amorphous composite magnetic powder core with high magnetic conductivity and low magnetic loss is obtained. The method is simple in technological process and low in cost, can be effectively popularized to various amorphous alloy soft magnetic powder, and has extremely high application value in industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft magnetic materials and relates to an amorphous magnetic powder core modified based on argon-oxygen plasma discharge, and its preparation method and application. Specifically, iron-based amorphous alloy powder is treated by discharge modification with argon-oxygen mixed gas in a specific proportion to obtain a double cluster structure of oxide + α-Fe, and then a coating agent is added for coating and then pressed and sintered to obtain an amorphous composite magnetic powder core with high magnetic permeability and low loss. Background Art

[0002] Soft magnetic composites are commonly used in electrical and electronic devices such as inductors, transformers, and motors. In recent years, applications such as new energy vehicles, 5G communications, and artificial intelligence robots have become increasingly demanding, requiring soft magnetic composites to meet the challenges of miniaturization, high frequency, lightweight, energy-efficient, and high current capabilities of their core components. Soft magnetic materials can be divided into crystalline and amorphous structures based on their crystal structure. Currently, the most widely used soft magnetic materials are crystalline, such as traditional electrical pure iron, silicon steel, permalloy, FeSiAl alloys, and ferrites. The saturation magnetic induction of amorphous alloys is lower than that of iron-cobalt alloys, pure iron, and silicon steel, but higher than that of FeSiAl and Permalloy. They also have lower coercivity and higher permeability than iron-cobalt alloys, pure iron, and silicon steel. Compared to iron-cobalt alloys, they have higher resistivity, resulting in lower eddy current losses. In summary, amorphous alloy soft magnetic materials offer a combination of high saturation magnetic induction, low coercivity, high permeability, and low losses, making them excellent soft magnetic materials.

[0003] Iron-based nanocrystalline soft magnetic alloys are a new class of soft magnetic materials characterized by the precipitation of nanometer-sized α-Fe grains within an amorphous matrix through appropriate processing of an iron-based amorphous alloy, resulting in excellent magnetic properties. Unlike traditional crystalline materials, nanocrystalline soft magnetic alloys lack grain boundaries, instead interpenetrating the grains with an amorphous matrix. The nanosized α-Fe grains are uniformly distributed within the amorphous matrix and well-integrated, resulting in the excellent soft magnetic properties of these alloys. Theoretically, the structural length of α-Fe nanocrystals is significantly shorter than the ferromagnetic exchange length, reducing the magnetocrystalline anisotropy constant and coercivity, resulting in high permeability and low losses in nanocrystalline soft magnetic alloys. Recent research indicates that oversized α-Fe nanocrystals increase magnetostriction and coercivity, while α-Fe clusters, smaller than the nanocrystal size, minimize magnetostriction and coercivity, facilitating magnetic domain deflection and thus improving permeability while reducing hysteresis losses. Therefore, introducing α-Fe clusters (α-Fe smaller than 10 nm) into amorphous alloy soft magnetic materials has become one of the effective means to improve their soft magnetic properties.

[0004] The high-frequency, low-loss characteristics of amorphous alloy powder core devices are key advantages for their breakthrough applications in modern power electronics. The losses in powder cores are primarily related to hysteresis loss and eddy current loss. Hysteresis loss is primarily reduced through high-temperature annealing to release internal stress and the formation of α-Fe nanocrystals in the amorphous alloy to reduce magnetostriction. Eddy current loss is primarily achieved through oxide and insulating resin coating. Oxides (Al2O3, SiO2, Fe3O4, Fe2O3) are resistant to high temperatures and have high resistivity, but they have poor adhesion to powders, making them susceptible to cracking during subsequent pressing. While polymer resins such as silicone resins and epoxy resins have good adhesion to powders, they are not resistant to high temperatures, making it difficult to effectively release internal stress through high-temperature annealing.

[0005] In summary, if α-Fe clusters and oxide coatings can be introduced into amorphous alloy magnetic powder cores at the same time, the improvement of magnetic permeability and the reduction of hysteresis loss and eddy current loss will be achieved at the same time, which will greatly promote the engineering of amorphous alloy magnetic powder cores. At present, there are no research reports on the simultaneous introduction of α-Fe clusters and oxide coatings into amorphous alloy magnetic powder cores. In view of this, the present invention obtains an oxide + α-Fe double cluster structure by regulating the ratio of argon and oxygen gases. Compared with comparative example 1, the magnetic permeability is increased by 38%, the total loss is reduced by 34%, of which the hysteresis loss is reduced by 25%, and the eddy current loss is reduced by 38%. The present invention effectively solves the common problem of difficulty in improving the magnetic permeability of magnetic powder cores while reducing hysteresis loss and eddy current loss, and will greatly expand the application field of iron-based amorphous alloy magnetic powder cores. Summary of the Invention

[0006] In order to address the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing an amorphous magnetic powder core modified by argon-oxygen plasma discharge. The method is specifically to place soft magnetic amorphous alloy powder in a stainless steel ball mill without grinding balls, evacuate and introduce a mixed atmosphere of argon and oxygen, bombard the powder with high energy of argon-oxygen ions, and instantaneously increase the temperature in the local micro-region, causing oxygen to form oxide clusters with Fe and Si elements on the surface of the iron-based amorphous alloy powder, which act as nucleation points for the formation of α-Fe clusters, thereby forming a double cluster structure of oxide + α-Fe on the surface of the amorphous alloy powder. The modified powder is mixed and coated with an insulating agent, and subjected to compression molding and heat treatment to finally obtain an amorphous alloy magnetic powder core with high magnetic permeability and low loss.

[0007] Another object of the present invention is to provide an amorphous magnetic powder core modified by argon-oxygen plasma discharge, which is prepared by the above method.

[0008] Another object of the present invention is to provide the application of the above-mentioned amorphous magnetic powder core modified by argon-oxygen plasma discharge in electronic devices in the medium and high frequency fields.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] An amorphous composite magnetic powder core with an oxide + α-Fe double cluster structure has a powder size of 2 to 80 μm and a powder surface with a double cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the insulating shell composed of the oxide and α-Fe double clusters has a thickness of 5 to 50 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 1 to 7 nm, and the α-Fe cluster size is 2 to 9 nm.

[0011] The above-mentioned amorphous composite magnetic powder core of oxide + α-Fe double cluster structure is prepared by the following method:

[0012] The amorphous alloy powder is modified by discharge plasma in a mixed gas atmosphere of argon and oxygen, mixed with insulating resin and coated, and then pressed and heat-treated to obtain a composite magnetic powder core.

[0013] Preferably, the average particle size of the amorphous alloy powder is 10-80 μm, more preferably 10-60 μm, most preferably 30-60 μm; the minimum particle size is 5-20 μm, more preferably 2-12 μm, most preferably 5-12 μm.

[0014] Preferably, the amorphous alloy powder is at least one of FeSiBC, FeSiB and FeSiBCrC; more preferably Fe 78 Si 10 B 10 C2、Fe 76 Si 12 B 12 and Fe 73.7 Si 11 B 11 Cr 2.3 At least one of C2; more preferably Fe 78 Si 10 B 10 C2 and Fe 73.7 Si 11 B 11 Cr 2.3 At least one of C2; most preferably Fe 78 Si 10 B 10 C2.

[0015] Preferably, the flow rate ratio of argon to oxygen is 10:(2-4), more preferably 10:3.

[0016] Preferably, the pressure of the mixed gas of argon and oxygen is 0.05-0.5 MPa; more preferably 0.1-0.5 MPa.

[0017] Preferably, the discharge plasma modification treatment in a mixed gas atmosphere of argon and oxygen is carried out in a stainless steel ball mill without grinding balls, and argon and oxygen are introduced into the stainless steel ball mill at a flow rate of 10: (2-4) so that the pressure of the mixed gas in the ball mill is 0.05-0.5 MPa.

[0018] Preferably, the discharge plasma modification treatment time is 0.25 to 1.25 h; more preferably 0.45 to 1 h; most preferably 0.5 to 1 h.

[0019] Preferably, the parameters of the discharge plasma modification treatment are: frequency 5-9kHz, current 90-110mA, voltage 4-5kV, power 400-500W, and motor speed 500-1300rpm; more preferably, the parameters are: frequency 7.5-8kHz, current 100-103mA, voltage 4.2-4.5kV, power 430-470W, and motor speed 900-1000rpm.

[0020] Preferably, the insulating resin is at least one of silicone resin, phenolic resin and epoxy modified resin.

[0021] Preferably, the mass ratio of the amorphous alloy powder to the insulating resin is 100:(1-5), more preferably 100:(1-3), and most preferably 100:(1-2).

[0022] Preferably, the mixed coating method is: mixing the insulating resin and the amorphous alloy powder modified by discharge plasma, then mixing them evenly with an organic solvent, drying, and then mixing them evenly with a lubricant.

[0023] More preferably, the organic solvent is at least one of acetone and anhydrous ethanol, and the mass ratio of the organic solvent to the mixed powder is 15-25:85-75; more preferably 15-20:80-75.

[0024] More preferably, the lubricant is zinc stearate, and the mass ratio of the lubricant to the mixed powder is 0.5 to 1:100.

[0025] Preferably, the pressure of the press molding is 1200-2000 MPa, more preferably 1200-1700 MPa; the holding time is 5-10 s, more preferably 5-6 s.

[0026] Preferably, the heat treatment temperature is 380-480° C.; more preferably 400-450° C.; and the heat treatment time is 0.5-3 h; more preferably 0.5-1 h.

[0027] Preferably, the heat treatment is performed under a vacuum environment.

[0028] The method for preparing the above-mentioned amorphous composite magnetic powder core having an oxide + α-Fe double cluster structure comprises the following steps:

[0029] (1) treating the amorphous alloy powder with a discharge plasma in a mixed gas atmosphere of argon and oxygen, and then mixing and coating the powder with an insulating resin to obtain a coated amorphous alloy composite powder;

[0030] (2) The coated amorphous alloy composite powder is mixed with a lubricant, and then pressed and heat-treated to obtain a composite magnetic powder core.

[0031] Preferably, the amorphous alloy powder in step (1) is at least one of FeSiBC, FeSiB and FeSiBCrC; more preferably Fe 78 Si 10 B 10 C2、Fe 76 Si 12 B 12 and Fe 73.7 Si 11 B 11 Cr 2.3 At least one of C2; more preferably Fe 78 Si 10 B 10 C2 and Fe 73.7 Si 11 B 11 Cr 2.3 At least one of C2; most preferably Fe 78 Si 10 B 10 C2.

[0032] Preferably, the average particle size of the amorphous alloy powder in step (1) is 10 to 80 μm, more preferably 10 to 60 μm, and most preferably 30 to 60 μm; the minimum particle size is 5 to 20 μm, more preferably 2 to 12 μm, and most preferably 5 to 12 μm.

[0033] Preferably, the mass ratio of the amorphous alloy powder to the insulating resin in step (1) is 100:(1-5), more preferably 100:(1-3); and most preferably 100:(1-2).

[0034] Preferably, the insulating resin in step (1) is at least one of silicone resin, phenolic resin and epoxy modified resin.

[0035] Preferably, the pressure of the mixed gas of argon and oxygen in step (1) is 0.05 to 0.5 MPa; more preferably 0.1 to 0.5 MPa.

[0036] Preferably, the flow rate ratio of argon to oxygen in step (1) is 10:(2-4), more preferably 10:3.

[0037] Preferably, the discharge plasma modification treatment in step (1) in a mixed gas atmosphere of argon and oxygen is carried out in a stainless steel ball mill without grinding balls, and argon and oxygen are introduced into the stainless steel ball mill at a flow rate of 10: (2-4) so that the pressure of the mixed gas in the ball mill is 0.05-0.5 MPa.

[0038] Preferably, the duration of the discharge plasma modification treatment in step (1) is 0.25 to 1.25 h; more preferably 0.45 to 1 h; most preferably 0.5 to 1 h.

[0039] Preferably, the parameters of the discharge plasma modification treatment in step (1) are: frequency 5-9 kHz, current 90-110 mA, voltage 4-5 kV, power 400-500 W, and motor speed 500-1300 rpm; more preferably: frequency 7.5-8 kHz, current 100-103 mA, voltage 4.2-4.5 kV, power 430-470 W, and motor speed 900-1000 rpm.

[0040] Preferably, the mixed coating method in step (1) is: mixing the insulating resin and the amorphous alloy powder modified by discharge plasma, then mixing them evenly with an organic solvent, drying, and then adding zinc stearate and mixing evenly.

[0041] More preferably, the organic solvent is at least one of acetone and anhydrous ethanol, and the mass ratio of the organic solvent to the mixed powder is 15-25:85-75; more preferably 15-20:80-75.

[0042] Preferably, the lubricant in step (2) is zinc stearate, and the mass ratio of the lubricant to the coated amorphous alloy powder is 0.5 to 1:100.

[0043] Preferably, the pressure of the compression molding in step (2) is 1200-2000 MPa, more preferably 1200-1700 MPa; the holding time is 5-10 s, more preferably 5-6 s.

[0044] Preferably, the temperature of the heat treatment in step (3) is 380-480°C; more preferably 400-450°C; and the time is 0.5-3h; more preferably 0.5-1h.

[0045] The application of the above-mentioned amorphous composite magnetic powder core with an oxide + α-Fe double cluster structure in the preparation of inductor components.

[0046] Preferably, the application fields of the inductive components are 5G communications, solar charging panels, 5G base stations, new energy vehicles, car charging piles, home appliances, airborne power systems, industrial inverters, satellite communications, switching power supplies, photovoltaic inverters and other fields.

[0047] More preferably, the 5G communication refers to 5G mobile phone communication.

[0048] The present invention is based on the mechanism of argon-oxygen plasma discharge modification of amorphous magnetic powder cores: during the discharge process, argon-oxygen plasma bombards the powder with high energy, causing the micro-region on the surface of the powder to be instantaneously high in temperature. At the same time, oxygen forms oxide clusters (SiO2, Fe2O3 and Fe3O4) with Fe and Si elements in the surface layer of the iron-based amorphous alloy powder, which act as nucleation points for α-Fe clusters, ultimately obtaining a double cluster structure of oxide + α-Fe, resulting in increased magnetic permeability and reduced magnetic loss. At the same time, the discharge plasma can effectively disperse powder agglomerations and eliminate satellite balls and hollow balls, thereby improving the fluidity of the coated composite powder and increasing the density of the composite magnetic powder core, thereby achieving the purpose of increasing magnetic permeability and reducing magnetic loss.

[0049] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0050] (1) The present invention obtains a double cluster structure of oxide + α-Fe by regulating the argon-oxygen ratio, which can minimize the magnetostriction of the alloy, reduce the coercive force, and facilitate the deflection of the magnetic domain, thereby improving the magnetic permeability of the composite magnetic powder core and reducing its magnetic loss.

[0051] (2) The amorphous powder modified by plasma discharge of the present invention has better fluidity, and the composite magnetic powder core prepared by the coated powder has lower porosity and higher density, thereby improving the magnetic permeability of the composite magnetic powder core.

[0052] (3) Compared with composite magnetic powder cores without discharge modification treatment of amorphous powder and other argon-oxygen ratios, the magnetic permeability of the composite magnetic powder cores obtained by the present invention is increased by 27-38%, while the magnetic loss is reduced by 25-34%.

[0053] (4) The amorphous composite magnetic powder core modified by argon-oxygen plasma discharge of the present invention can be widely applied to various amorphous alloy powders. The process is simple, environmentally friendly, and low-cost. At the same time, it can significantly improve the magnetic permeability and reduce the magnetic loss, achieving a balance of comprehensive soft magnetic properties, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram of the organizational structure of the amorphous alloy composite powder after argon-oxygen plasma discharge modification and coating in the present invention.

[0055] Figure 2This is a transmission electron micrograph of the surface of the amorphous alloy powder after argon-oxygen plasma discharge modification in Example 1 of the present invention. As can be seen, the powder surface has a double-cluster structure consisting of oxides and α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the insulating shell formed by the oxide and α-Fe double clusters has an average thickness of 15 nm; the oxide species are SiO2, Fe2O3, and Fe3O4; the oxide clusters are 2 nm in size; and the α-Fe clusters are 4 nm in size.

[0056] Figure 3 1 is a comparison chart of the magnetic permeabilities of the composite magnetic powder cores corresponding to Examples 1, 4, and 5 and Comparative Examples 1, 4 to 6.

[0057] Figure 4 1 is a comparison chart of the magnetic losses of the composite magnetic powder cores corresponding to Examples 1, 4, and 5 and Comparative Examples 1, 4 to 6.

[0058] Figure 5 1 is a comparison chart of hysteresis loss and eddy current loss between Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0059] The present invention will be described in further detail below with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0060] In the examples of the present invention, if the specific conditions are not specified, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. All raw materials and reagents used without specifying the manufacturer are conventional products that can be purchased from the market.

[0061] Example 1

[0062] (1) Preparation before discharge treatment: Fe 78 Si 10 B 10 The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:3 to achieve an atmosphere pressure of 0.1 MPa.

[0063] (2) Discharge modification treatment: The specific discharge parameters are: frequency 7.5 kHz, current 100 mA, voltage 4.2 kV, power 430 W, motor speed 900 rpm, and discharge time 0.5 h.

[0064] (3) Powder coating: The modified powder from step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:2. The mixed powder was then mixed with acetone at a mass ratio of 80:20 and stirred for 45 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 80°C for 1 hour. Finally, 0.5 wt.% (based on the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 2 hours.

[0065] (4) Compression molding: The mixed powder is pressed into a magnetic powder core green body at a pressure of 1200 MPa for 6 seconds.

[0066] (5) Heat treatment annealing: anneal the green body at 400°C for 0.5h in a vacuum environment to obtain a composite magnetic powder core.

[0067] The composite magnetic powder core obtained in this embodiment has a powder size of 5 to 80 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 10 to 20 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 1 to 4 nm; the α-Fe cluster size is 2 to 6 nm.

[0068] Example 2

[0069] (1) Preparation before discharge treatment: Fe with an average particle size of 10 μm and a minimum size of 2 μm 76 Si 12 B 12 The amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:3 to achieve an atmosphere pressure of 0.5 MPa.

[0070] (2) Discharge modification treatment: The specific discharge parameters are: frequency 8 kHz, current 100 mA, voltage 4.5 kV, power 450 W, motor speed 1000 rpm, and discharge time 0.45 h.

[0071] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:3. The mixed powder was then mixed with acetone at a mass ratio of 85:15 and stirred for 60 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 60°C for 2 hours. Finally, 0.5 wt% (of the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 3 hours.

[0072] (4) Compression molding: The mixed powder is pressed at a pressure of 1500 MPa for 10 seconds to form a magnetic powder core green body.

[0073] (5) Heat treatment annealing: The green body is annealed at 400°C for 0.75h in a vacuum environment to obtain a composite magnetic powder core.

[0074] The composite magnetic powder core obtained in this embodiment has a powder size of 2 to 30 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 20 to 30 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 2 to 5 nm; the α-Fe cluster size is 5 to 9 nm.

[0075] Example 3

[0076] (1) Preparation before discharge treatment: Fe with an average particle size of 30 μm and a minimum size of 12 μm 73.7 Si 11 B 11 Cr 2.3 The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:3 to achieve an atmosphere pressure of 0.5 MPa.

[0077] (2) Discharge modification treatment: The specific discharge parameters are: frequency 8 kHz, current 103 mA, voltage 4.5 kV, power 470 W, motor speed 1000 rpm, and discharge time 1 h.

[0078] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:1. The mixed powder was then mixed with acetone at a mass ratio of 75:25 and stirred for 75 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 100°C for 0.5 hours. Finally, 0.5 wt% (based on the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 3 hours.

[0079] (4) Compression molding: The mixed powder is pressed at a pressure of 1700 MPa for 10 seconds to form a magnetic powder core green body.

[0080] (5) Heat treatment annealing: anneal the green body at 400°C for 1 h in a vacuum environment to obtain a composite magnetic powder core.

[0081] The powder size of the composite magnetic powder core obtained in this embodiment is 12 to 45 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 20 to 36 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 4 to 7 nm; the α-Fe cluster size is 2 to 7 nm.

[0082] Example 4

[0083] (1) Preparation before discharge treatment: Fe with an average particle size of 60 μm and a minimum size of 5 μm 78 Si 10 B 10 The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:4 to achieve an atmosphere pressure of 0.1 MPa.

[0084] (2) Discharge modification treatment: The specific discharge parameters are: frequency 7.5kHz, current 100mA, voltage 4.2kV, power 430W, motor speed 900rpm, and discharge time 0.5h.

[0085] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:2. The mixed powder was then mixed with acetone at a mass ratio of 80:20 and stirred for 45 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 80°C for 1 hour. Finally, 0.5 wt% (of the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 2 hours.

[0086] (4) Compression molding: The mixed powder is pressed at a pressure of 1200 MPa for 6 seconds to form a magnetic powder core green body.

[0087] (5) Heat treatment annealing: anneal the green body at 400°C for 0.5h in a vacuum environment to obtain a composite magnetic powder core.

[0088] The composite magnetic powder core obtained in this embodiment has a powder size of 5 to 80 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 40 to 50 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 2 to 6 nm; the α-Fe cluster size is 5 to 9 nm.

[0089] Example 5

[0090] (1) Preparation before discharge treatment: Fe with an average particle size of 60 μm and a minimum size of 5 μm 78 Si 10 B 10 The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:2 to achieve an atmosphere pressure of 0.1 MPa.

[0091] (2) Discharge modification treatment: The specific discharge parameters are: frequency 7.5kHz, current 100mA, voltage 4.2kV, power 430W, motor speed 900rpm, and discharge time 0.5h.

[0092] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:2. The mixed powder was then mixed with acetone at a mass ratio of 80:20 and stirred for 45 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 80°C for 1 hour. Finally, 0.5 wt% (of the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 2 hours.

[0093] (4) Compression molding: The mixed powder is pressed at a pressure of 1200 MPa for 6 seconds to form a magnetic powder core green body.

[0094] (5) Heat treatment annealing: anneal the green body at 400°C for 0.5h in a vacuum environment to obtain a composite magnetic powder core.

[0095] The composite magnetic powder core obtained in this embodiment has a powder size of 5 to 80 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 5 to 15 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 2 to 6 nm; the α-Fe cluster size is 2 to 5 nm.

[0096] Comparative Example 1

[0097] Compared with Example 1, the difference is that the operations of steps (1) to (2) are not performed, and the operations of steps (3) to (5) are directly performed, that is, the plasma discharge modification treatment under the argon and oxygen atmosphere is not performed.

[0098] The composite magnetic powder core obtained in this comparative example has a powder size of 5 to 80 μm and an amorphous surface.

[0099] Comparative Example 2

[0100] Compared with Example 2, the difference is that the operations of steps (1) to (2) are not performed, and the operations of steps (3) to (5) are directly performed, that is, the plasma discharge modification treatment under argon and oxygen atmosphere is not performed.

[0101] The composite magnetic powder core obtained in this comparative example has a powder size of 2 to 30 μm and an amorphous surface.

[0102] Comparative Example 3

[0103] Compared with Example 3, the difference is that the operations of steps (1) to (2) are not performed, and the operations of steps (3) to (5) are directly performed, that is, the plasma discharge modification treatment under the argon and oxygen atmosphere is not performed.

[0104] The composite magnetic powder core obtained in this comparative example has a powder size of 12 to 45 μm, and the powder surface is amorphous.

[0105] Comparative Example 4

[0106] (1) Preparation before discharge treatment: Fe with an average particle size of 60 μm and a minimum size of 5 μm 78 Si 10 B 10 The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:0 to maintain a pressure of 0.1 MPa.

[0107] (2) Discharge modification treatment: The specific discharge parameters are: frequency 7.5kHz, current 100mA, voltage 4.2kV, power 430W, motor speed 900rpm, and discharge time 0.5h.

[0108] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:2. The mixed powder was then mixed with acetone at a mass ratio of 80:20 and stirred for 45 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 80°C for 1 hour. Finally, 0.5 wt% (of the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 2 hours.

[0109] (4) Compression molding: The mixed powder is pressed at a pressure of 1200 MPa for 6 seconds to form a magnetic powder core green body.

[0110] (5) Heat treatment annealing: anneal the green body at 400°C for 0.5h in a vacuum environment to obtain a composite magnetic powder core.

[0111] The composite magnetic powder core obtained in this comparative example has a powder size of 5 to 80 μm, a powder surface of amorphous+α-Fe, and an α-Fe cluster size of 35 to 47 nm.

[0112] Comparative Example 5

[0113] (1) Preparation before discharge treatment: Fe with an average particle size of 60 μm and a minimum size of 5 μm 78 Si 10 B 10 The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 10:5 to maintain a pressure of 0.1 MPa.

[0114] (2) Discharge modification treatment: The specific discharge parameters are: frequency 7.5kHz, current 100mA, voltage 4.2kV, power 430W, motor speed 900rpm, and discharge time 0.5h.

[0115] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:2. The mixed powder was then mixed with acetone at a mass ratio of 80:20 and stirred for 45 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 80°C for 1 hour. Finally, 0.5 wt% (of the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 2 hours.

[0116] (4) Compression molding: The mixed powder is pressed at a pressure of 1200 MPa for 6 seconds to form a magnetic powder core green body.

[0117] (5) Heat treatment annealing: anneal the green body at 400°C for 0.5h in a vacuum environment to obtain a composite magnetic powder core.

[0118] The composite magnetic powder core obtained in this comparative example has a powder size of 5 to 80 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 50 to 70 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 5 to 15 nm; the α-Fe cluster size is 15 to 27 nm.

[0119] Comparative Example 6

[0120] (1) Preparation before discharge treatment: Fe with an average particle size of 60 μm and a minimum size of 5 μm 78 Si 10 B 10The C2 amorphous alloy powder was added to a stainless steel ball mill without grinding balls. The ball mill was evacuated and argon and oxygen were introduced into the ball mill at a flow rate ratio of 0:10 to maintain a pressure of 0.1 MPa.

[0121] (2) Discharge modification treatment: The specific discharge parameters are: frequency 7.5kHz, current 100mA, voltage 4.2kV, power 430W, motor speed 900rpm, and discharge time 0.5h.

[0122] (3) Powder coating: The powder modified in step (2) was mixed with silicone resin (Yixin Chemical New Material 804) at a mass ratio of 100:2. The mixed powder was then mixed with acetone at a mass ratio of 80:20 and stirred for 45 minutes. After stirring, the mixture was dried in a drying oven at a temperature of 80°C for 1 hour. Finally, 0.5 wt% (of the mass of the mixed powder) of zinc stearate was added to the dried powder and stirred for 2 hours.

[0123] (4) Compression molding: The mixed powder is pressed at a pressure of 1200 MPa for 6 seconds to form a magnetic powder core green body.

[0124] (5) Heat treatment annealing: anneal the green body at 400°C for 0.5h in a vacuum environment to obtain a composite magnetic powder core.

[0125] The composite magnetic powder core obtained in this comparative example has a powder size of 5 to 80 μm, a powder surface of amorphous + oxide, an insulating shell thickness of the oxide of 75 to 85 nm, oxide types of SiO2, Fe2O3 and Fe3O4, and an oxide cluster size of 5 to 11 nm.

[0126] After argon-oxygen mixed discharge treatment, an oxide + α-Fe dual cluster structure is obtained. Subsequent low-temperature annealing at 400°C is used to eliminate the internal stress generated during the cold pressing process. The high permeability and low-loss magnetic powder core prepared using this method has improved soft magnetic properties.

[0127] Performance evaluation of composite magnetic powder core:

[0128] The composite magnetic powder cores prepared in the above embodiments and comparative examples were tested for density and magnetic properties.

[0129] The density test method is as follows: the density of the magnetic powder core is actually measured using the Archimedes drainage method.

[0130] The magnetic properties test method is as follows: the magnetic permeability is tested using a Tonghui TH2829C; the magnetic loss is tested using an IWATSU B-H Analyzer (SY-8219), and the test conditions are 1 MHz and 20 mT.

[0131] Table 1 Test results of soft magnetic powder cores of Examples 1 to 3 and Comparative Examples 1 to 3

[0132]

[0133]

[0134] According to the test data in Table 1:

[0135] (1) Compared with Comparative Examples 1 to 3, the composite magnetic powder cores prepared in Examples 1 to 3 have a higher density and a higher magnetic permeability, indicating that the amorphous alloy powder modified by argon-oxygen mixed discharge in Examples 1 to 3 can effectively improve the density of the composite magnetic powder cores.

[0136] (2) Compared with Comparative Examples 1 to 3, the composite magnetic powder cores prepared in Examples 1 to 3 have lower magnetic losses. This is because after the argon-oxygen mixed discharge modification treatment, a double cluster structure of oxide + α-Fe is obtained, which is beneficial for reducing hysteresis loss and eddy current loss, thereby reducing the total loss.

[0137] (3) Compared with Example 1, the nanocrystal size of Comparative Examples 4 and 5 is too large, resulting in a decrease in magnetic permeability and an increase in magnetic loss; the oxygen content in Comparative Examples 5 and 6 is high, which causes powder sintering and agglomeration, reduces the density of the magnetic powder core, reduces the magnetic permeability and increases the magnetic loss; Examples 4 and 5 have larger grain sizes than Example 1, reduce the magnetic permeability and have higher magnetic loss.

[0138] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. An amorphous composite magnetic powder core with oxide + α-Fe double cluster insulating shell, characterized by: The powder size is 2 to 80 μm, and the powder surface is a double-cluster insulating shell composed of oxide + α-Fe; the oxide clusters are dispersed between the α-Fe clusters; the thickness of the insulating shell composed of the oxide and α-Fe double clusters is 5 to 50 nm; the oxide types are SiO2, Fe2O3 and Fe3O4, the oxide cluster size is 1 to 7 nm; the α-Fe cluster size is 2 to 9 nm.

2. The method for preparing the amorphous composite magnetic powder core of oxide + α-Fe double cluster insulating shell according to claim 1, characterized in that: The following steps are involved: (1) treating the amorphous alloy powder with a discharge plasma in a mixed gas atmosphere of argon and oxygen, and then mixing and coating the powder with an insulating resin to obtain a coated amorphous alloy composite powder; (2) The coated amorphous alloy composite powder is mixed with a lubricant, and then pressed into shape and heat-treated to obtain an amorphous composite magnetic powder core.

3. The preparation method according to claim 2, characterized in that: The pressure of the mixed gas of argon and oxygen in step (1) is 0.05-0.5 MPa; And / or, the volume ratio of argon to oxygen in step (1) is 10:(2-4).

4. The preparation method according to claim 3, characterized in that The pressure of the mixed gas of argon and oxygen in step (1) is 0.1-0.5 MPa; And / or, the volume ratio of argon and oxygen in step (1) is 10:

3.

5. The preparation method according to claim 2 or 3, characterized in that: The duration of the discharge plasma modification treatment in step (1) is 0.25 to 1.25 hours; And / or, the parameters of the discharge plasma modification treatment in step (1) are: frequency 5-9 kHz, current 90-110 mA, voltage 4-5 kV, power 400-500 W, and motor speed 500-1300 rpm.

6. The preparation method according to claim 5, characterized in that: The duration of the discharge plasma modification treatment in step (1) is 0.45 to 1 hour; And / or, the parameters of the discharge plasma modification treatment in step (1) are: frequency 7.5-8 kHz, current 100-103 mA, voltage 4.2-4.5 kV, power 430-470 W, and motor speed 900-1000 rpm.

7. The preparation method according to claim 2 or 3, characterized in that The amorphous alloy powder in step (1) is at least one of iron silicon boron carbon, iron silicon boron and iron silicon boron chromium carbon; And / or, the average particle size of the amorphous alloy powder in step (1) is 10 to 80 μm, and the minimum particle size is 5 to 20 μm; And / or, the mass ratio of the amorphous alloy powder to the insulating resin in step (1) is 100:(1-5); And / or, the insulating resin in step (1) is at least one of silicone resin, phenolic resin and epoxy modified resin.

8. The preparation method according to claim 7, characterized in that: The amorphous alloy powder in step (1) is Fe 78 Si 10 B 10 C2、Fe 76 Si 12 B 12 and Fe 73.7 Si 11 B 11 Cr 2.3 At least one of C2; And / or, the average particle size of the amorphous alloy powder in step (1) is 10 to 60 μm, and the minimum particle size is 2 to 12 μm; And / or, the mass ratio of the amorphous alloy powder to the insulating resin in step (1) is 100:(1-3).

9. The preparation method according to claim 2 or 3, characterized in that: The pressure of the compression molding in step (2) is 1200-2000 MPa; the holding time is 5-10 seconds; And / or, the heat treatment temperature in step (3) is 380-480° C. and the time is 0.5-3 h.

10. The preparation method according to claim 9, characterized in that: The pressure of the compression molding in step (2) is 1200-1700 MPa; the holding time is 5-6 seconds; And / or, the heat treatment temperature in step (3) is 400-450° C. and the time is 0.5-1 h; And / or, the heat treatment in step (3) is performed under a vacuum environment.

11. The preparation method according to claim 2 or 3, characterized in that: The lubricant in step (2) is zinc stearate, and the mass ratio of the lubricant to the coated amorphous alloy composite powder is 0.5 to 1:100; And / or, the mixed coating method in step (1) is: mixing the insulating resin and the amorphous alloy powder modified by discharge plasma, then mixing them evenly with an organic solvent, and drying; And / or, the organic solvent is at least one of acetone and anhydrous ethanol, and the mass ratio of the organic solvent to the mixed powder is 15-25:85-75.

12. Use of the amorphous composite magnetic powder core of oxide + α-Fe double cluster insulating shell according to claim 1 in the preparation of inductor components.

13. The application according to claim 12, characterized in that: The application areas of the inductive components are 5G communications, solar charging panels, 5G base stations, new energy vehicles, car charging piles, home appliances, airborne power systems, industrial inverters, satellite communications, switching power supplies and photovoltaic inverters.

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