Electromagnetic shielding composite material, preparation method thereof and electromagnetic shielding shell structure

Abstract

The invention provides an electromagnetic shielding composite material, a preparation method thereof and an electromagnetic shielding shell structure, and belongs to the technical field of electromagnetic shielding. The electromagnetic shielding composite material is prepared from the following raw materials in percentage by mass: 70 to 85 percent of polymer matrix, 14.8 to 29 percent of modified filler, 0.1 to 0.5 percent of antioxidant and 0.1 to 0.5 percent of lubricant, mixing the graphene composite powder with MXene nanosheets, adding a silane coupling agent and absolute ethyl alcohol, and sequentially performing ultrasonic treatment, drying and sieving with a 100-200-mesh sieve to obtain a modified filler; wherein based on the mass of the graphene composite powder, the MXene nanosheet and the silane coupling agent, the mass percent of the graphene composite powder is 70 to 85 percent, the mass percent of the MXene nanosheet is 14 to 25 percent, and the mass percent of the silane coupling agent is 1 to 5 percent. The electromagnetic shielding composite material provided by the invention has more balanced electromagnetic shielding performance and mechanical performance.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic shielding technology, and in particular to an electromagnetic shielding composite material, a preparation method thereof, and an electromagnetic shielding shell structure. Background Art

[0002] In order to ensure that the zero-checking device can operate stably during the zero-checking and inspection tasks on insulators, it is necessary to design electromagnetic interference protection for the zero-checking device. For example, the zero-checking device should be placed in a shell made of electromagnetic shielding material. The shell can shield the strong electric and magnetic fields generated by the high voltage and large current during the operation of the transmission line, thereby improving the anti-interference ability of the zero-checking device.

[0003] In related technologies, conductive polymer composites (CPCs) materials have the advantages of light weight, low price, good molding and processing properties, and corrosion resistance. They are a new type of electromagnetic shielding material with application prospects. For example, CPCs materials are prepared by melt-blending graphene as a conductive filler with a polymer matrix and extruding and granulating it. The high-conductivity graphene filler is beneficial to improving the electromagnetic shielding performance of CPCs.

[0004] However, the mechanical properties of the CPCs materials prepared above are poor and their shielding effectiveness in high-frequency bands (such as millimeter waves and THz bands) is insufficient, which limits their application scope. Summary of the Invention

[0005] The embodiments of the present application provide an electromagnetic shielding composite material, a preparation method thereof, and an electromagnetic shielding shell structure to solve the problem that the CPCs material prepared in the related art has poor mechanical properties and insufficient shielding effectiveness in high frequency bands (such as millimeter waves and THz bands), which limits its application scope.

[0006] In a first aspect, an embodiment of the present application provides an electromagnetic shielding composite material. The raw materials of the electromagnetic shielding composite material include the following components in mass percentage: polymer matrix: 70-85%, modified filler: 14.8-29%, antioxidant: 0.1-0.5%, lubricant: 0.1-0.5%, and the sum of the mass percentages of the polymer matrix, modified filler, antioxidant, and lubricant is 100%;

[0007] The modified filler is prepared by a method comprising the following steps:

[0008] Will - Graphene composite powder is mixed with MXene nanosheets, and a silane coupling agent and anhydrous ethanol are added, and ultrasonic treatment, drying and 100-200 mesh sieve are carried out in sequence to obtain a modified filler; wherein, -The mass of graphene composite powder, MXene nanosheets and silane coupling agent is taken as the weight. - The mass percentage of graphene composite powder is 70-85%, the mass percentage of MXene nanosheets is 14-25%, and the mass percentage of silane coupling agent is 1-5%; -The sum of the mass percentages of graphene composite powder, MXene nanosheets and silane coupling agent is 100%.

[0009] In a possible implementation, the electromagnetic shielding composite material provided in the embodiment of the present application is ultrasonically treated for 1-2 hours.

[0010] In one possible implementation, the electromagnetic shielding composite material provided in the embodiment of the present application, the MXene nanosheets are prepared by a method comprising the following process:

[0011] Will Etching the powder with hydrofluoric acid at a preset temperature for a first preset time to obtain an etching solution;

[0012] The etching solution is centrifuged and washed until it becomes neutral, and ultrasonic stripping is performed for a second preset time to obtain a dispersion;

[0013] The dispersion was freeze-dried and then ball-milled to obtain single-layer MXene nanosheets.

[0014] In a possible implementation, the electromagnetic shielding composite material provided in the embodiment of the present application, the MXene nanosheet is type.

[0015] In one possible implementation, in the electromagnetic shielding composite material provided in the embodiment of the present application, the thickness of the MXene nanosheet is 1-5 nm; and / or,

[0016] The lateral size of MXene nanosheets is 0.5-5 μm.

[0017] In a possible implementation, the electromagnetic shielding composite material provided in the embodiment of the present application has a preset temperature of 35-45° C.; and / or,

[0018] The first preset duration is 20-28 hours; and / or,

[0019] The second preset duration is 1-2 hours.

[0020] In a possible implementation, the electromagnetic shielding composite material provided in the embodiments of the present application, -The graphene composite powder is prepared by a method comprising the following steps:

[0021] Graphene oxide, and Dissolve in deionized water and perform ultrasonic dispersion to obtain a precursor solution;

[0022] Ammonia water was added to the precursor solution and stirred to react to adjust the pH of the precursor solution to 9-11 to obtain -graphene oxide coprecipitated colloid;

[0023] Will -Graphene oxide coprecipitated colloid was transferred to a high pressure reactor for hydrothermal reaction to obtain - Graphene hydrothermal crude product;

[0024] right -The crude graphene hydrothermal product is subjected to magnetic separation, washing, drying and sieving in sequence to obtain nano-scale -Graphene composite powder.

[0025] In a possible implementation, the electromagnetic shielding composite material provided in the embodiment of the present application has an ultrasonic dispersion time of 30-60 minutes; and / or,

[0026] The stirring reaction time is 1-2 hours; and / or,

[0027] The temperature of the hydrothermal reaction is 170-190°C; and / or,

[0028] The hydrothermal reaction time is 10-14 hours.

[0029] In a possible implementation, the electromagnetic shielding composite material provided in the embodiments of the present application, -Graphene composite powder The mass ratio to graphene is (6-8):(2-4).

[0030] In a possible implementation, in the electromagnetic shielding composite material provided in an embodiment of the present application, the polymer matrix includes at least one of polyphenylene sulfide, polyamide, polyvinyl alcohol, and polybutylene terephthalate.

[0031] In a second aspect, an embodiment of the present application provides a method for preparing the electromagnetic shielding composite material according to the first aspect, the preparation method comprising:

[0032] The polymer matrix, modified filler, antioxidant and lubricant are premixed and melt-blended for 30-45 minutes under nitrogen protection in a twin-screw extruder at a segmented temperature of 280-320°C to form pellets through extrusion; wherein the screw speed is 19-21 r / min, and the segmented temperature of 280-320°C means that the temperature of the feeding section of the twin-screw extruder is 280-290°C, the temperature of the compression section is 290-310°C, the temperature of the mixing section is 300-320°C, and the temperature of the die section is 310-320°C;

[0033] The granulated material is pelletized and dried to a moisture content of less than 0.1% to obtain an electromagnetic shielding composite material.

[0034] In a third aspect, an embodiment of the present application provides an electromagnetic shielding shell structure, which is applied to a zero detection device. The electromagnetic shielding shell structure includes an inner shell and an outer shell arranged outside the inner shell.

[0035] The inner shell is a metal composite part, and the outer shell is made by injection molding the electromagnetic shielding composite material obtained in the second aspect according to preset injection molding parameters.

[0036] In a possible implementation, the electromagnetic shielding shell structure provided in the embodiment of the present application has preset injection molding parameters including a mold temperature of 130-150° C.; and / or,

[0037] The injection pressure is 70-90MPa.

[0038] In one possible implementation, the electromagnetic shielding shell structure provided in the embodiment of the present application, the metal composite part includes an Al-Cu-Mg alloy matrix and a filler;

[0039] The filler includes at least one of alumina, boron nitride, graphene, carbon fiber, titanium, and zirconium.

[0040] In a possible implementation, in the electromagnetic shielding shell structure provided in the embodiment of the present application, the weight percentage of the filler in the Al-Cu-Mg alloy matrix is ​​3-13%.

[0041] In a possible implementation, the electromagnetic shielding shell structure provided in the embodiment of the present application further includes a conductive base, an annular shielding conductor, and at least two capacitors;

[0042] The inner shell and the outer shell are both provided with outlets, the conductive base is detachably arranged on the outer shell, the annular shielding conductor is connected to the side of the conductive base facing away from the outer shell, and each capacitor is connected to the side of the annular shielding conductor facing away from the conductive base, and the paired capacitors are respectively located at the radial ends of the annular shielding conductor;

[0043] A through hole is provided on the conductive base, and the through hole is communicated with the line outlet through the annular shielding conductor.

[0044] In a possible implementation, in the electromagnetic shielding shell structure provided in the embodiment of the present application, the thickness of the inner shell is 1.5-2 mm, and the thickness of the outer shell is 2-2.5 mm.

[0045] The electromagnetic shielding composite material and its preparation method and electromagnetic shielding shell structure provided in the embodiment of the present application are as follows: the electromagnetic shielding composite material introduces MXene into the modified filler; MXene reacts with the -SiOH group of the silane coupling agent through its rich surface functional groups (-OH / -F) to form Si-O-Ti covalent bonds; this chemical bonding enables the silane molecules to form a dense grafting layer on the surface of MXene, so that the long-chain organic groups of the silane molecules produce a steric effect, thereby physically blocking the π-π stacking of graphene sheets and avoiding the agglomeration of graphene; in addition, through the zero-dimensional The cross-dimensional collaborative construction of nanoparticles, two-dimensional graphene and MXene forms a multi-level electromagnetic loss network in the polymer matrix. The three produce "electric-magnetic-dielectric" coupling through the interface polarization effect, broadening the effective loss band and improving the absorption efficiency of electromagnetic shielding composite materials for high-frequency waves; the covalent bonding interface established between the filler and the matrix by the silane coupling agent is not only beneficial to improve the interfacial binding energy between the modified filler and the polymer matrix, and enhance the mechanical properties of the electromagnetic shielding composite material, but also helps to reduce the sudden change in the dielectric constant of the modified filler-polymer matrix, thereby reducing the reflection loss of electromagnetic waves at the interface, so that the electromagnetic shielding composite material has more balanced electromagnetic shielding performance and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0047] Figure 1 Schematic diagram of the preparation process of MXene nanosheets provided in this application;

[0048] Figure 2 Provided for this application - Schematic diagram of the preparation process of graphene composite powder;

[0049] Figure 3 A schematic diagram of the preparation process of the electromagnetic shielding composite material provided in this application;

[0050] Figure 4 A schematic diagram of the structure of the electromagnetic shielding shell provided in this application;

[0051] Figure 5 for Figure 4 Connection diagram of the conductive base, annular shielding conductor and capacitor;

[0052] Figure 6 A diagram of the electromagnetic shielding shell structure is provided for this application.

[0053] Description of reference numerals:

[0054] 100-Electromagnetic shielding shell structure;

[0055] 110-inner shell; 120-outer shell; 121-outlet; 130-conductive base; 140-annular shielding conductor; 150-capacitor; 160-fastener;

[0056] 200-zero detection device; 300-drive circuit; 400-control circuit; 500-filter device; 600-robot gripper; 700-voltage divider; 800-fiber isolator; 900-insulator.

[0057] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0058] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0059] In order to ensure that the zero-checking device can operate stably during the zero-checking and inspection tasks on insulators, it is necessary to design electromagnetic interference protection for the zero-checking device. For example, the zero-checking device should be placed in a shell made of electromagnetic shielding material. The shell can shield the strong electric and magnetic fields generated by the high voltage and large current during the operation of the transmission line, thereby improving the anti-interference ability of the zero-checking device.

[0060] In related technologies, conductive polymer composites (CPCs) materials have the advantages of light weight, low price, good molding and processing properties, and corrosion resistance. They are a new type of electromagnetic shielding material with application prospects. For example, CPCs materials are prepared by melt-blending graphene as a conductive filler with a polymer matrix and extruding and granulating it. The high-conductivity graphene filler is beneficial to improving the electromagnetic shielding performance of CPCs.

[0061] However, the mechanical properties of the CPCs materials prepared above are poor and their shielding effectiveness in high-frequency bands (such as millimeter waves and THz bands) is insufficient, which limits their application scope.

[0062] Specifically, because graphene sheets are prone to agglomeration in the polymer matrix due to π-π stacking, a high filler content is usually required to achieve the required electromagnetic shielding effectiveness, which makes the production cost of CPCs high and the mechanical properties poor. The electrical loss of graphene is mainly achieved through carrier migration, but at high frequencies, the skin effect causes electromagnetic waves to be conducted only on its surface, and The magnetic loss will decay sharply in the frequency band above GHz due to the limitation of natural resonance frequency. In addition, the interface bonding between the filler and the matrix is ​​mainly physical adsorption, and the interface compatibility is poor, which limits the mechanical properties and high-temperature stability. At the same time, the physical adsorption interface will trigger multiple reflections of electromagnetic waves, resulting in impedance mismatch, further reducing the absorption efficiency of high-frequency waves, making it difficult to meet the broadband shielding requirements of advanced electronic equipment, limiting its application range.

[0063] In view of this, the embodiment of the present application provides an electromagnetic shielding composite material, a preparation method thereof, and an electromagnetic shielding shell structure. The electromagnetic shielding composite material introduces MXene into the modified filler. MXene reacts with the -SiOH group of the silane coupling agent through its rich surface functional groups (-OH / -F) to form a Si-O-Ti covalent bond. This chemical bonding allows the silane molecules to form a dense grafting layer on the surface of MXene, so that the long-chain organic groups of the silane molecules produce a spatial steric effect, thereby physically blocking the π-π stacking of graphene sheets and avoiding the agglomeration of graphene. In addition, through zero-dimensional The cross-dimensional collaborative construction of nanoparticles, two-dimensional graphene and MXene forms a multi-level electromagnetic loss network in the polymer matrix. The three produce "electric-magnetic-dielectric" coupling through the interface polarization effect, broadening the effective loss band and improving the absorption efficiency of electromagnetic shielding composite materials for high-frequency waves; the covalent bonding interface established between the filler and the matrix by the silane coupling agent is not only beneficial to improve the interfacial binding energy between the modified filler and the polymer matrix, and enhance the mechanical properties of the electromagnetic shielding composite material, but also helps to reduce the sudden change in the dielectric constant of the modified filler-polymer matrix, thereby reducing the reflection loss of electromagnetic waves at the interface, so that the electromagnetic shielding composite material has more balanced electromagnetic shielding performance and mechanical properties.

[0064] The following describes the embodiments of the present application with reference to the accompanying drawings.

[0065] The embodiment of the present application provides an electromagnetic shielding composite material. The raw materials of the electromagnetic shielding composite material include the following components in mass percentage: polymer matrix: 70-85%, modified filler: 14.8-29%, antioxidant: 0.1-0.5%, lubricant: 0.1-0.5%, and the sum of the mass percentages of the polymer matrix, modified filler, antioxidant, and lubricant is 100%.

[0066] The modified filler is prepared by a method comprising the following steps:

[0067] Will - Graphene composite powder is mixed with MXene nanosheets, and a silane coupling agent and anhydrous ethanol are added, and ultrasonic treatment, drying and 100-200 mesh sieve are carried out in sequence to obtain a modified filler; wherein, -The mass of graphene composite powder, MXene nanosheets and silane coupling agent is taken as the weight. - The mass percentage of graphene composite powder is 70-85%, the mass percentage of MXene nanosheets is 14-25%, and the mass percentage of silane coupling agent is 1-5%; -The sum of the mass percentages of graphene composite powder, MXene nanosheets and silane coupling agent is 100%.

[0068] Among them, the electromagnetic shielding composite material provided in the embodiments of the present application can be used in the field of power grid communications, and is used for electromagnetic shielding of key components such as base station antenna covers and mobile phone middle frames; it can also be used in the aerospace field, and is suitable for electromagnetic protection of satellite communication equipment, aircraft electronic cabins and other parts, to meet their broadband shielding needs in extreme environments; or, it can be used in the field of medical electronics, and is suitable for electromagnetic shielding of precision instruments such as magnetic resonance imaging equipment and surgical robots, to ensure the stability of equipment operation.

[0069] Specifically, in the electromagnetic shielding composite material system, through a specific ratio of The graphene composite powder and MXene nanosheets, bridged by a silane coupling agent, construct a unique multi-level electromagnetic loss network within the polymer matrix. The MXene nanosheets, with their abundant surface functional groups, form a strong chemical bond with the silane coupling agent, effectively suppressing graphene aggregation and establishing a three-dimensional continuous conductive path through their excellent electrical conductivity. The introduction of nanoparticles provides a magnetic loss mechanism, which, combined with the dielectric loss of graphene and the interfacial polarization loss of MXene, creates a triple "electromagnetic-dielectric" synergistic effect, enabling broadband electromagnetic wave absorption from low to high frequencies. The covalently bonded interface formed by the silane coupling agent between the filler and the matrix significantly enhances the material's mechanical properties while optimizing electromagnetic impedance matching and effectively reducing interfacial reflection losses.

[0070] For example, among the components of the electromagnetic shielding composite material, the mass percentage of the polymer matrix is ​​70%, the mass percentage of the modified filler is 29%, the mass percentage of the antioxidant is 0.5%, and the mass percentage of the lubricant is 0.5%; alternatively, the mass percentage of the polymer matrix is ​​75%, the mass percentage of the modified filler is 24.8%, the mass percentage of the antioxidant is 0.1%, and the mass percentage of the lubricant is 0.1%. As long as the sum of the mass percentages of the polymer matrix, modified filler, antioxidant, and lubricant is 100%, this is not limited in this embodiment of the present application.

[0071] Among them, by adding a lubricant, the lubricant can be zinc stearate. In the process of preparing the electromagnetic shielding composite material by melt blending, the lubricant can be used to reduce the melt viscosity and reduce the damage of shear force to the MXene / graphene sheet.

[0072] In some examples, among the components of the modified filler, - The mass percentage of graphene composite powder is 70%, the mass percentage of MXene nanosheets is 25%, and the mass percentage of silane coupling agent is 5%; or, -The mass percentage of graphene composite powder is 85%, the mass percentage of MXene nanosheets is 14%, and the mass percentage of silane coupling agent is 1%. The sum of the mass percentages of the graphene composite powder, MXene nanosheets, and silane coupling agent may be 100%, which is not limited in the present embodiment.

[0073] Among them, in the process of preparing the modified filler, the ultrasonic treatment step makes the MXene nanosheets and - The graphene composite powder is uniformly dispersed at the nanometer level in the liquid phase, while promoting the hydrolysis and activation of the silane coupling agent. Anhydrous ethanol is used as a solvent to ensure the effective dissolution of the silane coupling agent and improve the wettability of the filler surface through its low surface tension. The drying process is carried out at 70-90°C, a temperature range that fully removes the solvent while avoiding thermal decomposition of the silane coupling agent, ensuring the retention of its active groups. Finally, the modified filler is sieved through a 100-200 mesh sieve to control the particle size distribution, ensuring good fluidity and stacking density.

[0074] The electromagnetic shielding composite material provided in the embodiment of the present application is obtained by introducing MXene into the modified filler. The MXene reacts with the -SiOH group of the silane coupling agent through its abundant surface functional groups (-OH / -F) to form Si-O-Ti covalent bonds. This chemical bonding enables the silane molecules to form a dense graft layer on the surface of the MXene, so that the long-chain organic groups of the silane molecules produce a steric effect, which can physically block the π-π stacking of the graphene sheets and avoid the agglomeration of graphene. In addition, through the zero-dimensional The cross-dimensional collaborative construction of nanoparticles, two-dimensional graphene and MXene forms a multi-level electromagnetic loss network in the polymer matrix. The three produce "electric-magnetic-dielectric" coupling through the interface polarization effect, broadening the effective loss band and improving the absorption efficiency of electromagnetic shielding composite materials for high-frequency waves; the covalent bonding interface established between the filler and the matrix by the silane coupling agent is not only beneficial to improve the interfacial binding energy between the modified filler and the polymer matrix, and enhance the mechanical properties of the electromagnetic shielding composite material, but also helps to reduce the sudden change in the dielectric constant of the modified filler-polymer matrix, thereby reducing the reflection loss of electromagnetic waves at the interface, so that the electromagnetic shielding composite material has more balanced electromagnetic shielding performance and mechanical properties.

[0075] In some embodiments, the duration of sonication is 1-2 hours.

[0076] Thus, by setting the ultrasonic treatment time to 1-2 hours, the MXene nanosheets and -Graphene composite powder can be fully dispersed to the nanometer level, while avoiding material structure damage caused by excessive ultrasound.

[0077] Illustratively, the duration of ultrasonic treatment can be 1 hour, 1.5 hours, or 2 hours.

[0078] See Figure 1 In some examples, MXene nanosheets are prepared by a method comprising:

[0079] S101, will The powder is etched with hydrofluoric acid at a preset temperature for a first preset time to obtain an etching solution.

[0080] Thus, the selective removal of The Al atomic layers in the MXene form multilayers.

[0081] S102 , washing the etching solution by centrifugation until it becomes neutral, and performing ultrasonic stripping for a second preset time to obtain a dispersion.

[0082] In this way, the etching solution is centrifuged and washed to neutrality to more thoroughly remove the residual hydrofluoric acid and By-products are produced, thus avoiding the oxidative degradation of MXene in subsequent processes; multilayer MXene can be dissociated into a single-layer structure through the ultrasonic exfoliation step.

[0083] S103, freeze-drying the dispersion and then ball-milling to obtain a single-layer MXene nanosheet.

[0084] Here, freeze-drying is used to maintain the porous structure of the MXene sheet, and subsequent ball milling treatment (the rotation speed can be 200-400 rpm, with argon protection) can further depolymerize the small amount of residual multilayer agglomerates, ultimately obtaining evenly dispersed single-layer MXene nanosheets.

[0085] The preset temperature is 35-45° C.; and / or the first preset time is 20-28 hours; and / or the second preset time is 1-2 hours.

[0086] Specifically, the etching temperature of 35-45°C is used to ensure that the hydrofluoric acid The Al layer in the middle is fully etched, and the oxidation of the MXene layer caused by the temperature exceeding 45°C is avoided; the etching time of 20-28 hours ensures the complete removal of the Al layer and prevents the collapse of the MXene structure caused by the etching time exceeding 28 hours; the ultrasonic stripping of 1-2 hours efficiently dissociates the multi-layer MXene into a single-layer structure through the cavitation effect, avoiding the increase of MXene defects caused by the ultrasonic time exceeding 2 hours.

[0087] In a specific example, the MXene nanosheets are type.

[0088] in, The MXene nanosheets of this type have more abundant -OH / -F functional groups, i.e., about 5-8 per nm², which can efficiently condense with silane coupling agents to form Ti-O-Si covalent bonds, thereby improving the filler-matrix interface bonding strength. In addition, The MXene nanosheets have good electrical conductivity and structural stability.

[0089] In practical applications, the thickness of the MXene nanosheet is 1-5 nm; and / or the lateral size of the MXene nanosheet is 0.5-5 μm.

[0090] Specifically, a thickness of 1-5 nm ensures that the MXene maintains a high specific surface area, providing ample bonding sites for the silane coupling agent. It also aligns the electromagnetic skin depth with the wavelength of high-frequency signals, reducing surface reflection losses. A lateral dimension of 0.5-5 μm is designed to ensure sufficient structural integrity of the MXene flakes.

[0091] Exemplarily, the thickness of the MXene nanosheet is 1 nm, 2 nm, 3 nm, 4 nm, 4.5 nm or 5 nm; the lateral size of the MXene nanosheet is 0.5 μm, 0.8 μm, 1 μm, 2 μm, 3 μm 4 μm or 5 μm.

[0092] See Figure 2 , in some embodiments, -The graphene composite powder is prepared by a method comprising the following steps:

[0093] S201, graphene oxide, and The precursor solution was dissolved in deionized water and ultrasonically dispersed to obtain a precursor solution.

[0094] In this way, graphene oxide is uniformly dispersed and adsorbed by the cavitation effect during ultrasonic dispersion. ions, providing homogeneous nucleation sites for subsequent in situ reactions.

[0095] S202, adding ammonia water to the precursor solution and stirring the reaction to adjust the pH of the precursor solution to 9-11, to obtain -graphene oxide coprecipitated colloids.

[0096] In this way, to encourage Nanoparticles are evenly anchored on the defect sites of graphene sheets, and the OH⁻ provided by ammonia can regulate crystallinity and can also partially reduce graphene oxide.

[0097] S203, will -Graphene oxide coprecipitated colloid was transferred to a high pressure reactor for hydrothermal reaction to obtain - Graphene hydrothermal crude product.

[0098] Among them, the hydrothermal reaction can be completed simultaneously Crystallization and deep reduction of graphene promote Form Fe-OC chemical bonding with graphene.

[0099] S204, yes -The crude graphene hydrothermal product is subjected to magnetic separation, washing, drying and sieving in sequence to obtain nano-scale -Graphene composite powder.

[0100] Here, the highly magnetic complex can be selectively recovered by magnetic separation and the unreacted ions can be removed by ethanol washing to obtain Uniform load and strong interface bonding -Graphene composite powder, dried and sieved to maintain -Activity and fluidity of graphene composite powders.

[0101] The ultrasonic dispersion is performed for 30-60 minutes; and / or the stirring reaction is performed for 1-2 hours; and / or the hydrothermal reaction temperature is 170-190° C.; and / or the hydrothermal reaction is performed for 10-14 hours.

[0102] Specifically, 30-60 minutes of ultrasonic dispersion can ensure that graphene oxide is fully dissociated and Uniform adsorption of ions; 1-2 hours of stirring reaction is conducive to the full diffusion of ammonia and completion of Homogeneous nucleation; 170-190℃ hydrothermal temperature can drive the effective reduction of graphene oxide; 10-14 hours of hydrothermal time can ensure The crystals grow fully and form a stable Fe-OC bonding interface with graphene.

[0103] Illustratively, the duration of ultrasonic dispersion is 30 minutes, 35 minutes, 40 minutes, 50 minutes or 60 minutes.

[0104] The reaction was stirred for 1 hour, 1.2 hours, 1.5 hours or 2 hours.

[0105] The temperature of the hydrothermal reaction is 170°C, 175°C, 180°C, 185°C or 190°C.

[0106] The duration of the hydrothermal reaction is 10 hours, 11 hours, 12 hours, 13 hours or 14 hours.

[0107] In some embodiments, -Graphene composite powder The mass ratio to graphene is (6-8):(2-4).

[0108] So, the higher The proportion (60-80wt%) ensures that the electromagnetic shielding composite material has strong magnetic loss capability, and the moderate graphene content (20-40wt%) can provide a continuous conductive network in the polymer matrix to enhance the medium and high frequency conductivity loss, and can also avoid the magnetic dilution effect caused by excessive graphene.

[0109] For example, The mass ratio of titanium dioxide to graphene is 6:2, 6:3, 6:4, 7:3, 7:4 or 8:4.

[0110] In a specific example, the polymer matrix includes at least one of polyphenylene sulfide, polyamide, polyvinyl alcohol, and polybutylene terephthalate.

[0111] Among them, polyphenylene sulfide has good high-temperature resistance; polyamide has high tensile strength and good mechanical properties; the water-soluble properties of polyvinyl alcohol facilitate solution processing into film, which can be suitable for application scenarios of flexible electronic shielding; polybutylene terephthalate has a fast crystallization rate, which is beneficial to improving the molding efficiency of magnetic shielding composite materials.

[0112] See Figure 3 , the present application embodiment provides a method for preparing the electromagnetic shielding composite material in any of the above embodiments, the preparation method comprising:

[0113] S301. Premix the polymer matrix, modified filler, antioxidant and lubricant, and then melt-blend them for 30-45 min under nitrogen protection at a segmented temperature of 280-320°C through a twin-screw extruder to form pellets; wherein the screw speed is 19-21 r / min, and the segmented temperature of 280-320°C means that the temperature of the feeding section of the twin-screw extruder is 280-290°C, the temperature of the compression section is 290-310°C, the temperature of the mixing section is 300-320°C, and the temperature of the die section is 310-320°C.

[0114] Among them, by setting the temperature of the feeding section to 280-290°C, overload melting and bonding of the components can be avoided, and the stability of the feed can be determined; by setting the temperature of the compression section to 290-310°C, the polymer matrix can be melted; by setting the temperature of the mixing section to 300-320°C, the melt fluidity can be improved and the viscosity can be reduced; by setting the temperature of the die section to 310-320°C, the fluidity can be maintained for uniform extrusion and granulation.

[0115] By protecting the melt blending for 30-45 min with nitrogen, the thermal oxidation of MXene and graphene under screw shearing can be suppressed.

[0116] By setting the screw speed to 19-21 r / min, the structural integrity of graphene can be protected while ensuring the dispersion of the modified filler in the polymer matrix.

[0117] S302, granulating and drying the granules to a moisture content of less than 0.1%.

[0118] In this way, the pore defects in the prepared electromagnetic shielding composite material can be eliminated.

[0119] Example 1:

[0120] (1) -Preparation of graphene composite powder:

[0121] 1g graphene oxide, 3.6g , 1.4g Dissolve in 200 mL of water and sonicate for 30 min; add 10 mL of ammonia water to adjust the pH to 10, stir for 1 h, heat at 180°C for 12 h, and pass through a 200-mesh sieve after drying.

[0122] (2) Preparation of MXene nanosheets:

[0123] 10g The product was reacted with 100 mL of 40% hydrofluoric acid at 40 °C for 24 h, ultrasonically stripped for 1 h, and freeze-dried for 48 h.

[0124] (3) Preparation of modified fillers:

[0125] mix -Graphene composite powder (15%) and MXene nanosheets (5%), added with 0.5% silane coupling agent KH-550 and anhydrous ethanol, ultrasonicated for 1h, and dried at 80℃.

[0126] (4) Preparation of electromagnetic shielding composite materials:

[0127] The polyphenylene sulfide matrix, modified filler, antioxidant, and lubricant were premixed and extruded into pellets through a twin-screw extruder at 280°C in the feeding section, 300°C in the compression section, 310°C in the mixing section, and 310°C in the die section. The pellets were melt-blended for 30 minutes under nitrogen protection at a screw speed of 20 rpm. The pellets were cut and dried to a moisture content of less than 0.1%.

[0128] Example 2:

[0129] The preparation of graphene composite powder, MXene nanosheets and electromagnetic shielding composite materials is the same as in Example 1. The preparation process of the modified filler in Example 2 is as follows:

[0130] mix -Graphene (20%) and MXene (3%), added with 0.5% silane coupling agent KH-550KH-550 and anhydrous ethanol, ultrasonicated for 1h, and dried at 80℃.

[0131] Example 3:

[0132] The preparation of graphene composite powder, MXene nanosheets and electromagnetic shielding composite materials is the same as in Example 1. The preparation process of the modified filler in Example 3 is as follows:

[0133] mix -Graphene (20%) and MXene (4%), added with 0.5% silane coupling agent KH-550KH-550 and anhydrous ethanol, ultrasonicated for 1h, and dried at 80℃.

[0134] Comparative Example 1:

[0135] During the process of preparing the electromagnetic shielding composite material in Example 1, no lubricant was added.

[0136] Comparative Example 2:

[0137] During the preparation of the modified filler in Example 1, no MXene nanosheets were added.

[0138] Comparative Example 3:

[0139] During the preparation of the electromagnetic shielding composite material in Example 1, no nitrogen was passed during melt blending, and the screw speed was 100 r / min.

[0140] The components used in preparing the electromagnetic shielding composite materials in Examples 1-3 and Comparative Examples 1-3 are shown in the following table.

[0141]

[0142] The broadband shielding effectiveness of Examples 1-3 and Comparative Examples 1-3 was tested according to GB / T 12190-2021 and GB / T 30142-2013 standards: Examples 1-3 achieved broadband shielding effectiveness of 72dB, 68dB, and 69dB, respectively; while Comparative Examples 1-3 achieved broadband shielding effectiveness of 61dB, 47dB, and 42dB, respectively. The test results show that Examples 1-3 exhibit superior shielding effectiveness compared to Comparative Examples 1-3. In Comparative Example 1, the absence of zinc stearate as a lubricant resulted in a high melt viscosity and poor dispersion. In Comparative Example 2, the absence of MXene as a modified filler significantly reduced the conductivity of Comparative Example 2. In Comparative Example 3, the lack of nitrogen flow and the use of a low screw speed of 20 r / min resulted in partial oxidation of the material and excessive shear stress, resulting in inferior shielding effectiveness compared to Examples 1-3.

[0143] Furthermore, Examples 1-3 are superior to the comparative examples in terms of mechanical properties, high temperature stability and frequency band adaptability.

[0144] Tensile strength tests showed that Example 1 achieved 92 MPa, representing increases of 18%, 42%, and 59% over Comparative Examples 1 (78 MPa), 2 (65 MPa), and 3 (58 MPa), respectively. This is attributed to the enhanced interface strength achieved by the covalently bonded network constructed between the MXene and silane coupling agent. Thermogravimetric analysis revealed that Example 1 experienced only 1.2% mass loss at 300°C, significantly lower than the 4.5% observed in Comparative Example 3 (due to inadequate nitrogen protection leading to increased thermal oxidation). Vector network analyzer (VNA) testing revealed that Example 1 exhibited 75% absorption loss in the millimeter-wave frequency band (30 GHz), while Comparative Example 2, lacking the dielectric polarization effect of the MXene, exhibited only 38% absorption loss. Furthermore, the impedance matching parameter (input impedance / free-space impedance = 0.9) of Example 1 was closer to the ideal value of 1 than that of Comparative Examples 1-3 (input impedance / free-space impedance = 1.4, 1.7, and 2.1, respectively), confirming that its interface design effectively reduced electromagnetic wave reflection.

[0145] See Figures 4 to 6 The embodiment of the present application also provides an electromagnetic shielding shell structure 100, which is applied to the zero detection device 200. The electromagnetic shielding shell structure 100 includes an inner shell 110 and an outer shell 120 arranged on the outside of the inner shell 110; the inner shell 110 is a metal composite part, and the outer shell 120 is made by injection molding the granules after drying in the above embodiment according to preset injection molding parameters.

[0146] The zero-check device 200 can be disposed within the inner housing 110, which can also integrate a drive circuit 300, a control circuit 400, and a filter device 500. The filter device 500 is connected to the external robot gripper 600 via a shielded cable to block on-site electromagnetic interference, enabling milliampere-level leakage current detection on the insulator 900 in strong electromagnetic field environments (such as substations). The zero-check device 200 serves as the core sensing unit, employing microcurrent detection technology to monitor the surface leakage current of the insulator 900 in real time. The control circuit 400 includes a built-in 24-bit analog-to-digital converter (ADC) module, which converts the analog signal collected by the zero-check device 200 into a digital signal and eliminates baseline drift through a digital filtering algorithm. The drive circuit 300 controls the servo motor that drives the robot gripper 600 via a pulse width modulation (PWM) signal to precisely adjust the contact pressure of the robot gripper 600, ensuring stable contact between the detection probe and the surface of the insulator 900.

[0147] Furthermore, a voltage divider 700 and an optical fiber isolator 800 are integrated on the side wall of the outer shell 120 to achieve interference-free transmission of signals.

[0148] In this way, the inner shell 110 has high rigidity and anti-deformation ability, which can provide stable physical support for the internal zero-checking device 200, etc., to avoid displacement or damage due to external force impact or vibration; the outer shell 120 is made by injection molding the granulation after drying in the above embodiment with preset injection molding parameters. Compared with the increase in the amount of metal material, it can fully utilize the lightweight advantages of the electromagnetic shielding composite material, which is conducive to making the electromagnetic shielding shell structure 100 as a whole lighter and easier to carry and operate.

[0149] For example, the inner shell 110 reflects low-frequency electromagnetic waves (1-10 GHz SE > 50 dB) through free electron oscillation, and the MXene / graphene three-dimensional network in the outer shell 120 absorbs high-frequency electromagnetic waves (millimeter wave band SE > 65 dB) through dielectric loss and interface polarization. The combination of the two enables the overall shielding effectiveness to cover a wide frequency band from DC to 40 GHz, thereby improving the adaptability of the electromagnetic shielding shell structure 100.

[0150] The preset injection molding parameters include a mold temperature of 130-150° C. and / or an injection pressure of 70-90 MPa.

[0151] Thus, by setting the mold temperature to 130-150°C, the polymer matrix can achieve a moderate degree of crystallinity during cooling, avoiding internal stress caused by rapid crystallization at low temperatures (<120°C) and deformation during demolding caused by high temperatures (>160°C). Exemplary mold temperatures are 130°C, 140°C, 145°C, 147°C, or 150°C.

[0152] By setting the injection pressure to 70-90 MPa, the filler melt can more fully fill the mold cavity and avoid damage to the filler structure caused by excessive pressure (>100 MPa). For example, the injection pressure is 70 MPa, 75 MPa, 85 MPa, or 90 MPa.

[0153] In some examples, the metal composite includes an Al-Cu-Mg alloy matrix and a filler; the filler includes at least one of aluminum oxide, boron nitride, graphene, carbon fiber, titanium, and zirconium.

[0154] Among them, the Al-Cu-Mg alloy matrix has high specific strength and good thermal conductivity; alumina nanoparticles increase the microhardness of the Al-Cu-Mg alloy matrix and reduce the thermal expansion coefficient by pinning the grain boundaries; the layered structure of boron nitride can form a self-lubricating effect during cutting; graphene and carbon fiber construct a three-dimensional conductive network to improve the reflection efficiency of low-frequency electromagnetic waves; titanium / zirconium refiners refine the grain size of the Al-Cu-Mg alloy matrix through heterogeneous nucleation, which is beneficial to improve fatigue resistance.

[0155] Next, a manufacturing process of the inner shell 110 will be described.

[0156] Specifically, the metal composite includes the following components in mass percentage: Al-Cu-Mg alloy: addition amount 87.5%; aluminum oxide nanoparticles: particle size 50-100 nm, addition amount 5%; boron nitride nanoparticles: particle size 80-150 nm, addition amount 2%; graphene: addition amount 2%; carbon fiber: diameter 10-20 μm, length 50-100 μm, addition amount 3%; grain refiner: titanium particles, addition amount 0.5%.

[0157] The nanoparticles were first pretreated: a thin carbon layer was deposited on the surface of aluminum oxide nanoparticles via chemical vapor deposition to enhance their bonding with the aluminum alloy. A silicon dioxide coating was formed on the surface of boron nitride nanoparticles via a sol-gel method to improve their dispersion and stability. Graphene was dispersed ultrasonically and polyethylene glycol was added to further enhance its dispersion. Carbon fibers were oxidized to enhance their surface activity.

[0158] The Al-Cu-Mg alloy is then heated to 750°C to fully melt, and an inert gas (such as argon) is introduced to prevent oxidation. Pretreated alumina nanoparticles, boron nitride nanoparticles, graphene, and carbon fibers are gradually added, with rigorous stirring to ensure uniform particle distribution and prevent agglomeration. Appropriate amounts of titanium or zirconium particles are also added as grain refiners to further optimize the material's microstructure.

[0159] Furthermore, during the casting and molding process, the blank is cast using a steel mold preheated to 150°C, then naturally cooled to room temperature and water-cooled. Subsequently, the blank is subjected to machining processes such as milling and grinding to prepare the desired inner shell 110 structure.

[0160] Furthermore, the billet is heat treated, including intermediate annealing, solution treatment, and aging treatment. The intermediate annealing heats the billet to 450°C for 12 hours to eliminate casting stress. The solution treatment heats the sample to 600°C, holds it for 24 hours, and then cools it with water or air. The aging treatment is then held at 150°C for 48 hours to further optimize the material's strength and electromagnetic shielding performance. To ensure the stability of the material's properties, a secondary aging treatment is also performed at 200°C for 24 hours.

[0161] Finally, the heat-treated blank undergoes mechanical processing and surface treatment. A conductive coating (such as silver or copper, with a thickness of 0.1 mm to 0.5 mm) is applied to the sample surface via magnetron sputtering or electroplating to enhance electromagnetic shielding. The sample surface is then cleaned with acetone and mechanically polished to ensure a smooth surface. This results in the inner shell 110, which exhibits excellent electromagnetic shielding performance.

[0162] In some examples, the filler accounts for 3-13% by weight of the Al-Cu-Mg alloy matrix.

[0163] In this way, it can be ensured that fillers (such as aluminum oxide, boron nitride, etc.) form a continuous interaction network in the Al-Cu-Mg alloy matrix, and it can be avoided that excessive addition of fillers leads to a decrease in melt fluidity and a decrease in processing performance.

[0164] Illustratively, the filler accounts for 3%, 5%, 7%, 8%, 11% or 13% by weight of the Al-Cu-Mg alloy matrix.

[0165] See Figures 4 to 6 In some embodiments, the electromagnetic shielding shell structure 100 further includes a conductive base 130, an annular shielding conductor 140 and at least two capacitors 150; a line outlet 121 is provided on both the inner shell 110 and the outer shell 120, the conductive base 130 is detachably provided on the outer shell 120, the annular shielding conductor 140 is connected to the side of the conductive base 130 facing away from the outer shell 120, each capacitor 150 is connected to the side of the annular shielding conductor 140 facing away from the conductive base 130, and the paired capacitors 150 are respectively located at the radial ends of the annular shielding conductor 140; a through hole is provided on the conductive base 130, and the through hole is connected to the line outlet 121 through the annular shielding conductor 140.

[0166] In this way, by installing the conductive base 130, the annular shielding conductor 140 and multiple capacitors 150 at the outlet 121 to form a full-circle conductive contact with the electromagnetic shielding shell structure 100, the electromagnetic interference in the shielded inner shell 110 can be significantly suppressed, with a good filtering effect.

[0167] The conductive base 130 may be a copper base, which is detachably mounted on the outer shell 120 via fasteners 160 such as screws; the annular shielding conductor 140 may be a copper ring.

[0168] In a specific implementation, the paired capacitors 150 are located at the radial ends of the annular shielding conductor 140. The number of capacitors 150 is set to an even number, such as 2, 4, 6, or 8. The capacitance of the two diagonal capacitors 150 located at the radial ends of the annular shielding conductor 140 is equal. This ensures that high-frequency interference noise (such as common-mode noise) at the outlet 121 is discharged to the ground through a symmetrical path, avoiding unbalanced discharge due to capacitance differences, thereby reducing electromagnetic radiation asymmetry, reducing transmission line impedance mutations, and improving high-frequency signal integrity. At the same time, the ground potential of each port of the electromagnetic shielding shell structure 100 is maintained balanced, preventing secondary radiation or interference with sensitive circuits due to ground potential fluctuations. In addition, the resonant frequency is ensured to be consistent, avoiding asymmetric gaps in the filter band.

[0169] In some embodiments, the thickness of the inner shell 110 is 1.5-2 mm, and the thickness of the outer shell 120 is 2-2.5 mm.

[0170] In this way, the structural design of the electromagnetic shielding shell structure 100 is made more reasonable, achieving a balance between electromagnetic shielding effectiveness and structural lightweight.

[0171] Illustratively, the thickness of the inner shell 110 is 1.5 mm, 1.6 mm, 1.8 mm, or 2 mm; the thickness of the outer shell 120 is 2 mm, 2.1 mm, 2.2 mm, 2.4 mm, or 2.5 mm.

[0172] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. An electromagnetic shielding composite material, characterized in that: The raw materials of the electromagnetic shielding composite material include the following components in mass percentage: polymer matrix: 70-85%, modified filler: 14.8-29%, antioxidant: 0.1-0.5%, lubricant: 0.1-0.5%, and the sum of the mass percentages of the polymer matrix, the modified filler, the antioxidant, and the lubricant is 100%; The modified filler is prepared by a method comprising the following steps: Will - Graphene composite powder is mixed with MXene nanosheets, and a silane coupling agent and anhydrous ethanol are added, and ultrasonic treatment, drying and 100-200 mesh sieve are carried out in sequence to obtain the modified filler; wherein, the modified filler is obtained by - The mass of the graphene composite powder, the MXene nanosheets and the silane coupling agent is - The mass percentage of the graphene composite powder is 70-85%, the mass percentage of the MXene nanosheets is 14-25%, and the mass percentage of the silane coupling agent is 1-5%; The sum of the mass percentages of the graphene composite powder, the MXene nanosheets, and the silane coupling agent is 100%.

2. The electromagnetic shielding composite material according to claim 1, characterized in that: The duration of the ultrasonic treatment is 1-2 hours.

3. The electromagnetic shielding composite material according to claim 1, characterized in that: The MXene nanosheets are prepared by a method comprising the following steps: Will Etching the powder with hydrofluoric acid at a preset temperature for a first preset time to obtain an etching solution; The etching solution is centrifuged and washed until it becomes neutral, and ultrasonic stripping is performed for a second preset time to obtain a dispersion; The dispersion is freeze-dried and then ball-milled to obtain single-layer MXene nanosheets.

4. The electromagnetic shielding composite material according to claim 3, characterized in that: The MXene nanosheets are type.

5. The electromagnetic shielding composite material according to claim 3, characterized in that: The thickness of the MXene nanosheet is 1-5 nm; and / or, The lateral size of the MXene nanosheets is 0.5-5 μm.

6. The electromagnetic shielding composite material according to claim 3, characterized in that: The preset temperature is 35-45°C; and / or, The first preset duration is 20-28 hours; and / or, The second preset duration is 1-2 hours.

7. The electromagnetic shielding composite material according to any one of claims 1 to 6, characterized in that: described -The graphene composite powder is prepared by a method comprising the following steps: Graphene oxide, and Dissolve in deionized water and perform ultrasonic dispersion to obtain a precursor solution; Ammonia water was added to the precursor solution and stirred to react to adjust the pH of the precursor solution to 9-11 to obtain -graphene oxide coprecipitated colloid; Will -Graphene oxide coprecipitated colloid was transferred to a high pressure reactor for hydrothermal reaction to obtain - Graphene hydrothermal crude product; right -The crude graphene hydrothermal product is subjected to magnetic separation, washing, drying and sieving in sequence to obtain nano-scale -Graphene composite powder.

8. The electromagnetic shielding composite material according to claim 7, characterized in that: The duration of the ultrasonic dispersion is 30-60 minutes; and / or, The stirring reaction lasts for 1-2 hours; and / or, The temperature of the hydrothermal reaction is 170-190° C.; and / or, The duration of the hydrothermal reaction is 10-14 hours.

9. The electromagnetic shielding composite material according to claim 7, characterized in that: described -Graphene composite powder The mass ratio to graphene is (6-8):(2-4).

10. The electromagnetic shielding composite material according to any one of claims 1 to 6, characterized in that: The polymer matrix includes at least one of polyphenylene sulfide, polyamide, polyvinyl alcohol and polybutylene terephthalate.

11. A method for preparing the electromagnetic shielding composite material according to any one of claims 1 to 10, characterized in that: The preparation method comprises: After premixing the polymer matrix, modified filler, antioxidant and lubricant, melt blending the mixture for 30-45 minutes through a twin-screw extruder under nitrogen protection at a segmented temperature of 280-320°C for extrusion into pellets; wherein the screw speed is 19-21 r / min, and the segmented temperature of 280-320°C means that the temperature of the feeding section of the twin-screw extruder is 280-290°C, the temperature of the compression section is 290-310°C, the temperature of the mixing section is 300-320°C, and the temperature of the die section is 310-320°C; The granulation and pelletizing are carried out and dried until the moisture content is less than 0.1% to obtain the electromagnetic shielding composite material.

12. An electromagnetic shielding shell structure, used in a zero detection device, characterized in that: The electromagnetic shielding shell structure includes an inner shell and an outer shell sleeved outside the inner shell; The inner shell is a metal composite part, and the outer shell is made by injection molding the electromagnetic shielding composite material obtained in claim 11 using preset injection molding parameters.

13. The electromagnetic shielding shell structure according to claim 12, characterized in that: The preset injection molding parameters include a mold temperature of 130-150° C.; and / or, The injection pressure is 70-90MPa.

14. The electromagnetic shielding shell structure according to claim 12, characterized in that: The metal composite part includes an Al-Cu-Mg alloy matrix and a filler; The filler includes at least one of aluminum oxide, boron nitride, graphene, carbon fiber, titanium and zirconium.

15. The electromagnetic shielding shell structure according to claim 14, characterized in that: The filler accounts for 3-13% by weight of the Al-Cu-Mg alloy matrix.

16. The electromagnetic shielding shell structure according to any one of claims 12 to 15, characterized in that: Also included is a conductive base, an annular shield conductor, and at least two capacitors; The inner shell and the outer shell are both provided with a wire outlet, the conductive base is detachably provided on the outer shell, the annular shielding conductor is connected to a side of the conductive base facing away from the outer shell, each of the capacitors is connected to a side of the annular shielding conductor facing away from the conductive base, and the paired capacitors are respectively located at the radial ends of the annular shielding conductor; A through hole is provided on the conductive base, and the through hole is connected with the outlet through the annular shielding conductor.

17. The electromagnetic shielding shell structure according to any one of claims 12 to 15, characterized in that: The thickness of the inner shell is 1.5-2 mm, and the thickness of the outer shell is 2-2.5 mm.

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