Aluminum nickel iron magnetic powder core and its preparation method and application

Abstract

The present application relates to the field of magnetic material technology, and more specifically, to an aluminum-nickel-iron magnetic powder core and its preparation method and application. An aluminum-nickel-iron magnetic powder core comprises the following components in parts by weight: 30-85 parts of modified aluminum-nickel-iron magnetic powder, 11-55 parts of resin composition, 2-10 parts of diluent, 0.3-1.2 parts of curing agent and 0.5-2.5 parts of accelerator, wherein the resin composition comprises polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin. An aluminum-nickel-iron magnetic powder core of the present application improves the problems of insufficient magnetic properties, high eddy current loss, poor high-frequency performance of existing magnetic powder cores, and difficulty in meeting some market demands, so that the obtained aluminum-nickel-iron magnetic powder core has high effective magnetic permeability, large magnetic flux density, and low eddy current loss, meeting the market demand for magnetic powder core performance.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic materials, and more specifically, to an Al-Nickel-Fe magnetic powder core and a preparation method and application thereof. Background Art

[0002] Metal powder core is a magnetic component made by mixing and pressing ferromagnetic particles and insulating coating agents. The magnetic powders are separated by non-magnetic insulating media and the particles are insulated from each other. Therefore, the eddy current loss of the powder core is very small at medium and high frequencies. Its magnetic permeability is small but has good linearity. It has a high saturation magnetic induction intensity and can be used in high-frequency occasions. With the rapid development of information technology and electromechanical industries, magnetic devices are required to develop in the direction of high frequency, miniaturization and intelligence. This requires the metal powder core as the core of magnetic devices to have high saturation magnetic induction intensity, excellent DC bias capability and low high-frequency loss.

[0003] The magnetic powder cores currently produced and used in the market have their own characteristics and application fields. Among them, it is difficult for magnetic powder cores to have the characteristics of saturation flux density, low loss, and excellent comprehensive magnetic properties at the same time, and the expensive manufacturing cost limits its production and application. With the rapid development of modern electronic technology, higher requirements are put forward for the application of magnetic devices under high power, which urgently requires relevant personnel to develop a low-cost, high-performance magnetic powder core to replace the high-flux magnetic powder core. Low-cost materials with high saturation magnetic induction intensity, low loss ratio, and DC bias characteristics have become a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0004] In view of the problems that existing magnetic powder cores have insufficient magnetic properties, high eddy current losses, poor high-frequency performance, and are difficult to meet some market demands, the present application provides an aluminum-nickel-iron magnetic powder core and a preparation method and application thereof.

[0005] In the first aspect, the present application provides an Al-Nickel-Fe magnetic powder core, which adopts the following technical solution:

[0006] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 30-85 parts of modified aluminum nickel iron magnetic powder, 11-55 parts of a resin composition, 2-10 parts of a diluent, 0.3-1.2 parts of a curing agent and 0.5-2.5 parts of an accelerator, wherein the resin composition comprises a polyetherimide modified epoxy resin, a phenolic resin and a hyperbranched polyimide resin.

[0007] By adopting the above technical scheme, on the one hand, the viscosity of the magnetic powder is reduced by modifying the aluminum-nickel-iron magnetic powder so that the magnetic powder has better fluidity, which is convenient for better casting and curing of the aluminum-nickel-iron magnetic powder core, and the saturation magnetic flux density of the material is increased, thereby improving the magnetic permeability. On the other hand, the modified nickel-nickel-iron magnetic powder and the resin composition are used together to isolate the metal powders from each other through the resin composition to avoid the high loss caused by the connection of the metal powders, and the magnetic permeability decreases rapidly with the increase of frequency. If the amount of the resin composition is too small, it is difficult to achieve a sufficient insulation effect, and thus the loss is difficult to reduce; if the amount of the resin composition is too large, the magnetic permeability of the magnetic powder core is reduced, and then the inductance value is reduced. The resin composition combined with the diluent can effectively improve the grain boundary bonding force and density of the magnetic powder core material, further improve the magnetic properties of the aluminum-nickel-iron magnetic powder material, and improve the insulation of the material, and can form an excellent coating on the surface of the aluminum-nickel-iron magnetic powder, and the structure of the coating layer is stable, further improving the inductance and saturation characteristics of the aluminum-nickel-iron magnetic powder core material.

[0008] Preferably, the modified aluminum nickel iron magnetic powder is 80-85 parts, the resin composition is 11-21 parts, the diluent is 2-5 parts, the curing agent is 0.3-1.0 parts and the accelerator is 0.5-2 parts, and the resin composition includes polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin.

[0009] By adopting the above technical scheme, the resin composition process is used for coating to improve the insulation performance, increase the resistivity and reduce the loss. The modified epoxy resin is matched with the phenolic resin, so that the epoxy resin has good adhesiveness and can improve its heat resistance. Combined with the highly branched molecular chain distribution of the hyperbranched polyimide resin, it has a surface terminal functional group with a high distribution density, and the hyperbranched polyimide resin also has excellent rheological properties, which can interact with the modified aluminum nickel iron body magnetic powder to further improve the dispersion performance of the magnetic powder. In addition, the surface terminal functional groups of the hyperbranched polyimide resin can also be cross-linked with the epoxy group, so that it is closely combined with the base metal and can continue to be used as an insulating coating layer. The coated magnetic powder core has better high-frequency magnetic permeability and high insulation performance, as well as good high temperature resistance, bonding performance and high resistivity. Therefore, through the interaction between the resin composition and the modified magnetic powder, the magnetic powder core can be crack-free and has excellent performance; in practical applications, the device can be used at a very wide and higher frequency.

[0010] In a specific embodiment, the mass ratio of the polyetherimide-modified epoxy resin, the phenolic resin and the hyperbranched polyimide resin is (5-8):(1-3):1.

[0011] In a specific embodiment, the preparation method of the polyetherimine-modified epoxy resin is to blend polyetherimine with an epoxy resin having an epoxy value of 0.7-0.72 in diaminodiphenyl sulfone to obtain a polyetherimine-modified epoxy resin material.

[0012] In a specific embodiment, the mass ratio of the polyetherimide to the epoxy resin is 1:(2-4).

[0013] By adopting the above technical scheme, the polyetherimide modified epoxy resin can further improve the temperature resistance and adhesiveness, enhance the degree of cross-linking with the hyperbranched polyimide resin, enhance the casting tightness of the magnetic powder core material, improve the magnetic permeability of the material, and thus reduce high-frequency loss.

[0014] In a specific embodiment, the modified Alnico magnetic powder is Alnico magnetic powder treated with a silane coupling agent; the mass ratio of the silane coupling agent to the Alnico magnetic powder is 1:(20-25).

[0015] In a specific embodiment, the Alnico magnetic powder includes 85-91 parts of iron, 5-8.5 parts of aluminum, and 3.0-4.2 parts of nickel.

[0016] On the basis of reasonable proportion of Al-Ni-Fe components, the soft magnetic properties of soft magnetic powder core can be significantly improved, and its effective magnetic permeability and saturation magnetic flux density can be increased. Adding an appropriate amount of nickel element can reduce the coercive force of the material to a certain extent, resulting in the material having a good magnetization response ability, making the magnetic permeability higher, and helping to obtain high-density magnetic powder to further improve the magnetic permeability. Al-Ni-Fe magnetic powder can increase the resistivity of soft magnetic powder core, and reducing eddy current loss can significantly reduce high-frequency loss.

[0017] In a second aspect, the present application provides a method for preparing an aluminum-nickel-iron magnetic powder core, using the following technical solution:

[0018] A method for preparing an Alnico magnetic powder core comprises the following steps: dispersing and dissolving a resin composition in an acetone solution, then uniformly adding a modified Alnico magnetic powder, stirring the mixture at 30-60°C until the acetone is completely volatilized, and performing insulation bonding and coating; after the insulation coating is completed, adding an accelerator and a curing agent, mixing the mixture uniformly, placing the sample in a nitrogen or argon protective atmosphere at a pressure of 0.5-2.0 MPa, casting and curing to form the sample, and cooling the sample with the furnace to obtain an Alnico magnetic powder core.

[0019] The Al-Nickel-Fe magnetic powder core is better cast and solidified to avoid the problem of die-casting, which would damage the insulating layer of the soft magnetic material.

[0020] In a specific embodiment, the curing temperature is 120-200° C. and the temperature is kept constant for 3-5 hours.

[0021] Alnico magnetic powder cores are used in the inductor manufacturing process.

[0022] In summary, this application has the following beneficial effects:

[0023] 1. Modified aluminum-nickel-iron magnetic powder reduces the viscosity of magnetic powder so that the magnetic powder has better fluidity, which is convenient for better casting and curing of aluminum-nickel-iron magnetic powder core, and improves the saturation magnetic flux density of the material and thus the magnetic permeability. The modified nickel-nickel-iron magnetic powder and the resin composition work together to isolate the metal powders from each other through the resin composition, avoiding the high loss caused by the connection between the metal powders and the rapid decrease in magnetic permeability with the increase of frequency. If the amount of the resin composition is too small, it is difficult to achieve a sufficient insulation effect, and thus the loss is difficult to reduce; if the amount of the resin composition is too large, the magnetic permeability of the magnetic powder core is reduced, resulting in a decrease in the inductance value. The resin composition combined with the diluent can effectively improve the grain boundary bonding force and density of the magnetic powder core material, further improve the magnetic properties of the aluminum-nickel-iron magnetic powder material, and improve the insulation of the material, and can form an excellent coating effect on the surface of the aluminum-nickel-iron magnetic powder, and the structure of the coating layer is stable, further improving the inductance and saturation characteristics of the aluminum-nickel-iron magnetic powder core material.

[0024] 2. Use resin composition technology to coat to improve insulation performance, increase resistivity and reduce loss. The modified epoxy resin is matched with phenolic resin, so that the epoxy resin has good adhesiveness and can improve its heat resistance. Combined with the highly branched molecular chain distribution of the hyperbranched polyimide resin, it has a high distribution density of surface terminal functional groups, and the hyperbranched polyimide resin also has excellent rheological properties, which can interact with the modified aluminum nickel iron body magnetic powder to further improve the dispersion performance of the magnetic powder. In addition, the surface terminal functional groups of the hyperbranched polyimide resin can also be cross-linked with the epoxy group, so that it is closely bonded to the base metal and can continue to be used as an insulating coating layer. The coated magnetic powder core has better high-frequency magnetic permeability and high insulation performance, as well as good high temperature resistance, bonding performance and high resistivity. Therefore, through the interaction between the resin composition and the modified magnetic powder, the magnetic powder core can be crack-free and has excellent performance; in practical applications, the device can be used at a very wide and higher frequency. DETAILED DESCRIPTION

[0025] The present application is further described in detail below in conjunction with embodiments.

[0026] Some raw materials used in the preparation examples and embodiments: hyperbranched polyimide resin product number: 114615; polyetherimide product number: HH8220MQX29X; epoxy resin brand: sc-1; the diluent is acetone; silane coupling agent model: KH-550; curing agent model: T-31; accelerator is K54 epoxy accelerator, product number: 230324; diaminodiphenyl sulfone is 4,4-diaminophenyl sulfone purchased from Wuhan Shuer Biotechnology Co., Ltd.

[0027] The raw materials used in the examples and comparative examples that are not otherwise specified are all conventional products that can be purchased from the market.

[0028] Preparation of polyetherimide modified epoxy resin

[0029] Preparation Example 1

[0030] Take 10g of polyetherimine and 20g of epoxy resin in 100g of diaminodiphenyl sulfone, mix them with mechanical stirring under 100℃ oil bath heating for 10h, and cool to room temperature to obtain polyetherimine modified epoxy resin material.

[0031] Preparation Example 2

[0032] Take 10g of polyetherimine and 40g of epoxy resin in 100g of diaminodiphenyl sulfone, mix them with mechanical stirring under 100℃ oil bath heating for 10h, and cool to room temperature to obtain polyetherimine modified epoxy resin material.

[0033] Preparation Example 3

[0034] Take 10g of polyetherimine and 50g of epoxy resin in 100g of diaminodiphenyl sulfone, mix them with mechanical stirring under 100℃ oil bath heating for 10h, and cool to room temperature to obtain polyetherimine modified epoxy resin material.

[0035] Preparation of modified Al-Ni-Fe magnetic powder

[0036] Preparation Example 4

[0037] 200 g of Al-Ni-Fe magnetic powder was added into a powder processor and stirred at a speed of 200 rpm. Subsequently, 10 g of coupling agent KH-550 was added into a spray container and sprayed at a spray pressure of 0.6 MPa. The powder was stirred for 50 min to obtain modified Al-Ni-Fe magnetic powder.

[0038] Preparation Example 5

[0039] 250 g of Al-Ni-Fe magnetic powder was added into a powder processor and stirred at a speed of 200 rpm. Subsequently, 10 g of coupling agent KH-550 was added into a spray container and sprayed at a spray pressure of 0.6 MPa. The powder was stirred for 50 min to obtain modified Al-Ni-Fe magnetic powder. Example Example 1

[0040] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 300 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 550 g of a resin composition, 20 g of a diluent, 12 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 91:8.5:3, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0041] The resin composition was dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum-nickel-iron magnetic powder was mixed and added evenly, and fully stirred at 30°C until the acetone was completely volatilized, and then the insulation bonding coating was performed; after the insulation coating was completed, the accelerator and the curing agent were added and mixed evenly. Under a pressure of 2.0 MPa, the sample was placed in a nitrogen protective atmosphere at a temperature of 120°C for 5 hours. After pouring and curing, it was cooled with the furnace to obtain an aluminum-nickel-iron magnetic powder core. Example 2

[0042] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 300 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 110 g of a resin composition, 80 g of a diluent, 3 g of a curing agent and 25 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0043] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 3

[0044] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 800 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 110 g of a resin composition, 50 g of a diluent, 10 g of a curing agent and 20 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0045] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 4

[0046] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0047] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 5

[0048] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 8:1:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0049] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 6

[0050] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:4:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0051] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 7

[0052] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 2.

[0053] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 8

[0054] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 3.

[0055] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core. Example 9

[0056] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 5, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin is 5:3:1, and the polyetherimide modified epoxy resin is obtained in Preparation Example 1.

[0057] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core.

[0058] Comparative Example 1

[0059] An alnico-ferrite magnetic powder core comprises the following components in parts by mass: 850 g of alnico-ferrite magnetic powder, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent and 5 g of an accelerator, wherein the mass ratio of iron, aluminum and nickel in the alnico-ferrite magnetic powder is 85:5:4.2, the resin composition is polyetherimide-modified epoxy resin, phenolic resin and hyperbranched polyimide resin, the mass ratio of the polyetherimide-modified epoxy resin, the phenolic resin and the hyperbranched polyimide resin is 5:3:1, and the polyetherimide-modified epoxy resin is prepared in Preparation Example 1.

[0060] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the aluminum nickel iron magnetic powder is mixed and evenly added, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core.

[0061] Comparative Example 2

[0062] A aluminum nickel iron magnetic powder core comprises the following components in parts by mass: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent, and 5 g of an accelerator, wherein the mass ratio of iron, aluminum, and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, and the resin is a polyetherimide-modified epoxy resin obtained in Preparation Example 1.

[0063] The resin is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum-nickel-iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum-nickel-iron magnetic powder core.

[0064] Comparative Example 3

[0065] An aluminum nickel iron magnetic powder core comprises the following components in parts by mass: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent, and 5 g of an accelerator, wherein the mass ratio of iron, aluminum, and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, and the resin is a phenolic resin.

[0066] The resin is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum-nickel-iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum-nickel-iron magnetic powder core.

[0067] Comparative Example 4

[0068] An aluminum nickel iron magnetic powder core comprises the following components in parts by mass: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent, and 5 g of an accelerator, wherein the mass ratio of iron, aluminum, and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, and the resin is a hyperbranched polyimide resin.

[0069] The resin is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum-nickel-iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen or argon protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum-nickel-iron magnetic powder core.

[0070] Comparative Example 5

[0071] An aluminum nickel iron magnetic powder core comprises the following components in parts by mass: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent, and 5 g of an accelerator, wherein the mass ratio of iron, aluminum, and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is polyetherimide-modified epoxy resin and phenolic resin, the mass ratio of polyetherimide-modified epoxy resin and phenolic resin is 8:1, and the polyetherimide-modified epoxy resin is obtained in Preparation Example 1.

[0072] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core.

[0073] Comparative Example 6

[0074] An aluminum nickel iron magnetic powder core comprises the following components in parts by weight: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent, and 5 g of an accelerator, wherein the mass ratio of iron, aluminum, and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is a polyetherimide-modified epoxy resin and a hyperbranched polyimide resin, the mass ratio of the polyetherimide-modified epoxy resin to the hyperbranched polyimide resin is 8:1, and the polyetherimide-modified epoxy resin is obtained in Preparation Example 1.

[0075] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core.

[0076] Comparative Example 7

[0077] An aluminum nickel iron magnetic powder core comprises the following components in parts by mass: 850 g of modified aluminum nickel iron magnetic powder obtained in Preparation Example 4, 210 g of a resin composition, 20 g of a diluent, 3 g of a curing agent, and 5 g of an accelerator, wherein the mass ratio of iron, aluminum, and nickel in the aluminum nickel iron magnetic powder is 85:5:4.2, the resin composition is a phenolic resin and a hyperbranched polyimide resin, and the mass ratio of the phenolic resin to the hyperbranched polyimide resin is 8:1.

[0078] The resin composition is dispersed and dissolved in 300 ml of acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added evenly, and fully stirred at 60°C until the acetone is completely volatilized, and then the insulation bonding coating is performed; after the insulation coating is completed, the accelerator and the curing agent are added and mixed evenly. Under a pressure of 0.5 MPa, the sample is placed in a nitrogen protective atmosphere at a temperature of 200°C and kept at a constant temperature for 3 hours. After pouring and curing, it is cooled with the furnace to obtain an aluminum nickel iron magnetic powder core.

[0079] The performance test of an Al-Ni-Fe magnetic powder core prepared in the embodiment and the comparative example is carried out by the following method:

[0080] The test process is: 100kHz effective magnetic permeability μe: A precision magnetic analyzer is used to measure the effective magnetic permeability μe at a frequency of 100kHz, and the test voltage is fixed at 1V.

[0081] Static saturation magnetic flux density Bs: The BH soft magnetic DC measurement system is used to test the magnetic flux density Bs under a set saturation magnetic field of 30500A / m.

[0082] Loss Pc at 50kHz / 50mT: The volume loss Pc at a frequency of 50kHz and a magnetic flux density of 50mT is measured using an AC loss test system; the comparison results are shown in Table 1 below:

[0083] Table 1 Performance test results

[0084]

[0085] It can be seen from Table 1 that the Alnico magnetic powder core obtained in the above embodiment has high effective magnetic permeability, high magnetic flux density, and low eddy current loss, thus meeting the market demand for magnetic powder core performance.

[0086] Compared with Comparative Example 1 and Example 4, it can be seen that the effective magnetic permeability, magnetic flux density, and eddy current loss indicators of the aluminum nickel iron magnetic powder core prepared in Example 4 are better than those of Comparative Example 1. Analysis shows that by modifying the aluminum nickel iron magnetic powder to reduce the viscosity of the magnetic powder, the magnetic powder has better fluidity, which is convenient for better casting and curing of the aluminum nickel iron magnetic powder core, and the saturation magnetic flux density of the material is increased, thereby increasing the magnetic permeability and reducing the eddy current loss.

[0087] By comparing Example 4 with Comparative Examples 2-7, it can be seen that the effective magnetic permeability, magnetic flux density and eddy current loss indicators of the aluminum-nickel-iron magnetic powder core prepared in Example 4 are better than those of Comparative Examples 2-7. Analysis shows that the resin composition process is used for coating to improve insulation performance, increase resistivity and reduce loss. The modified epoxy resin is matched with the phenolic resin, so that the epoxy resin has good adhesiveness and can improve its heat resistance. Combined with the highly branched molecular chain distribution of the hyperbranched polyimide resin, it has a surface terminal functional group with a high distribution density, and the hyperbranched polyimide resin also has excellent rheological properties. The surface terminal functional groups of the hyperbranched polyimide resin can also be cross-linked with the epoxy group, so that it is tightly bonded to the base metal and can continue to be used as an insulating coating. The coated magnetic powder core has better high-frequency magnetic permeability and high insulation performance, as well as good high temperature resistance, bonding performance and high resistivity. Therefore, through the interaction between the resin composition and the modified magnetic powder, the magnetic powder core can be free of cracks and has excellent performance; in practical applications, the device can be used at a very wide and higher frequency.

[0088] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An Al-Nickel-Fe magnetic powder core, characterized in that: The invention comprises the following components in parts by weight: 30-85 parts of modified aluminum nickel iron magnetic powder, 11-55 parts of resin composition, 2-10 parts of diluent, 0.3-1.2 parts of curing agent and 0.5-2.5 parts of accelerator, wherein the resin composition is polyetherimide modified epoxy resin, phenolic resin and hyperbranched polyimide resin; The mass ratio of the polyetherimide modified epoxy resin, the phenolic resin and the hyperbranched polyimide resin is (5-8): (1-3): 1; The preparation method of the polyetherimine modified epoxy resin is as follows: polyetherimine and an epoxy resin with an epoxy value of 0.7-0.72 are mixed in diaminodiphenyl sulfone to obtain the polyetherimine modified epoxy resin; The mass ratio of the polyetherimide to the epoxy resin is 1:(2-4); The aluminum nickel iron magnetic powder includes 85-91 parts of iron, 5-8.5 parts of aluminum, and 3.0-4.2 parts of nickel.

2. The Al-Nickel-Fe magnetic powder core according to claim 1, characterized in that: The modified Al-Ni-Fe magnetic powder is Al-Ni-Fe magnetic powder treated with a silane coupling agent; the mass ratio of the silane coupling agent to the Al-Ni-Fe magnetic powder is 1:(20-25).

3. The method for preparing the Al-Ni-Fe magnetic powder core according to any one of claims 1 to 2, characterized in that: The steps include: The resin composition is dispersed and dissolved in an acetone solution, and then the modified aluminum nickel iron magnetic powder is mixed and added uniformly, and fully stirred at 30-60° C. until the acetone is completely volatilized, and then the insulation bonding coating is performed; After the insulation coating is completed, add the accelerator and curing agent, mix them evenly, place the sample in a nitrogen or argon protective atmosphere at a pressure of 0.5-2.0MPa, pour and solidify the sample, and cool it in the furnace to obtain an aluminum nickel iron magnetic powder core.

4. The method for preparing an Al-Ni-Fe magnetic powder core according to claim 3, characterized in that: The curing molding temperature is 120-200° C. and the temperature is kept constant for 3-5 hours.

5. Use of the Al-Ni-Fe magnetic powder core according to any one of claims 1 to 2 in an inductor preparation process.

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