Nanocarbon-copper heterogeneous interface construction method for improving electromagnetic shielding and heat-conducting properties of graphene / magnesium composite material and composite material based on nanocarbon-copper heterogeneous interface construction method

Abstract

The invention discloses a nanocarbon-copper heterogeneous interface construction method for improving the electromagnetic shielding and heat-conducting properties of a graphene / magnesium composite material and a composite material based on the nanocarbon-copper heterogeneous interface construction method, and belongs to the technical field of heterogeneous interfaces. The method comprises the following steps: mixing intrinsic graphene, a surfactant and a foaming agent, performing ultrasonic dispersion treatment in solvent water, and performing freeze drying to obtain an intrinsic graphene preform; performing chemical vapor deposition on the intrinsic graphene preform serving as a substrate, and performing in-situ deposition of nanocarbon on the surface of the intrinsic graphene preform to obtain an intrinsic graphene-nanocarbon preform; a copper-containing oxidizing agent and a reducing agent are added into ethyl alcohol for ultrasonic treatment, an ethyl alcohol solution is obtained, the intrinsic graphene-nanocarbon prefabricated body is added into the ethyl alcohol solution, standing and drying treatment are conducted, then heat treatment is conducted, and an intrinsic graphene-multi-dimensional nanocarbon-nanocopper prefabricated body is obtained; and heating is conducted under argon protection, a magnesium alloy matrix is placed on the intrinsic graphene-multi-dimensional nano carbon-nano copper prefabricated body for liquid-solid infiltration extrusion, and the intrinsic graphene reinforced magnesium-based composite material is obtained. The method is used for solving the problems that existing intrinsic graphene of a three-dimensional network structure cannot have excellent electromagnetic shielding performance and heat-conducting performance at the same time, and existing magnesium-based composite materials only conduct single electromagnetic shielding performance or heat-conducting performance regulation and control.

Description

Technical Field

[0001] The present invention belongs to the technical field of heterogeneous interfaces, and specifically relates to a method for constructing a nano-carbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite material, and a composite material based thereon. Background Art

[0002] The rapid development of 5G communication technology has increased the demand for multifunctional, compact, integrated electronic devices (packaged antennas, electronic circuits, and silicon chips). To ensure the stable operation of these devices in the X-band (8.2-12.4 GHz), the development of materials with both excellent electromagnetic shielding and thermal conductivity is crucial. Three-dimensional graphene networks offer excellent electromagnetic shielding properties, but their porous nature makes them thermally insulative and difficult to load-bearing as a rigid material. Filling the pores of three-dimensional graphene networks with a liquid, high-rigidity material (magnesium alloy) to create graphene-reinforced magnesium-based composites, which enable the magnesium alloy to both bear loads and transfer heat, is an effective approach to addressing the limitations of three-dimensional porous graphene in achieving both rigidity and thermal conductivity. However, poor wettability and bonding between the graphene reinforcement and the magnesium alloy matrix limit electrical and thermal transfer at the interface, hindering improvements in the composite's electromagnetic shielding and thermal conductivity.

[0003] The paper "GO / MgO / Mg interfacemediated strengthening and electromagnetic interference shielding in AZ31 composite" (DOI: 10.1016 / j.jma.2023.07.001), published in the Journal of Magnesium and Alloys, reports a method for coating graphene oxide (GO) with a SnO2 coating. This method modifies the interface between the GO reinforcement and the AZ31 matrix by in-situ generation of a MgO layer. The GO multilayer structure and MgO interlayer increase electromagnetic wave multiple reflections and interfacial polarization, significantly enhancing the composite's electromagnetic shielding performance. Chinese invention patent publication number CN110551909A discloses a method for improving the thermal conductivity of a magnesium-based composite using nanodiamonds, and a magnesium-based composite. Ultrasonic dispersion is used to uniformly disperse nanodiamonds in a magnesium alloy matrix. The nanodiamond-reinforced magnesium-based composite is then prepared by vacuum hot pressing and high-temperature high-pressure treatment. A carbide layer is generated at the interface between the nanodiamond and magnesium alloy matrix to enhance interfacial bonding strength, reduce interfacial defects, and increase interfacial thermal conductivity.

[0004] As can be seen from the above, in order to improve the electromagnetic shielding and thermal conductivity of magnesium-based composites, most researchers currently start from the perspective of improving interface bonding and only conduct single-performance research on the electromagnetic shielding and thermal conductivity of magnesium-based composites. They cannot improve the electromagnetic shielding and thermal conductivity at the same time, which limits the application of magnesium-based composites in the multifunctional needs of small integrated electronic devices (packaged antennas, electronic circuits and silicon chips). Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for constructing a nanocarbon-copper heterogeneous interface and a composite material based thereon to improve the electromagnetic shielding and thermal conductivity of graphene / magnesium composites, and to construct an intrinsic graphene preform with a three-dimensional network structure in a magnesium alloy matrix. Electrons and heat flow can be efficiently transmitted along the three-dimensional connected network structure to meet the requirements of 5G communication technology for the multifunctionality of small integrated electronic devices, and to solve the problem that graphene with a three-dimensional network structure cannot have both excellent electromagnetic shielding performance and thermal conductivity.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite, comprising the following steps: The intrinsic graphene, surfactant and foaming agent are mixed, and then solvent water is added for ultrasonic dispersion to obtain a solution, and the solution is freeze-dried to obtain an intrinsic graphene preform; The intrinsic graphene preform is used as a substrate for chemical vapor deposition, and nanocarbon is in situ deposited on the surface of the substrate to obtain an intrinsic graphene-nanocarbon preform; wherein the nanocarbon is one or more of 1D nanocarbon and 2D nanocarbon; A copper-containing oxidizing agent and a reducing agent are added to ethanol and ultrasonically treated to obtain an ethanol solution, an intrinsic graphene-nanocarbon preform is placed in the ethanol solution, and the preform is allowed to stand in a vacuum environment. The intrinsic graphene-nanocarbon preform is then taken out and dried in an air environment at room temperature, and then heat-treated. Nanocopper is in situ grafted onto the surface of the intrinsic graphene-nanocarbon preform to obtain an intrinsic graphene-multidimensional nanocarbon-nanocopper preform; wherein the nanocopper is one or more of 0D nanocopper and 1D nanocopper; and wherein the nanocarbon and nanocopper in the intrinsic graphene-multidimensional nanocarbon-nanocopper preform have different dimensions; The magnesium alloy matrix is heated under argon protection, and liquid-solid infiltration and extrusion are performed on the intrinsic graphene-multidimensional nanocarbon-nanocopper preform to obtain an intrinsic graphene reinforced magnesium-based composite material.

[0007] In one embodiment, the surfactant is one or more of sodium carboxymethyl cellulose, riboflavin sodium phosphate, and polyvinyl pyrrolidone; and the foaming agent is sodium bicarbonate or sodium lauryl sulfate.

[0008] In one embodiment, the mass ratio of the surfactant, the intrinsic graphene, and the foaming agent is 1:(15-30):(30-250); and the concentration of the intrinsic graphene in the solution is 5-20 mg / mL.

[0009] In one embodiment, the process parameters of the chemical vapor deposition are as follows: The oxygen-containing carbon source is one or more of methanol, ethanol, and propanol; the oxygen-free carbon source is one or more of methane, ethylene, propylene, and acetylene; the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is (1-20):1; the chemical vapor deposition temperature is 850-1500°C, and the chemical vapor deposition time is 1-20 h.

[0010] In one embodiment, the copper-containing oxidant is copper nitrate dihydrate or copper chloride dihydrate; the reducing agent is one or more of hydrazine hydrate and hexadecylamine; the concentration of the copper-containing oxidant is 0.05~0.50 mol / L; and the concentration of the reducing agent is 0.01~0.50 g / mL.

[0011] In one embodiment, the power of the ultrasonic treatment is 100-500 W, and the ultrasonic treatment time is 10-30 min; the static treatment is carried out in a vacuum drying oven under a vacuum environment, the vacuum degree of the vacuum drying oven is 1-50 Pa, and the static treatment time is 6-24 h; the drying time in room temperature air environment is 24-48 h.

[0012] In one embodiment, the heat treatment process is as follows: Argon is introduced into the heat treatment furnace while the temperature is increased until the holding temperature is reached, and then a hydrogen-argon mixture is introduced into the heat treatment furnace for holding. After the holding temperature is completed, the introduction of the hydrogen-argon mixture is stopped, and only argon is introduced into the heat treatment furnace while the temperature is lowered. The holding temperature is 100-650 °C, and the holding time is 0.5-3 h. The flow ratio of hydrogen to argon in the hydrogen-argon mixture is 1:(8-30).

[0013] In one embodiment, the heating temperature is 600-700° C., and the impregnation pressure is 0.01-10 MPa.

[0014] On the other hand, the present invention provides an intrinsic graphene-reinforced magnesium-based composite material prepared by the above-mentioned method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of the graphene / magnesium composite material, comprising a magnesium alloy matrix and intrinsic graphene with a three-dimensional network structure constructed in the magnesium alloy matrix, and a multi-dimensional nanocarbon-nanocopper heterogeneous interface is constructed between the intrinsic graphene and the magnesium alloy matrix.

[0015] In one embodiment, the electromagnetic shielding effectiveness in the 8.2-12.4 GHz band can reach 60-90 dB, and the thermal conductivity can reach 55-75 W / (m K).

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes a method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of graphene / magnesium composites, which is used to construct an intrinsic graphene preform with a three-dimensional network structure in a magnesium alloy matrix, and to construct a multi-dimensional nanocarbon-nanocopper heterogeneous interface between the intrinsic graphene and the magnesium alloy matrix. The method firstly achieves the purpose of increasing the surface roughness of intrinsic graphene, increasing the contact area, increasing the surface oxygen-containing functional groups, and increasing the compressive strength of the intrinsic graphene preform by in-situ grafting of 1D / 2D nanocarbon; secondly, a micro-capacitance effect is formed by in-situ grafting of 0D / 1D nano-copper, thereby improving the wettability between the intrinsic graphene and the magnesium alloy; then, by regulating the in-situ grafting process, a tight chemical bond can be formed between the multi-dimensional nano-carbon and the nano-copper; finally, an intrinsic graphene-reinforced magnesium-based composite material is prepared by a liquid-solid infiltration and extrusion method, and a nano-carbon-copper heterogeneous interface is constructed. During the preparation process of the intrinsic graphene-reinforced magnesium-based composite material, the nano-copper and the trace elements in the magnesium alloy matrix will chemically react and generate intermetallic compounds Al2CuMg and MgO at the interface, forming a tight chemical coupling at the interface, which can effectively improve the interface bonding and reduce the interface thermal resistance, realize efficient electrical and thermal transmission at the interface, and achieve the effect of synergistically enhancing the electromagnetic shielding and thermal conductivity of the intrinsic graphene-reinforced magnesium-based composite material. The present invention overcomes the problem that traditional magnesium-based composite materials are only regulated for a single performance of electromagnetic shielding or thermal conductivity, overcomes the difficult problems of poor interface wettability and poor interface bonding between graphene and magnesium alloy, and prepares a multi-dimensional nano-carbon-nano-copper heterogeneous interface. By adjusting the type and proportion of the in-situ grafted carbon source, adjusting the heat treatment insulation temperature and time of the in-situ grafted nano-copper, multi-dimensional nano-carbon and nano-copper are in-situ grafted on the surface of the intrinsic graphene substrate. This intrinsic graphene preform is used as a reinforcement for the magnesium-based composite material, and the three-dimensional interconnected structure of the intrinsic graphene in the magnesium-based composite material prepared by the liquid-solid infiltration extrusion method is still retained. Since the raw material used in the preparation of the preform of the present invention is intrinsic graphene, and the intrinsic graphene has a low degree of defects and fewer oxygen-containing functional groups, the preform has a low compressive strength and is difficult to form a tight bond with the multi-dimensional nano-carbon-nano-copper. The difference in shape and dimension between nano-carbon and nano-copper makes the two bond poor.In order to overcome the above-mentioned problems of intrinsic graphene, the present invention brings some oxygen-containing functional groups to the surface of intrinsic graphene by adding a surfactant and a foaming agent; the regulation of the type and proportion of oxygen-containing carbon sources helps to etch the intrinsic graphene substrate and bring rich oxygen-containing functional groups; the grafting of nanocarbon can increase the surface roughness, contact area and number of oxygen-containing functional groups of the intrinsic graphene, which is conducive to its bonding with nano-copper; the oxygen-containing functional groups on the surface of the nanocarbon combine with the anions in the copper-containing oxidant to form chemical bonds, so that chemical bonding is formed between the nanocarbon and the nano-copper; during the preparation of the composite material, the nano-copper and the trace elements in the magnesium alloy matrix will undergo a chemical reaction and generate intermetallic compounds Al2CuMg and MgO at the interface, forming a tight nano-interface layer-magnesium alloy chemical coupling at the interface. The deposition of multidimensional nanocarbon effectively increases the compressive strength of intrinsic graphene, achieving a compressive stress of 50–300 kPa at a compressive strain of 50%. The grafting of multidimensional nanocopper effectively improves the interfacial wettability of intrinsic graphene and the magnesium alloy substrate, reducing the interfacial contact angle from 128° to 78°. In summary, this invention effectively addresses the challenges of poor bonding between intrinsic graphene and the nanointerface layer, between nanocarbon and nanocopper, and between the nanointerface layer and the magnesium alloy.

[0017] Another aspect of the present invention provides an intrinsic graphene-reinforced magnesium-based composite material prepared by the above method, which utilizes a strategy of maintaining the three-dimensional interconnected structure of intrinsic graphene in the magnesium alloy matrix and constructing a multi-dimensional heterogeneous interface layer at the interface between the intrinsic graphene and the magnesium alloy. On the one hand, the construction of the three-dimensional interconnected network structure provides multiple propagation paths for electromagnetic wave transmission, enhancing multiple reflections and scattering; constructing an intrinsic graphene-nanocarbon-nanocopper-magnesium alloy heterogeneous interface structure in the composite material, improving the interface polarization, and generating defect dipole polarization, thereby improving the electromagnetic shielding performance of the composite material. On the other hand, the three-dimensional interconnected network structure provides a channel for heat transfer, effectively reducing the scattering effect of electrons and phonons, and the trace elements in the nanocopper and magnesium alloy react to form intermetallic compounds Al2CuMg and MgO at the interface, effectively reducing the interfacial thermal resistance and improving the thermal conductivity of the composite material.

[0018] The electromagnetic shielding effectiveness of the magnesium-based composite material in the 8.2-12.4 GHz band can reach 60-90 dB, and the thermal conductivity can reach 55-75 W / (m K), which can achieve the synergistic optimization of electromagnetic shielding and thermal conductivity of intrinsic graphene-reinforced magnesium-based composites. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A process flow chart of a method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite provided by the present invention; Figure 2These are scanning electron microscope images of the intrinsic graphene-multidimensional nanocarbon-nanocopper preforms prepared in Examples 4 and 7 of the present invention. DETAILED DESCRIPTION

[0020] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0022] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values within the range (including integers and fractions).

[0023] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0024] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0025] The present invention provides a method for constructing a nano-carbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite material and a composite material based thereon, and constructs an intrinsic graphene preform of a three-dimensional network structure in a magnesium alloy matrix. During the research process, the inventors found that the Raman defect level of intrinsic graphene is low, the surface oxygen-containing functional groups are few, and the compressive strength is low, and the combination with the multidimensional nano-interface layer is difficult. In addition, there are large differences in the shape and dimension of nano-carbon and nano-copper. Ensuring that the two are tightly coupled and playing a role in heterogeneous interface connectivity is the key to synergistically optimizing the electromagnetic shielding and thermal conductivity of intrinsic graphene-enhanced magnesium-based composite materials. Therefore, a multidimensional nano-carbon-nano-copper heterogeneous interface is constructed between intrinsic graphene and a magnesium alloy matrix.

[0026] The aforementioned method for constructing a nanocarbon-copper heterojunction interface to improve the electromagnetic shielding and thermal conductivity of graphene / magnesium composites has the following advantages: on the one hand, the construction of a three-dimensional interconnected network of intrinsic graphene preforms ensures the continuous and efficient conduction of electrons and heat along this pathway. On the other hand, the constructed multi-dimensional nanocarbon-nanocopper heterojunction effectively improves the wettability and interfacial bonding of the composite material, ensuring stable and efficient electrical and thermal transmission at the interface, thereby achieving the goal of synergistically optimizing electromagnetic shielding and thermal conductivity.

[0027] like Figure 1 As shown, the above-mentioned method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite material specifically includes the following steps: 1) Taking the raw material intrinsic graphene, mixing it with a surfactant and a foaming agent, then adding solvent water thereto, performing ultrasonic dispersion treatment to obtain a solution, and freeze-drying to obtain an intrinsic graphene preform.

[0028] The surfactant is one or more of sodium carboxymethyl cellulose, riboflavin sodium phosphate, and polyvinyl pyrrolidone; the foaming agent is sodium bicarbonate or sodium lauryl sulfate; the mass ratio of the surfactant, intrinsic graphene, and foaming agent is 1:(15-30):(30-250); and the concentration of intrinsic graphene in the solution is 5-20 mg / mL.

[0029] Because intrinsic graphene sheets have strong van der Waals interactions, the addition of a foaming agent prevents agglomeration between them. The formation of bubbles helps the graphene preform form a three-dimensional network structure. The addition of surfactants and foaming agents also introduces oxygen-containing functional groups to the surface of the intrinsic graphene sheets, facilitating the subsequent bonding of the intrinsic graphene with the multidimensional nanocarbon-nanocopper composite.

[0030] The sheet size of intrinsic graphene is 3~10 μm, the thickness is 0.8~2.5 nm, and the Raman defect level I D / I G The value is 0.1~0.4, the ultrasonic power is 40~200 W, the ultrasonic time is 60~180 min, the freezing temperature is -50~-10 ℃, the freezing time is 12~48 h, and the drying time is 24~72 h.

[0031] 2) placing the intrinsic graphene preform prepared in step 1) into a chemical vapor deposition furnace, in situ depositing one or more of 1D and 2D nanocarbons on the surface of the intrinsic graphene substrate, and obtaining an intrinsic graphene-nanocarbon preform.

[0032] The chemical vapor deposition process parameters are as follows: the oxygen-containing carbon source is one or more of methanol, ethanol, and propanol, the oxygen-free carbon source is one or more of methane, ethylene, propylene, and acetylene, the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is (1-20):1, the chemical vapor deposition temperature is 850-1500°C, and the chemical vapor deposition time is 1-20 hours.

[0033] The oxygen element in the oxygen-containing carbon source can etch the intrinsic graphene substrate and bring it rich oxygen-containing functional groups, which is conducive to the effective combination between intrinsic graphene and multidimensional nanocarbon. By controlling the proportion of the oxygen-containing carbon source, the Raman defect level of the in-situ grafted nanocarbon can be adjusted. I D / I G The value ranges from 1.1 to 1.6. The significant difference in the degree of graphitization between intrinsic graphene and nanocarbons helps enhance interfacial polarization and facilitates electromagnetic wave dissipation at the interface. By manipulating the type and ratio of the carbon source and the chemical vapor deposition temperature, in situ deposition of one or more of 1D and 2D nanocarbons can be achieved. 1D nanocarbons can form a honeycomb network structure on the surface of intrinsic graphene, while 2D nanocarbons can crosslink intrinsic graphene sheets. In situ grafting of nanocarbons can increase the surface roughness, contact area, and number of oxygen-containing functional groups on the intrinsic graphene surface.

[0034] 3) adding a copper-containing oxidizing agent and a reducing agent to ethanol and ultrasonically treating the ethanol solution to obtain an ethanol solution, placing the intrinsic graphene-nanocarbon preform obtained in step 2) into the ethanol solution, and placing the beaker containing the solution in a vacuum drying oven for static treatment, and then taking out the intrinsic graphene-nanocarbon preform and placing it in air at room temperature to dry.

[0035] The copper-containing oxidant is copper nitrate dihydrate or copper chloride dihydrate, and the reducing agent is one or more of hydrazine hydrate and hexadecylamine. The concentration of the copper-containing oxidant is 0.05 to 0.50 mol / L, the concentration of the reducing agent is 0.01 to 0.50 g / mL, the ultrasonic power is 100 to 500 W, and the ultrasonic time is 10 to 30 minutes. The vacuum degree of the vacuum drying oven is 1 to 50 Pa, the standing time is 6 to 24 hours, and the drying time is 24 to 48 hours.

[0036] The copper-containing oxidant is added to increase the metal source. Placing the beaker containing the ethanol solution in a vacuum drying oven ensures that the intrinsic graphene-nanocarbon preform is fully immersed in the ethanol solution containing the oxidant and reducing agent, ensuring uniform distribution of the solution solute within the preform. Oxygen-containing functional groups on the surface of the nanocarbon-grafted intrinsic graphene combine with anions in the copper-containing oxidant to form chemical bonds, resulting in chemical bonding between the nanocarbon and nanocopper.

[0037] 4) placing the preform prepared in step 3) in a heat treatment furnace for heat treatment to obtain an intrinsic graphene-multidimensional nanocarbon-nanocopper preform.

[0038] The heat treatment process is as follows: Argon is introduced into the heat treatment furnace while the temperature is raised until the holding temperature is reached, and then a hydrogen-argon mixture is introduced into the heat treatment furnace for holding. After the holding temperature is completed, the introduction of the hydrogen-argon mixture is stopped, and only argon is introduced into the heat treatment furnace while the temperature is lowered; The holding temperature is 100~650 ℃, and the holding time is 0.5~3 h; the flow ratio of hydrogen and argon in the hydrogen-argon mixture is 1:(8~30).

[0039] By adjusting the heat treatment temperature and time to control the shape and growth mode of nano-copper, in-situ grafting of one or more of 0D and 1D nano-copper can be achieved.

[0040] 5) The intrinsic graphene-multidimensional nanocarbon-nanocopper preform prepared in step 4) is placed in a concave die extrusion cylinder, and a magnesium alloy substrate is placed on top of the intrinsic graphene-multidimensional nanocarbon-nanocopper preform. The preform is heated under argon protection, and a hydraulic press is started to drive the punch to perform liquid-solid infiltration extrusion on the composite material to obtain an intrinsic graphene-reinforced magnesium-based composite material.

[0041] The heating temperature is 600-700° C., and the infiltration pressure is 0.01-10 MPa.

[0042] At this infiltration temperature and infiltration pressure, the trace elements in the nano-copper and magnesium alloy matrix will undergo chemical reactions and generate intermetallic compounds Al2CuMg and MgO at the interface, forming a tight chemical coupling of the nano-interface layer and the magnesium alloy matrix, which can effectively improve the interface bonding and reduce the interface thermal resistance, and realize efficient electrical and thermal transmission at the interface.

[0043] The present invention provides a method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite. The method comprises the following steps: controlling the type and proportion of the carbon source of in-situ grafted nanocarbon to regulate the shape and defect level of the nanocarbon; controlling the temperature and time of nanocopper heat treatment to control the shape and growth mode of the nanocopper; and then adopting a liquid-solid infiltration and extrusion method to prepare an intrinsic graphene-reinforced magnesium-based composite material, constructing a nanocarbon-copper heterogeneous interface, and improving the electromagnetic shielding and thermal conductivity of the graphene / magnesium composite.

[0044] The intrinsic graphene-reinforced magnesium-based composite material prepared by the above-mentioned preparation method comprises a magnesium alloy matrix and intrinsic graphene with a three-dimensional network structure constructed in the magnesium alloy matrix, and a multi-dimensional nanocarbon-copper heterogeneous interface is constructed between the intrinsic graphene and the magnesium alloy matrix. The electromagnetic shielding effectiveness of the composite material in the 8.2-12.4 GHz band can reach 60-90 dB, and the thermal conductivity can reach 55-75 W / (m K), which can achieve synergistic enhancement of the electromagnetic shielding and thermal conductivity of intrinsic graphene-reinforced magnesium-based composites.

[0045] The principle of the method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite provided by the present invention is as follows: Constructing a three-dimensional intrinsic graphene network within a magnesium alloy matrix maximizes the continuous and efficient conduction of electrons and heat along the network structure, reducing the probability of electron and phonon scattering. A multidimensional nanocarbon-copper heterointerface is constructed between the intrinsic graphene and the magnesium alloy, improving the composite's interfacial wettability and bonding, maximizing the efficient transfer of electrons and heat along the interface. The nanocopper creates a microcapacitor effect, and the heterointerface construction enhances multiple reflection losses, interfacial polarization, and dipole polarization at the interface, contributing to electromagnetic wave dissipation.

[0046] However, intrinsic graphene has the characteristics of low defect levels, few oxygen-containing functional groups, and hydrophobicity. However, the preform has low compressive strength and poor interfacial wettability and bonding with the magnesium alloy matrix. Therefore, the intrinsic graphene preform prepared by the present invention differs from existing methods for preparing graphene oxide preforms, breaking with conventional thinking. The intrinsic graphene preform is obtained by ultrasonically treating intrinsic graphene powder with a surfactant and a foaming agent, followed by freeze-drying. The addition of the surfactant and foaming agent is to introduce some oxygen-containing functional groups to the intrinsic graphene surface, while the addition of the foaming agent is to address the problem of easy agglomeration of intrinsic graphene, thereby forming a three-dimensional network structure in the intrinsic graphene preform. The intrinsic graphene preform is then placed in a chemical vapor deposition furnace, where 1D / 2D nanocarbon is in situ grafted onto the intrinsic graphene substrate. The nanocarbon morphology and content are regulated by controlling the type, ratio, deposition temperature, and deposition time of the carbon source. This etches the intrinsic graphene substrate and enriches it with oxygen-containing functional groups, increasing the intrinsic graphene surface roughness, contact area, and number of oxygen-containing functional groups. This facilitates effective bonding between the intrinsic graphene and the nanointerface layer, and between the nanocarbon and nanocopper. The preform is then placed in an ethanol solution containing a copper-containing oxidant and a reducing agent, and the beaker containing this solution is placed in a vacuum drying oven for vacuum immersion. The vacuum immersion process ensures that the preform is fully immersed in the ethanol solution and that the solute distribution in the solution is uniform. The oxygen-containing functional groups on the surface of the intrinsic graphene grafted with nanocarbon combine with the anions in the copper-containing oxidant to form chemical bonds, resulting in chemical bonding between the nanocarbon and nanocopper. The preform is then placed in a heat treatment furnace for heating. The morphology of the nanocopper is controlled by controlling the holding temperature and time, and 0D / 1D nanocopper is deposited on the surface of the intrinsic graphene-nanocarbon preform. Finally, a liquid-solid infiltration and extrusion method is used to prepare an intrinsic graphene-reinforced magnesium-based composite. The nanocopper and trace elements in the magnesium alloy matrix react chemically to form intermetallic compounds Al2CuMg and MgO at the interface, forming a tight nanointerface layer-magnesium alloy chemical coupling. This effectively improves interfacial bonding and reduces interfacial thermal resistance, enabling efficient electrical and thermal transfer at the interface. In-situ grafting of nanocarbon improves the compressive strength of the intrinsic graphene preform, while in-situ grafting of nanocopper improves the interfacial wettability between the intrinsic graphene and the magnesium alloy matrix.

[0047] In summary, the present invention can effectively improve the problems of poor wettability and poor interface bonding between intrinsic graphene and magnesium alloy, and synergistically enhance the electromagnetic shielding and thermal conductivity of intrinsic graphene-reinforced magnesium-based composite materials.

[0048] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0049] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0050] Example 1 On one hand, this embodiment provides a method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite. The specific steps are as follows: Step 1: Intrinsic graphene, sodium carboxymethyl cellulose, and sodium bicarbonate powders were mixed. Water was added to the mixture in a mass ratio of 1:15:30 (sodium carboxymethyl cellulose: intrinsic graphene: sodium bicarbonate). Ultrasonication was performed at 40 W for 60 minutes to obtain a solution with a concentration of 5 mg / mL of intrinsic graphene. The intrinsic graphene preform was freeze-dried at -10°C for 12 hours and then dried for 24 hours.

[0051] Step 2: The intrinsic graphene preform is placed in a chemical vapor deposition furnace, the oxygen-containing carbon source is methanol, the oxygen-free carbon source is methane, the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is 1:1, the deposition temperature is 850 ° C, and the deposition time is 1 h. 1D nanocarbon can be in situ deposited on the intrinsic graphene substrate to obtain an intrinsic graphene-nanocarbon preform; Step 3: Add 0.05 mol / L copper nitrate dihydrate and 0.01 g / mL hydrazine hydrate to ethanol and ultrasonicate at 100 W for 10 min to prepare an ethanol solution. Place the intrinsic graphene-nanocarbon preform in this ethanol solution and place the beaker containing the solution in a vacuum drying oven at a vacuum level of 1 Pa for 6 h. Then remove the preform and dry it in air at room temperature for 24 h. Step 4: placing the preform in a heat treatment furnace for heat treatment, introducing only argon into the heat treatment furnace during the heating process, introducing a hydrogen-argon mixture into the heat treatment furnace during the holding process, with a flow ratio of hydrogen to argon of 1:8, a holding temperature of 100°C, and a holding time of 0.5 h. During the cooling process, the introduction of the hydrogen-argon mixture was stopped, and only argon was introduced into the heat treatment furnace, and 1D nanocopper was in situ grafted on the surface of the preform to obtain an intrinsic graphene-multidimensional nanocarbon-nanocopper preform; Step 5: Place the intrinsic graphene-multidimensional nanocarbon-nanocopper preform into the die extrusion cylinder, place the magnesium alloy matrix on top of the intrinsic graphene-multidimensional nanocarbon-nanocopper preform, heat it to 600°C under argon protection, start the hydraulic press to drive the punch to perform liquid-solid infiltration extrusion on the composite material, and the infiltration pressure is 0.01 MPa to finally prepare the intrinsic graphene reinforced magnesium-based composite material.

[0052] On the other hand, this embodiment provides an intrinsic graphene reinforced magnesium-based composite material prepared by the above method, which has an electromagnetic shielding effectiveness of about 60 dB in the X-band and a thermal conductivity of about 55 W / (m K).

[0053] Example 2 The difference from Example 1 is that the chemical vapor deposition process parameters in step 2 are: the oxygen-containing carbon source is methanol and ethanol, the oxygen-free carbon source is methane and ethylene, the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is 10:1, the deposition temperature is 1050°C, and the deposition time is 10 h. 1D and 2D interwoven nanocarbons can be in situ deposited on the intrinsic graphene substrate, and an intrinsic graphene-nanocarbon preform is obtained; in step 5, the heating temperature is 650°C, the infiltration pressure is 5 MPa, and the prepared intrinsic graphene reinforced magnesium-based composite material has an electromagnetic shielding effectiveness of approximately 70 dB in the X-band and a thermal conductivity of approximately 60 W / (m K).

[0054] Example 3 The difference from Example 1 is that the chemical vapor deposition process parameters in step 2 are: the oxygen-containing carbon source is propanol, the oxygen-free carbon source is propylene, the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is 20:1, the deposition temperature is 1500 ° C, and the deposition time is 20 h. 2D carbon nanosheets can be in situ deposited on the intrinsic graphene substrate, and an intrinsic graphene-nanocarbon preform is obtained; in step 5, the heating temperature is 700 ° C, the infiltration pressure is 10 MPa, and the prepared intrinsic graphene reinforced magnesium-based composite material has an electromagnetic shielding effectiveness of approximately 75 dB in the X-band and a thermal conductivity of approximately 65 W / (m K).

[0055] Example 4 The difference from Example 1 is that in step 4, only argon is introduced into the heat treatment furnace during the heat treatment heating process, and a hydrogen-argon mixture is introduced into the heat treatment furnace during the insulation process. The flow ratio of hydrogen and argon is 1:20, the insulation temperature is 650 ° C, and the insulation time is 3 h. The hydrogen-argon mixture is stopped during the cooling process, and only argon is introduced into the heat treatment furnace. 0D nano-copper is in situ grafted on the surface of the preform to obtain an intrinsic graphene-multidimensional nano-carbon-nano-copper preform; in step 5, the heating temperature is 650 ° C, the infiltration pressure is 5 MPa, and the prepared intrinsic graphene reinforced magnesium-based composite material has an electromagnetic shielding effectiveness of about 72 dB in the X-band and a thermal conductivity of about 70 W / (m K).

[0056] Example 5 The present invention provides a method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite, and the specific steps are as follows: Step 1: Intrinsic graphene, riboflavin sodium phosphate, and sodium dodecyl sulfate were mixed in a mass ratio of riboflavin sodium phosphate: intrinsic graphene: sodium dodecyl sulfate of 1:22:140. Water was added to the mixed powder and ultrasonicated at 120 W for 120 minutes to obtain a solution with a concentration of 12.5 mg / mL of intrinsic graphene. The intrinsic graphene preform was freeze-dried at -30°C for 30 hours and then dried for 48 hours to prepare it.

[0057] Step 2: The intrinsic graphene preform is placed in a chemical vapor deposition furnace. The oxygen-containing carbon source is propanol, the oxygen-free carbon source is acetylene, the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is 20:1, the deposition temperature is 1500 ° C, and the deposition time is 20 h. 2D carbon nanosheets can be in situ deposited on the intrinsic graphene substrate to obtain an intrinsic graphene-nanocarbon preform; Step 3: Add 0.28 mol / L copper chloride dihydrate and 0.25 g / mL hexadecylamine to ethanol and ultrasonicate at 300 W for 20 min to prepare an ethanol solution. Place the intrinsic graphene-nanocarbon preform in this ethanol solution and place the beaker containing the solution in a vacuum drying oven at 25 Pa for 15 h. Then remove the preform and dry it in air at room temperature for 36 h. Step 4: The preform is placed in a heat treatment furnace for heat treatment. During the heating process, only argon gas is introduced into the heat treatment furnace. During the holding process, a hydrogen-argon mixture is introduced into the heat treatment furnace. The flow ratio of hydrogen and argon is 1:19. The holding temperature is 380°C and the holding time is 1.8 h. During the cooling process, the hydrogen-argon mixture is stopped and only argon gas is introduced into the heat treatment furnace. 0D and 1D interwoven nanocopper are in situ grafted on the surface of the preform to obtain an intrinsic graphene-multidimensional nanocarbon-nanocopper preform. Step 5: Place the intrinsic graphene-multidimensional nanocarbon-nanocopper preform into the die extrusion cylinder, place the magnesium alloy matrix on top of the intrinsic graphene-multidimensional nanocarbon-nanocopper preform, heat it to 650°C under argon protection, start the hydraulic press to drive the punch to perform liquid-solid infiltration extrusion on the composite material, and the infiltration pressure is 5 MPa to finally prepare the intrinsic graphene reinforced magnesium-based composite material.

[0058] On the other hand, this embodiment provides an intrinsic graphene reinforced magnesium-based composite material prepared by the above method, which has an electromagnetic shielding effectiveness of about 80 dB in the X-band and a thermal conductivity of about 68 W / (m K).

[0059] Example 6 The difference from Example 5 is that in step 4, only argon is introduced into the heat treatment furnace during the heating process, and a hydrogen-argon mixture is introduced into the heat treatment furnace during the insulation process. The flow ratio of hydrogen and argon is 1:30, the insulation temperature is 650 ° C, and the insulation time is 3 h. The hydrogen-argon mixture is stopped during the cooling process, and only argon is introduced into the heat treatment furnace. 0D nano-copper is in situ grafted on the surface of the preform, and an intrinsic graphene-multidimensional nano-carbon-nano-copper preform is finally prepared. The intrinsic graphene-enhanced magnesium-based composite material prepared in step 5 has an electromagnetic shielding effectiveness of approximately 80 dB in the X-band and a thermal conductivity of approximately 72 W / (m K).

[0060] Example 7 The difference from Example 5 is that in step 4, only argon is introduced into the heat treatment furnace during the heating process, and a hydrogen-argon mixture is introduced into the heat treatment furnace during the insulation process. The flow ratio of hydrogen and argon is 1:8, the insulation temperature is 100 ° C, and the insulation time is 0.5 h. The hydrogen-argon mixture is stopped during the cooling process, and only argon is introduced into the heat treatment furnace. 1D nanocopper is in situ grafted on the surface of the preform, and an intrinsic graphene-multidimensional nanocarbon-nanocopper preform is finally prepared. The intrinsic graphene-enhanced magnesium-based composite material prepared in step 5 has an electromagnetic shielding effectiveness of approximately 65 dB in the X-band and a thermal conductivity of approximately 60 W / (m K).

[0061] Example 8 On one hand, this embodiment provides a method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite. The specific steps are as follows: Step 1: Intrinsic graphene, polyvinyl pyrrolidone, and sodium lauryl sulfate powders were mixed. Water was added to the mixed powders in a mass ratio of 1:30:250 (polyvinyl pyrrolidone: intrinsic graphene). Ultrasonication was performed at 200 W for 180 minutes to obtain a solution with a concentration of 20 mg / mL of intrinsic graphene. The resulting preform was freeze-dried at -50°C for 48 hours and then dried for 72 hours to produce an intrinsic graphene preform.

[0062] Step 2: The intrinsic graphene preform is placed in a chemical vapor deposition furnace. The oxygen-containing carbon sources are methanol and ethanol, the oxygen-free carbon sources are methane and ethylene, the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is 10:1, the deposition temperature is 1050 ° C, and the deposition time is 10 h. 1D and 2D interwoven nanocarbons can be in situ deposited on the intrinsic graphene substrate to obtain an intrinsic graphene-nanocarbon preform; Step 3: Add 0.50 mol / L copper chloride dihydrate and 0.50 g / mL hexadecylamine to ethanol and ultrasonicate at 500 W for 30 min to prepare an ethanol solution. Place the intrinsic graphene-nanocarbon preform in this ethanol solution and place the beaker containing this solution in a vacuum drying oven at a vacuum level of 50 Pa for 24 h. Then remove the preform and place it in air at room temperature to dry for 48 h. Step 4: The preform is placed in a heat treatment furnace for heat treatment. During the heating process, only argon gas is introduced into the heat treatment furnace. During the holding process, a hydrogen-argon mixture is introduced into the heat treatment furnace. The flow ratio of hydrogen and argon is 1:19. The holding temperature is 380°C and the holding time is 1.8 h. During the cooling process, the hydrogen-argon mixture is stopped and only argon gas is introduced into the heat treatment furnace. 0D and 1D interwoven nanocopper are in situ grafted on the surface of the preform to obtain an intrinsic graphene-multidimensional nanocarbon-nanocopper preform. Step 5: Place the intrinsic graphene-multidimensional nanocarbon-nanocopper preform into the die extrusion cylinder, place the magnesium alloy matrix on top of the intrinsic graphene-multidimensional nanocarbon-nanocopper preform, heat it to 650°C under argon protection, start the hydraulic press to drive the punch to perform liquid-solid infiltration extrusion on the composite material, and the infiltration pressure is 5 MPa to finally prepare the intrinsic graphene reinforced magnesium-based composite material.

[0063] On the other hand, this embodiment provides an intrinsic graphene reinforced magnesium-based composite material prepared by the above method, which has an electromagnetic shielding effectiveness of about 90 dB in the X-band and a thermal conductivity of about 75 W / (m K).

[0064] like Figure 2 As shown, in Example 4, 1D nanocarbon and 0D nanocopper are in situ deposited on the surface of the intrinsic graphene substrate, and in Example 7, 2D nanocarbon and 1D nanocopper are in situ deposited on the surface of the intrinsic graphene substrate. After the intrinsic in situ deposition, the intrinsic graphene-multidimensional nanocarbon-nanocopper preform still maintains a three-dimensional network structure.

[0065] In summary, the present invention proposes a method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of graphene / magnesium composites. An intrinsic graphene preform with a three-dimensional network structure is constructed in a magnesium alloy matrix. Electrons and heat flow can be efficiently transmitted along the three-dimensional connected network structure, and a multi-dimensional nanocarbon-nanocopper heterogeneous interface is constructed. This can solve the problem that the current magnesium-based composite materials only regulate a single performance (electromagnetic shielding or thermal conductivity) (the intrinsic graphene with a three-dimensional network structure cannot have both excellent electromagnetic shielding and thermal conductivity). It further solves the problems of poor wettability and poor interface bonding between graphene and magnesium alloys, weak gelation of intrinsic graphene, and low compressive strength. The problem that the intrinsic graphene cannot withstand the infiltration pressure of the molten magnesium alloy and easily collapses during the preparation of magnesium-based composites by the liquid-solid infiltration and extrusion method is solved.

[0066] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for constructing a nanocarbon-copper heterogeneous interface to improve the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite, characterized in that: The following steps are involved: The intrinsic graphene, surfactant and foaming agent are mixed, and then solvent water is added for ultrasonic dispersion to obtain a solution, and the solution is freeze-dried to obtain an intrinsic graphene preform; The intrinsic graphene preform is used as a substrate for chemical vapor deposition, and nanocarbon is in situ deposited on the surface of the substrate to obtain an intrinsic graphene-nanocarbon preform; wherein the nanocarbon is one or more of 1D nanocarbon and 2D nanocarbon; A copper-containing oxidizing agent and a reducing agent are added to ethanol and ultrasonically treated to obtain an ethanol solution, an intrinsic graphene-nanocarbon preform is placed in the ethanol solution, and the preform is allowed to stand in a vacuum environment. The intrinsic graphene-nanocarbon preform is then taken out and dried in an air environment at room temperature, and then heat-treated. Nanocopper is in situ grafted onto the surface of the intrinsic graphene-nanocarbon preform to obtain an intrinsic graphene-multidimensional nanocarbon-nanocopper preform; wherein the nanocopper is one or more of 0D nanocopper and 1D nanocopper; and wherein the nanocarbon and nanocopper in the intrinsic graphene-multidimensional nanocarbon-nanocopper preform have different dimensions; The magnesium alloy matrix is heated under argon protection, and liquid-solid infiltration and extrusion are performed on the intrinsic graphene-multidimensional nanocarbon-nanocopper preform to obtain an intrinsic graphene reinforced magnesium-based composite material.

2. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, characterized in that: The surfactant is one or more of sodium carboxymethyl cellulose, riboflavin sodium phosphate, and polyvinyl pyrrolidone; and the foaming agent is sodium bicarbonate or sodium lauryl sulfate.

3. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, characterized in that: The mass ratio of the surfactant, intrinsic graphene and foaming agent is 1: (15-30): (30-250); The concentration of the intrinsic graphene in the solution is 5-20 mg / mL.

4. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, characterized in that: The process parameters of the chemical vapor deposition are as follows: The oxygen-containing carbon source is one or more of methanol, ethanol, and propanol; the oxygen-free carbon source is one or more of methane, ethylene, propylene, and acetylene; the mass ratio of the oxygen-containing carbon source to the oxygen-free carbon source is (1-20):1; The temperature of chemical vapor deposition is 850~1500 ℃, and the time of chemical vapor deposition is 1~20 h.

5. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, wherein: The copper-containing oxidant is copper nitrate dihydrate or copper chloride dihydrate; the reducing agent is one or more of hydrazine hydrate and hexadecylamine; the concentration of the copper-containing oxidant is 0.05-0.50 mol / L; and the concentration of the reducing agent is 0.01-0.50 g / mL.

6. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, wherein: The power of ultrasonic treatment was 100-500 W, and the time of ultrasonic treatment was 10-30 min; The static treatment is carried out in a vacuum drying oven under a vacuum environment. The vacuum degree of the vacuum drying oven is 1~50 Pa, and the static treatment time is 6~24 h. The drying time in room temperature air environment is 24~48 hours.

7. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, characterized in that: The process of the heat treatment is as follows: Argon is introduced into the heat treatment furnace while the temperature is raised until the holding temperature is reached, and then a hydrogen-argon mixture is introduced into the heat treatment furnace for holding. After the holding temperature is completed, the introduction of the hydrogen-argon mixture is stopped, and only argon is introduced into the heat treatment furnace while the temperature is lowered; The holding temperature is 100~650 ℃, and the holding time is 0.5~3 h; the flow ratio of hydrogen and argon in the hydrogen-argon mixture is 1:(8~30).

8. The method for constructing a nanocarbon-copper heterogeneous interface for improving the electromagnetic shielding and thermal conductivity of a graphene / magnesium composite according to claim 1, wherein: The heating temperature is 600-700° C., and the infiltration pressure is 0.01-10 MPa.

9. An intrinsic graphene reinforced magnesium-based composite material prepared by the nanocarbon-copper heterogeneous interface construction method for improving the electromagnetic shielding and thermal conductivity of graphene / magnesium composites according to any one of claims 1 to 8, characterized in that: It includes a magnesium alloy matrix and intrinsic graphene with a three-dimensional network structure constructed in the magnesium alloy matrix, and a multi-dimensional nano-carbon-nano-copper heterogeneous interface is constructed between the intrinsic graphene and the magnesium alloy matrix.

10. The intrinsic graphene reinforced magnesium-based composite material according to claim 9, characterized in that: The electromagnetic shielding effectiveness in the 8.2~12.4GHz band can reach 60~90 dB, and the thermal conductivity can reach 55~75 W / (m K).

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