Magnetic composite glue, preparation method and application thereof

Abstract

The application discloses a kind of magnetic composite glue, preparation method and application, belong to magnetic material field, the structural characteristics of magnetic composite glue is multiscale hetero-interface, it includes the following components according to weight percentage: 15-30% epoxy resin matrix, paint or silica gel, 10-99% graphene, 30-60% magnetic powder, 5-20% iron-silicon alloy powder and 0.5-1.0% silane coupling agent;Key interface reaction in composite glue generates chemical bridging structure.The above-mentioned magnetic composite glue, preparation method and application are used, through chemical bonding interface, multiscale material design and process precision control trinity innovation, break through the contradiction of high-frequency magnetic material "high loss-low strength-weak heat dissipation", provide bottom material support for high reliability electronic system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic materials, in particular to a magnetic composite adhesive, a preparation method and application. BACKGROUND

[0002] At present, in the field of manufacturing magnetic components, the conventional magnetic conductive adhesive is mainly composed of epoxy adhesive as the base material, combined with curing agent, toughening agent and carbonyl iron powder, etc. Or polyphenyl ethylene, polyethylene and other high molecular materials are blended with ferrite powder and carbonyl iron powder to prepare. Such materials mainly undertake the dual functions of magnetic medium bonding and particle insulation; on the one hand, the shaping process of ferrite powder is realized through the bonding effect, and on the other hand, the eddy current loss in the alternating magnetic field is reduced by isolating iron powder particles, so as to improve the quality factor of the magnetic core.

[0003] However, through practice verification, the existing magnetic conductive adhesive technology has the following significant defects:

[0004] 1. Poor adaptability to high frequency working conditions: when the working frequency exceeds 5MHz, the dielectric loss of the material increases sharply, resulting in a significant decrease in current carrying capacity;

[0005] 2. Insufficient thermal stability: the glass transition temperature interval is narrow (80-100℃), and the mismatch rate of the thermal expansion coefficient with the magnetic base material is >15%, which causes high temperature interface peeling;

[0006] 3. Lack of heat dissipation performance: the thermal conductivity coefficient is generally lower than 0.3W / (m·K), which cannot effectively conduct the Joule heat generated under high frequency working conditions;

[0007] 4. Low comprehensive electromagnetic performance: the relative magnetic permeability , the loss tangent , which is difficult to meet the energy efficiency requirements of high frequency transformers;

[0008] 5. Insufficient electromagnetic shielding performance: the shielding performance is <20dB in the frequency band of 1-10GHz, which causes the transformer spray coating and shell to fail to achieve effective electromagnetic radiation suppression.

[0009] The above technical defects seriously restrict the development of high frequency magnetic devices towards miniaturization and high power density. SUMMARY

[0010] The purpose of the present application is to provide a magnetic composite adhesive, a preparation method and application, which solves the above technical problems.

[0011] To achieve the above object, the application provides a magnetic composite glue, which has a structure of multi-scale heterogeneous interface and comprises the following components in percentage by weight: 15-30% of an epoxy resin matrix, paint or silica gel, 10-99% of graphene, 30-60% of magnetic powder, 5-20% of iron-silicon alloy powder and 0.5-1.0% of silane coupling agent.

[0012] The key interface reaction in the composite glue generates a chemical bridging structure, and the bonding of the silane coupling agent and the magnetic powder is Fe / Si / Al particle surface ≡Si-O-Fe / Si / Al, wherein the bond type is a covalent bond and the bond energy is 103.5 eV.

[0013] Preferably, the purity of the graphene is greater than 99.9% and the number of layers is less than 6; and the mesh number of the iron-silicon alloy powder is 50-300.

[0014] A preparation method of the magnetic composite glue comprises the following steps:

[0015] S1, preparing the epoxy resin matrix, paint or silica gel, graphene, magnetic powder, iron-silicon alloy powder and silane coupling agent according to the weight components;

[0016] S2, ultrasonic mixing: the iron-silicon alloy powder and the magnetic powder are loaded into a sealed constant-temperature ultrasonic tank for ultrasonic dispersion treatment to obtain a composite material;

[0017] S3, ball milling treatment: the silane coupling agent and steel balls are added to the composite material for ball milling treatment to obtain a powder composite material;

[0018] S4, shear emulsification: the paint, epoxy resin or silica gel is added to the powder composite material for shear emulsification treatment to obtain the magnetic composite glue.

[0019] Preferably, in step S2, the ultrasonic mixing time is 4 h and the temperature is 100°C.

[0020] Preferably, in step S3, the ball milling treatment time is 4 h, the temperature is 100°C and the PH value is 6;

[0021] In step S3, the silane coupling agent undergoes the following hydrolysis and condensation reaction:

[0022]

[0023] .

[0024] Preferably, in step S4, the shear emulsification time is 6 h;

[0025] When the epoxy resin is added, the amino group in the powder composite material undergoes the following coupling reaction:

[0026] .

[0027] Application of the magnetic composite adhesive on inductance coating, transformer external spraying, metallization of electrodes on ferrite cores, coils, bypass shielding, thermal radiation conduction, magnetic core packaging, electromagnetic shielding and filters.

[0028] Therefore, the application of the above-mentioned magnetic composite adhesive, preparation method and application has the beneficial effects of:

[0029] 1. Improving the magnetic flux by more than 15%: by introducing graphene, iron-silicon alloy powder and magnetic powder, the magnetic permeability is significantly improved; specifically, graphene has excellent electrical conductivity and thermal conductivity, which can effectively reduce the internal resistance of the material and reduce hysteresis loss, at the same time, the addition of iron-silicon alloy powder and magnetic powder further enhances the magnetic induction intensity of the material, so that the magnetic flux is increased by more than 15% under the same conditions; this not only improves the overall magnetic performance of the material, but also provides more efficient energy transmission for high-frequency inductors and transformers and other applications;

[0030] 2. Excellent broadband electromagnetic wave shielding effectiveness: by optimizing the types and distribution of fillers, effective shielding of broadband electromagnetic waves is achieved; the principle lies in that graphene and magnetic powder can absorb and dissipate electromagnetic energy in different frequency ranges, thereby preventing electromagnetic waves from penetrating the surface of the material; in addition, ultrasonic dispersion and ball milling process ensures uniform distribution of fillers, forming a multi-layer electromagnetic shielding barrier that effectively covers a wide frequency range from low to high frequencies; this broadband electromagnetic wave shielding characteristic is crucial for anti-interference design in electronic devices, especially in the fields of wireless communication, radar and microwave technology;

[0031] 3. Reducing eddy current loss and improving efficiency under high-frequency application: by introducing graphene with high electrical conductivity and magnetic powder with high magnetic permeability, the generation of eddy current is effectively suppressed; specifically, the two-dimensional structure of graphene can disperse current paths and reduce concentration effects, while magnetic powder improves the coupling efficiency of the magnetic circuit and reduces the wasteful consumption of magnetic field energy; therefore, under high-frequency current, the eddy current loss of the material is greatly reduced, significantly improving the overall working efficiency and reducing energy loss and heat accumulation;

[0032] 4. Application in high-frequency low-loss scenarios with low coercivity, high magnetic permeability and low hysteresis loss: first, low coercivity means that the material requires less energy for reverse magnetization when the magnetic field changes, which helps to quickly respond to changes in high-frequency signals; second, high magnetic permeability enables the material to achieve efficient magnetic flux transmission at lower magnetic field strengths, further improving energy utilization efficiency; third, low hysteresis loss reduces energy loss during repeated magnetization of the magnetic field, prolonging the service life of the device, especially suitable for high-frequency inductors and transformers that need to operate stably for a long time;

[0033] 5. Prolonged service life of the device: by improving the magnetic permeability of the material and reducing the hysteresis loss, the thermal stability and mechanical strength of the device are significantly improved; specifically, the heat conduction path inside the material is optimized, heat can be quickly dissipated, and local overheating phenomenon is avoided, at the same time, the high-strength composite structure can withstand greater stress and vibration, ensuring the long-term reliability of the device in complex environments; in addition, the oxidation resistance and corrosion resistance of the material are also enhanced, further prolonging the service life of the device and reducing the maintenance cost;

[0034] 6. Lightweight, high strength and electromagnetic shielding: lightweight and high-strength graphene and magnetic powder are used as fillers, which not only reduces the weight of the material, but also maintains good mechanical properties; the two-dimensional structure of graphene endows the material with excellent mechanical strength and flexibility, enabling it to have sufficient support force even in a thin case; at the same time, the presence of magnetic powder enhances the electromagnetic shielding effect of the material, forming a new type of composite material with lightweight, high strength and electromagnetic shielding characteristics, which is particularly suitable for aerospace, automotive electronics and portable electronic devices, etc. fields, which can not only reduce weight, but also provide reliable electromagnetic protection.

[0035] The technical solutions of the present application will be further described in detail below with the help of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The flowchart of the preparation method of the magnetic composite glue described in the present application;

[0037] Figure 2 The ripple processing test comparison chart of the test example of the present application, wherein (a) is the ripple test chart using ordinary coating material; (b) is the ripple test chart using magnetic composite glue;

[0038] Figure 3 The EMI (electromagnetic interference) test chart of the test example of the present application. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the embodiments of the present application will be further described in detail below with the help of the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present application and not to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. The examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout.

[0040] It is to be understood that the terms "including", "comprising", "having" and their conjugates mean "including but not limited to", e.g. a process, method, object, or apparatus that includes a list of steps or elements is not necessarily limited to those specifically listed and can include other steps or elements not expressly listed or inherent to such process, method, object, or apparatus.

[0041] Embodiments of the present application will be described in detail below with reference to the drawings.

[0042] A magnetic composite glue, the structural characteristics of the magnetic composite glue are multi-scale heterogeneous interfaces, and the magnetic composite glue comprises the following components in percentage by weight: 15%-30% of an epoxy resin matrix, paint or silica gel, 10%-99% of graphene, 30%-60% of magnetic powder, 5%-20% of iron-silicon alloy powder and 0.5%-1.0% of a silane coupling agent; a chemical bridging structure is generated in a key interface reaction in the composite glue, and the bonding of the silane coupling agent and the magnetic powder is Fe / Si / Al particle surface ≡Si-O-Fe / Si / Al, wherein the bond type is a covalent bond, and the bond energy is 103.5 eV; that is, the Fe3Si / FeSiAl magnetic powder, the graphene and the epoxy resin matrix are modified by the silane coupling agent, and inorganic-organic interface bridging is achieved through the Si-O-M covalent bond (M=Fe / Si / Al). The graphene serves as a reinforcing agent of the composite material, and provides excellent electrical conductivity and thermal conductivity; the iron-silicon alloy powder has high magnetic permeability and low coercivity, and is combined with the good electrical conductivity of the graphene to further improve the electromagnetic performance of the composite material; and the magnetic powder is used to improve the magnetic properties of the material.

[0043] Preferably, the purity of the graphene is greater than 99.9%, and the number of layers of the graphene is less than 6; and the mesh number of the iron-silicon alloy powder is 50-300.

[0044] As shown in Figure 1 A preparation method of a magnetic composite glue, comprising the following steps:

[0045] S1, preparing an epoxy resin matrix, paint or silica gel, graphene, magnetic powder, iron-silicon alloy powder and a silane coupling agent according to weight components;

[0046] S2, ultrasonic mixing: the iron-silicon alloy powder and the magnetic powder are loaded into a sealed constant-temperature ultrasonic tank, and ultrasonic dispersion treatment is performed to obtain a composite material;

[0047] S3, ball milling treatment: the silane coupling agent and steel balls are added to the composite material, and ball milling treatment is performed to obtain a powder composite material;

[0048] S4, shear emulsification: the paint, the epoxy resin or the silica gel is added to the powder composite material, and shear emulsification treatment is performed to obtain the magnetic composite glue.

[0049] Preferably, in step S2, the ultrasonic mixing time is 4h and the temperature is 100℃.

[0050] Preferably, in step S3, the ball milling time is 4h, the temperature is 100℃, and the pH value is 6;

[0051] In step S3, the silane coupling agent The hydrolysis and condensation reaction occurs as follows:

[0052]

[0053] .

[0054] In step S4, the shear emulsification time is 6h;

[0055] When the epoxy resin is added, the following coupling reaction occurs with the amino groups in the powder composite material:

[0056] .

[0057] The application of the magnetic composite adhesive on inductors, transformer exteriors, ferrite cores, metalized electrodes, coils, bypass shields, heat radiation and conduction, magnetic core packaging, electromagnetic shielding, and filters.

[0058] Specifically, the magnetic composite adhesive can be directly coated on the surface of the inductor to form a uniform protective film. The following benefits are achieved: (1) Improved magnetic flux: due to the addition of graphene and magnetic powder, the magnetic permeability of the coated inductor is significantly improved, with an increase of about 15% or more in magnetic flux, thereby improving the working efficiency of the inductor. (2) Reduced eddy current loss: the high electrical conductivity of graphene disperses the current path, reducing the eddy current effect and significantly reducing energy loss under high-frequency applications. (3) Enhanced mechanical strength: the coating layer not only provides an improvement in electromagnetic performance, but also enhances the mechanical strength of the inductor, prolonging its service life.

[0059] The magnetic composite adhesive is sprayed on the surface of the transformer shell to form a uniform and dense coating. This coating not only has good adhesion, but also effectively blocks the influence of the external environment on the internal parts of the transformer; it has the following benefits: (1) Wideband electromagnetic wave shielding: the coating can absorb and dissipate electromagnetic waves from low to high frequencies, preventing external electromagnetic interference from entering the internal parts of the transformer and ensuring its stable operation. (2) Improved heat dissipation performance: the coating has good thermal conductivity, which can quickly dissipate the heat generated during the operation of the transformer, preventing overheating and improving overall working efficiency. (3) Protection and corrosion resistance: the oxidation and corrosion resistance of the coating prolongs the service life of the transformer and reduces maintenance costs.

[0060] The magnetic composite glue is used for the metallization treatment of the surface of a ferrite core. The material is uniformly coated on the surface of the core by screen printing or spraying, and then a metal layer is electroplated or chemically plated. It has the following beneficial effects: (1) low coercivity and high permeability: the low coercivity of the material makes the core easy to magnetize and demagnetize, improving the response speed; high permeability ensures efficient magnetic flux transmission, reducing energy loss. (2) Reduce hysteresis loss: the magnetic composite glue effectively reduces the energy consumption of the core during repeated magnetization, improving the efficiency under high frequency application. (3) Enhance the bonding strength: the coating forms a firm bond with the surface of the core, ensuring the long-term stability of the metallized electrode and improving the reliability of the device.

[0061] The magnetic composite glue can be used for winding or filling coils, forming a protective film between or inside and outside the coils, and playing a fixing and supporting role. It has the following beneficial effects: (1) Improve insulation performance: the insulation properties of the material effectively isolate the electrical connection between the coils, preventing short circuit phenomena and improving safety. (2) Enhance magnetic coupling: the magnetic composite glue with high permeability forms good magnetic circuit coupling between the coils, improving the magnetic induction intensity and energy transfer efficiency. (3) Reduce weight and volume: the lightweight and high-strength characteristics of the material make the coil structure more compact, suitable for miniaturization and lightweight design.

[0062] The magnetic composite glue is applied to the key positions of the circuit board or device shell as a bypass shielding material, forming an effective electromagnetic barrier. It has the following beneficial effects: (1) Wideband electromagnetic wave shielding: the material has excellent shielding effectiveness for wideband electromagnetic waves, which can effectively block electromagnetic interference and ensure the normal operation of electronic devices. (2) Strong anti-interference ability: even in complex electromagnetic environments, it can maintain stable shielding effect and avoid signal crosstalk and misoperation. (3) Flexible application: the magnetic composite glue can be customized in thickness and shape according to actual needs, suitable for various complex bypass shielding scenarios.

[0063] The magnetic composite glue is coated on the surface of heat generating elements such as CPU, power tube, etc., to help quickly conduct and dissipate heat. It has the following beneficial effects: (1) High efficiency of heat dissipation: the material has good thermal conductivity, which can quickly conduct heat from the heat source to the heat dissipation device, preventing local overheating and improving the heat dissipation efficiency of the device. (2) Prolong the service life: by effectively controlling the temperature, it reduces the damage of the heat generating element caused by overheating, prolonging its service life. (3) Optimize thermal management: the magnetic composite glue can adjust the coating thickness according to different heating conditions, achieving precise thermal management, suitable for high-performance computing and industrial control fields.

[0064] The magnetic composite glue is used for packaging the magnetic core, which is wrapped outside the magnetic core to form a complete protective shell. It has the following beneficial effects: (1) Enhance mechanical strength: The packaging layer not only protects the magnetic core from physical damage, but also enhances the stability of its overall structure, improving the impact and vibration resistance. (2) Moisture and corrosion resistance: The moisture and corrosion resistance of the material ensures that the magnetic core can maintain good performance in humid or corrosive environments. (3) Simplify the assembly process: The solid shell formed after the magnetic composite glue solidifies facilitates the assembly of the magnetic core and other components, simplifying the production process and improving production efficiency.

[0065] The magnetic composite glue is coated or sprayed on the outer shell or internal key components of electronic equipment to form an effective electromagnetic shielding layer. It has the following beneficial effects: (1) Wide frequency electromagnetic wave shielding: The material has excellent shielding effect on electromagnetic waves from low frequency to high frequency, ensuring that the internal circuit of the device is not affected by external electromagnetic interference. (2) Strong anti-interference ability: In a complex electromagnetic environment, the magnetic composite glue can maintain stable shielding performance, avoiding signal interference and misoperation. (3) Lightweight and flexibility: The lightweight characteristics of the material make it suitable for electromagnetic shielding needs of various shapes and sizes, ensuring shielding effect without increasing device weight.

[0066] The magnetic composite glue is used for key components of filters such as magnetic rings and magnetic rods, which are evenly coated on their surfaces through dipping, spraying or injection molding. It has the following beneficial effects: (1) Improve filter performance: The high magnetic permeability and low magnetic hysteresis loss characteristics of the material improve the selectivity and attenuation effect of the filter on specific frequency signals, enhancing the filter performance. (2) Reduce energy loss: Low coercivity and low magnetic hysteresis loss reduce the energy loss of the filter during operation, improving overall efficiency. (3) Enhance reliability: The application of magnetic composite glue improves the mechanical strength and anti-aging performance of the filter, ensuring its stable and reliable performance in long-term use.

[0067] Test example

[0068] In this test example, the verification of the magnetic composite glue on the improvement of circuit stability, filtering and ripple reduction is carried out.

[0069] The magnetic composite glue and ordinary coating material described in the present application are respectively coated on a 40nH inductor, and the filter unit is connected in series in an AC-DC circuit. The filtering effect at different times is recorded, and the results are as follows: Figure 2As shown, it can be seen that the filter unit coated with the magnetic composite glue has obvious improvement in ripple processing. From the data, the average of the ripple is significantly reduced, such as from 27.0 mV to 35.9 μV; from the graphical features, the width of the energy concentration area changes, and the width of the input is wider than that of the output; and the ripple filtering effect and the width of the energy concentration area of the ordinary coated filter unit have no obvious change. This shows that the magnetic composite glue described in the application has a positive effect on the ripple processing of electronic circuits, and can effectively reduce the ripple voltage and optimize the stability of the circuit.

[0070] As shown in Figure 3 After using the magnetic composite glue, the electromagnetic radiation is below the standard limit line, which proves that the magnetic composite glue described in the application can effectively suppress the electromagnetic radiation of electronic equipment.

[0071] Example 1: Low-loss high-frequency application example

[0072] 1. Material preparation: epoxy resin matrix 15%; graphene 99%; magnetic powder 30%; iron-silicon alloy powder 5%; silane coupling agent 1%;

[0073] 2. Ultrasonic mixing: iron-silicon alloy powder and magnetic powder are loaded into a sealed constant-temperature ultrasonic tank, and ultrasonic dispersion treatment is carried out at 100°C for 4 hours to obtain a composite material.

[0074] 3. Ball milling: silane coupling agent and steel balls are added to the composite material, and ball milling treatment is carried out at 100°C and a pH value of 6 for 4 hours to obtain a powder composite material.

[0075] 4. Shear emulsification: epoxy resin matrix is added to the powder composite material, and shear emulsification treatment is carried out in a high-speed emulsifying shear machine for 6 hours to obtain a magnetic composite glue.

[0076] Application field: high-frequency inductor, transformer external spraying or inductor coating.

[0077] Performance characteristics: (1) magnetic flux is increased by about 15% or more; (2) excellent broadband electromagnetic wave shielding efficiency; (3) reduced eddy current loss, improved efficiency under high-frequency application.

[0078] Example 2: Medium-loss medium-frequency application example

[0079] 1. Material preparation: epoxy resin matrix 25%; graphene 50%; magnetic powder 45%; iron-silicon alloy powder 10%; silane coupling agent 0.5%;

[0080] 2. Ultrasonic mixing: iron-silicon alloy powder and magnetic powder are loaded into a sealed constant-temperature ultrasonic tank, and ultrasonic dispersion treatment is carried out at 100°C for 4 hours to obtain a composite material.

[0081] 3. Ball milling: add silane coupling agent and steel balls to the composite material, and ball mill at 100℃ and pH 6 for 4 hours to obtain a powder composite material.

[0082] 4. Shear emulsification: add an epoxy resin matrix to the powder composite material, and perform shear emulsification treatment in a high-speed emulsification shear machine for 6 hours to obtain a magnetic composite glue.

[0083] Application field: filter, electromagnetic shielding material, or coil winding.

[0084] Performance characteristics: (1) balanced permeability and loss, suitable for medium frequency applications; (2) has certain electromagnetic shielding ability; (3) moderate mechanical strength and thermal stability.

[0085] Example 3: high-strength low-frequency application example

[0086] 1. Material preparation: epoxy resin matrix 30%; graphene 10%; magnetic powder 60%

[0087] Iron-silicon alloy powder 20%; silane coupling agent 0.5%;

[0088] 2. Ultrasonic mixing: load the iron-silicon alloy powder and magnetic powder into a sealed constant-temperature ultrasonic tank, and ultrasonic dispersion treatment at 100℃ for 4 hours to obtain a composite material.

[0089] 3. Ball milling: add silane coupling agent and steel balls to the composite material, and ball mill at 100℃ and pH 6 for 4 hours to obtain a powder composite material.

[0090] 4. Shear emulsification: add an epoxy resin matrix to the powder composite material, and perform shear emulsification treatment in a high-speed emulsification shear machine for 6 hours to obtain a magnetic composite glue.

[0091] Application field: low-frequency inductor, magnetic core packaging, or bypass shielding.

[0092] Performance characteristics: (1) high permeability and low coercivity, suitable for low-frequency applications; (2) high strength and high mechanical stability, suitable for occasions that need to withstand large stress; (3) moderate electromagnetic shielding effectiveness, meeting general low-frequency electromagnetic shielding requirements.

[0093] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or equivalently replaced, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A magnetic composite glue, characterized by: The structural feature of the magnetic composite glue is a multi-scale heterogeneous interface, which comprises the following components by weight percentage: 15-30% of epoxy resin matrix, paint or silicone, 10-99% of graphene, 30-60% of magnetic powder, 5-20% of iron-silicon alloy powder and 0.5-1.0% of silane coupling agent; The key interface reaction in the composite glue generates a chemical bridging structure, and the bonding of the silane coupling agent and the magnetic powder is Fe / Si / Al particle surface ≡Si-O-Fe / Si / Al, wherein the bond type is a covalent bond, and the bond energy is 103.5 eV.

2. The magnetic composite glue according to claim 1, characterized in that: The purity of the graphene is greater than 99.9%, and the number of layers is less than 6; the iron-silicon alloy powder has a mesh size of 50-300.

3. A method of preparing a magnetic composite glue according to claim 1 or 2, characterized in that: The method comprises the following steps: S1, preparing epoxy resin matrix, paint or silicone, graphene, magnetic powder, iron-silicon alloy powder and silane coupling agent by weight; S2, ultrasonic mixing: the iron-silicon alloy powder and the magnetic powder are loaded into a sealed constant-temperature ultrasonic tank for ultrasonic dispersion treatment to obtain a composite material; S3, ball milling treatment: the silane coupling agent and steel balls are added to the composite material for ball milling treatment to obtain a powder composite material; S4, shear emulsification: the paint, epoxy resin or silicone is added to the powder composite material for shear emulsification treatment to obtain a magnetic composite glue.

4. The method for preparing a magnetic composite adhesive according to claim 3, characterized in that: In step S2, the ultrasonic mixing time is 4h, and the temperature is 100℃.

5. The method for preparing a magnetic composite adhesive according to claim 3, characterized in that: In step S3, the ball milling treatment time is 4h, the temperature is 100℃, and the PH value is 6; In step S3, the silane coupling agent NH2(CH2)3Si(OC2H5)3 undergoes the following hydrolysis and condensation reaction:

6. The method for preparing a magnetic composite adhesive according to claim 3, characterized in that: In step S4, the shear emulsification time is 6h; When the epoxy resin is added, the following coupling reaction occurs with the amino group in the powder composite material: NH2-R + epoxy group → R-NH-CH2CH(OH)-O-resin chain.

7. Application of the magnetic composite glue to inductance coating, transformer external spraying, metalization of electrodes on ferrite magnetic cores, coils, bypass shielding, heat radiation conduction, magnetic core packaging, electromagnetic shielding and filters.

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