Graphene aluminum vapor chamber and preparation method thereof

Abstract

The invention relates to the technical field of thermal conductive materials, in particular to a graphene aluminum vapor chamber and a preparation method thereof. The graphene aluminum vapor chamber comprises a graphene layer and an aluminum layer, and the graphene layer and the aluminum layer are connected through heat-conducting glue. The preparation method of the heat-conducting adhesive comprises the following steps: adding a matrix material and a curing agent into an organic solvent, and uniformly stirring and mixing to obtain an adhesive matrix; modifying the heat-conducting filler system to obtain a modified heat-conducting filler system; and adding the modified heat-conducting filler system into the adhesive matrix, and uniformly stirring and mixing to obtain the heat-conducting adhesive. The problems of complex preparation process and high production cost of the graphene aluminum composite material can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal conductive materials, and in particular to a graphene aluminum vapor chamber and a preparation method thereof. Background Art

[0002] As electronic devices continue to develop in the direction of miniaturization, high integration and diversified functions, their assembly density and power density continue to increase, and the heat generated increases dramatically. Traditional heat dissipation materials such as copper and aluminum have high thermal conductivity, but these materials have disadvantages such as poor electrical insulation and poor bonding with electronic products, making it difficult to meet the requirements for efficient heat dissipation, high reliability and lightweight of electronic devices. Although high thermal conductivity carbon-based materials represented by graphene have excellent thermal conductivity, the material itself often has problems such as poor mechanical properties. Therefore, high thermal conductivity composite materials with metal material aluminum as the matrix and carbon-based material graphene as the thermal conductivity enhancer came into being.

[0003] At present, in the relevant technology, the methods for preparing graphene aluminum-based composite materials mainly include powder metallurgy, melt casting, electrochemical deposition, high-pressure torsion and stir friction welding. The traditional processing technology usually needs to be carried out under high temperature and high pressure conditions, and the process flow is complicated. For example, the powder consolidation process in the powder metallurgy method usually requires hot pressing for sintering, and the sintering time is generally long. The densification process also needs to be achieved through operations such as hot rolling and extrusion.

[0004] However, when graphene and aluminum are connected at high temperatures, graphene is easily delaminated due to thermal expansion, and carbon-based materials such as graphene and metals are prone to interfacial reactions at high temperatures, generating brittle and easily hydrolyzed Al 4 C 3 phase, which makes it difficult for the two to form a good connection and easily causes interlayer cracking, which is seriously detrimental to the mechanical and thermal properties of the composite material. Summary of the invention

[0005] The present invention aims to solve the current problem that the interface bonding effect between graphene and aluminum substrate is poor and it is difficult to form a good connection.

[0006] In order to solve the above problems, the present invention provides a graphene aluminum heat sink and a preparation method thereof.

[0007] As a first aspect, the present invention relates to a graphene aluminum vapor chamber, which includes a graphene layer and an aluminum layer, wherein the graphene layer and the aluminum layer are connected by a thermally conductive adhesive.

[0008] Optionally, the number of the graphene layers and the number of the aluminum layers are not less than two respectively, and the graphene layers and the aluminum layers are alternately stacked, and each adjacent graphene layer and aluminum layer are connected by a thermally conductive adhesive.

[0009] Optionally, the method for preparing the thermally conductive adhesive comprises the following steps:

[0010] Adding the base material and the curing agent into the organic solvent, stirring and mixing evenly to obtain a glue base;

[0011] Modifying the thermal conductive filler system to obtain a modified thermal conductive filler system;

[0012] The modified thermally conductive filler system is added into the adhesive matrix, and stirred and mixed evenly to obtain the thermally conductive adhesive.

[0013] Optionally, the curing agent is 2-methylimidazole, and based on the mass of the base material being 100%, the added amount of 2-methylimidazole is 5wt% to 10wt%.

[0014] Optionally, the modification of the thermally conductive filler system includes:

[0015] Add silane coupling agent to the ethanol aqueous solution, stir and mix evenly to obtain a modified solution.

[0016] The modified liquid is added to the dried thermal conductive filler system, and then ultrasonic dispersion and drying are performed in sequence to obtain a modified thermal conductive filler system.

[0017] Optionally, the thermally conductive filler system is formed by compounding a plurality of thermally conductive fillers.

[0018] Optionally, based on 100 wt % of the mass of the thermally conductive filler system, the amount of the silane coupling agent added is 1 wt % to 5 wt %.

[0019] Optionally, based on 100 wt % of the mass of the gum matrix, the added amount of the modified thermally conductive filler system is 50 wt % to 90 wt %.

[0020] In a second aspect, the present invention relates to a method for preparing the above-mentioned graphene aluminum vapor chamber, comprising:

[0021] The thermally conductive adhesive after vacuum degassing is evenly coated on the surface of the graphene layer and the aluminum layer, and then the graphene layer and the aluminum layer are stacked and pressed, and finally heat-insulated and cured in sequence to obtain a graphene aluminum heat spreader.

[0022] Optionally, the graphene layer and the aluminum layer are stacked and pressed at 25 MPa to 50 MPa;

[0023] And / or, after the graphene layer and the aluminum layer are stacked and pressed, they are first kept at 60° C. to 80° C. for 1 h to 2 h, and then cured at 100° C. to 120° C. for 1 h to 2 h.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] In an embodiment of the present invention, the graphene layer and the aluminum layer are directly connected by a thermally conductive adhesive. The thermally conductive adhesive can be wetted and spread on the surface of the aluminum layer and the graphene layer, and has good adhesion. Specifically, the thermally conductive adhesive can penetrate into the gaps on the graphene surface, and remove the air adsorbed on the interface of the aluminum layer and the graphene layer, resulting in a bonding effect, forming a mechanical inlay and a clean surface, generating a reactive surface, and improving the bonding strength. The critical surface tension of the aluminum layer is greater than the surface tension of the thermally conductive adhesive, and the adhesive can be immersed in the pits and gaps on the surface of the aluminum layer to form good wetting, resulting in an adsorption effect. Wetting allows the thermally conductive adhesive to be in close contact with the aluminum layer, and permanent bonding is generated by relying on intermolecular forces (including hydrogen bonds and van der Waals forces), thereby achieving reliable connection between the graphene layer and the aluminum layer at low temperatures, thereby avoiding the problem that the graphene layer and the aluminum layer are prone to interface reactions at high temperatures, affecting the interface bonding effect.

[0026] In addition, the thermally conductive adhesive can also directly form phonon and electron heat conduction paths between the aluminum layer and the graphene layer, providing a path for heat conduction. And the thermally conductive adhesive can fill the tiny gap between the graphene and the aluminum to ensure close contact between the two, thereby reducing thermal resistance and improving heat conduction efficiency. The present invention provides a graphene aluminum heat spreader based on bonding, which greatly improves its thermal conductivity while taking into account mechanical properties. The joint welding rate reaches more than 99%, its interface strength is higher than 10MPa, and the thermal conductivity is greater than 300W / (m·K). The use of thermally conductive adhesive makes the bonding process of the graphene layer and the aluminum layer relatively simple, without the need for complex processes or equipment, which helps to reduce production costs and improve production efficiency, and is in line with the principles of green production and energy-saving production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the graphene aluminum heat sink in Example 1 of the present invention.

[0028] Description of reference numerals:

[0029] 1. Graphene layer; 2. Aluminum layer. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0032] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0033] Methods for connecting dissimilar materials include brazing, diffusion welding, and SPS. However, the following problems are common when using the above processes to connect graphene and aluminum: (1) The interface wettability between aluminum alloy and graphene is poor. The contact angle between graphene and aluminum is about 140°. It is easy to generate holes and defects at the interface between the two. The interface bonding strength is low and the interface thermal resistance is large, making it difficult to connect using brazing. (2) Carbon-based materials such as graphene are prone to interface reactions with metals at high temperatures, generating brittle and easily hydrolyzed Al2O3. 4 C 3 (3) The thermal expansion coefficients of graphene and aluminum are very different, which has a serious adverse effect on the mechanical and thermal properties of the composite material, making it difficult to form a good connection during diffusion welding, and easily causing interlayer cracking. (4) The thermal expansion coefficients of graphene and aluminum are very different, and there is a serious thermal mismatch at the interface. When experiencing thermal cycles or thermal shocks, obvious stress concentration will occur. When the temperature is higher than 200°C, it is very easy to cause interlayer cracking, and the interface bonding reliability is low.

[0034] Therefore, powder metallurgy and melt casting are the most commonly used methods for preparing graphene aluminum-based composites.

[0035] Powder metallurgy generally includes three stages: uniform mixing of graphene and aluminum powder, powder consolidation and densification. Among them, uniform mixing and dispersion of graphene and aluminum powder is the key to the early stage of powder metallurgy. There are several preparation methods, including mechanical ball milling, flake powder metallurgy and in-situ self-generation.

[0036] Mechanical ball milling is a process in which multiple powders are mixed under the grinding action of ball milling media. It mainly achieves powder crushing and dispersion under the collision, impact and shearing action of grinding balls. The flake powder metallurgy method draws on the idea of ​​shell bionics and relies on the electrostatic interaction between graphene oxide and the surface of aluminum powder to disperse graphene. The core idea of ​​the in-situ self-generation method is to reduce carbon-containing organic matter to graphene on the surface of aluminum particles during heating. Generally, copper and nickel metal particles are selected as growth substrates and mixed with aluminum powder. The method of growing graphene on the metal surface can construct a three-dimensional / quasi-three-dimensional network structure of graphene. The biggest advantage of in-situ self-generation of graphene is that it can solve the problem of graphene agglomeration, while generating three-dimensional constraints on the matrix, which has good toughness while strengthening.

[0037] The powder consolidation process mainly includes hot pressing and spark plasma sintering. The heating efficiency of hot pressing is relatively low, and the sintering time is generally longer. Spark plasma sintering directly uses electric current to heat the mold and sintering material. Compared with hot pressing, it has the characteristics of extremely high heating efficiency, fast heating rate, low sintering temperature, and short insulation time, but the machine cost is relatively high.

[0038] The melt casting method generally includes processes such as pressure infiltration, stirring casting and spray deposition. Compared with the powder metallurgy method, it is more difficult to achieve uniform dispersion of graphene in the preparation of composite materials by melt casting, and the preparation of graphene aluminum-based composite materials by melt casting is still in laboratory research. How to improve the dispersion of graphene on an industrial scale to meet the needs of use remains to be solved.

[0039] Based on the problems existing in the above-mentioned related technologies, an embodiment of the present invention provides a graphene aluminum heat sink and a preparation method thereof.

[0040] In a first aspect, the graphene aluminum vapor chamber in the embodiment of the present invention comprises a graphene layer 1 and an aluminum layer 2, and the graphene layer 1 and the aluminum layer 2 are connected by a thermally conductive adhesive.

[0041] In an embodiment of the present invention, the graphene layer 1 and the aluminum layer 2 are directly connected by a thermally conductive adhesive. The thermally conductive adhesive can be wetted and spread on the surface of the aluminum layer 2 and the graphene layer 1, and has good adhesion. Specifically, the thermally conductive adhesive can penetrate into the gaps on the graphene surface, and remove the air adsorbed on the interface of the aluminum layer 2 and the graphene layer 1, resulting in a bonding effect, forming a mechanical inlay and a clean surface, generating a reactive surface, and improving the bonding strength. The critical surface tension of the aluminum layer 2 is greater than the surface tension of the thermally conductive adhesive, and the adhesive can be immersed in the pits and gaps on the surface of the aluminum layer 2 to form good wetting, resulting in an adsorption effect. Wetting makes the thermally conductive adhesive in close contact with the aluminum layer 2, and relies on intermolecular forces (including hydrogen bonds and van der Waals forces) to produce permanent adhesion, thereby achieving reliable connection between the graphene layer 1 and the aluminum layer 2 at low temperatures, thereby avoiding the problem that the graphene layer 1 and the aluminum layer 2 are prone to interface reactions at high temperatures and affect the interface bonding effect.

[0042] In addition, the thermally conductive adhesive can also directly form phonon and electron heat conduction paths between the aluminum layer 2 and the graphene layer 1, providing a path for heat conduction. The thermally conductive adhesive can fill the tiny gap between the graphene and the aluminum to ensure close contact between the two, thereby reducing thermal resistance and improving heat conduction efficiency. The present invention provides a graphene aluminum heat spreader based on bonding, which greatly improves its thermal conductivity while taking into account mechanical properties. The joint welding rate reaches more than 99%, its interface strength is higher than 10MPa, and the thermal conductivity is greater than 300W / (m·K). The use of thermally conductive adhesive makes the bonding process of the graphene layer 1 and the aluminum layer 2 relatively simple, without the need for complex processes or equipment, which helps to reduce production costs and improve production efficiency, and is in line with the principles of green production and energy-saving production.

[0043] Optionally, the number of graphene layers 1 and aluminum layers 2 is not less than two, and the graphene layers 1 and aluminum layers 2 are alternately stacked, and each adjacent graphene layer 1 and aluminum layer 2 is connected by a thermally conductive adhesive.

[0044] Since graphene has good flexibility and bending resistance, and aluminum, as a metal material, has higher mechanical strength, the embodiment of the present invention alternately stacks multiple layers of graphene and aluminum layer 2, which can not only improve the heat dissipation performance and mechanical strength of the heat spreader as a whole, but also make full use of the flexibility of graphene itself, so that the overall flexibility of the heat spreader is better, which can meet the heat dissipation requirements of devices of different shapes and is suitable for a variety of products such as folding screen mobile phones.

[0045] In some optional embodiments, the method for preparing the thermally conductive adhesive of the present invention may include the following steps:

[0046] S1: Adding base material and curing agent into an organic solvent, stirring and mixing evenly to obtain a glue base.

[0047] The organic solvent may be anhydrous ethanol, and the matrix material may be epoxy resin, polyurethane or silicone colloid. Preferably, the matrix material of the embodiment of the present invention is epoxy resin, such as bisphenol A epoxy, phenolic epoxy and alicyclic epoxy. The curing agent may be 2-methylimidazole.

[0048] Specifically, the glue matrix uses anhydrous ethanol as a solvent, and then epoxy resin colloid and 2-methylimidazole are added in sequence, and the added amount of 2-methylimidazole is 5wt% to 10wt% based on the mass of the matrix material as 100%. After mixing evenly, it is placed in a fume hood for ventilation for 1h to 2h to obtain the glue matrix.

[0049] S2: Modifying the thermal conductive filler system to obtain a modified thermal conductive filler system.

[0050] Specifically, the thermally conductive filler system can be a metal filler such as copper, silver, aluminum, gold, or a metal nitride such as boron nitride or aluminum nitride, or a metal oxide such as aluminum oxide or magnesium oxide, or a non-metallic oxide such as silicon oxide, or a non-metallic carbide such as silicon carbide. Preferably, the thermally conductive filler system can be obtained by compounding a plurality of thermally conductive fillers of different particle sizes and different morphologies according to a specific ratio.

[0051] Furthermore, the thermal conductive filler system can be modified by using a silane coupling agent, and the silane coupling agent can be KH550, KH560 or KH570. Specifically, first, a silane coupling agent is added to an ethanol aqueous solution with a concentration of 70wt% to 95wt%, and the mixture is stirred and mixed to obtain a modified solution. Wherein, based on the mass of the thermal conductive filler system being 100wt%, the amount of the silane coupling agent added is 1wt% to 5wt%. The modified solution is added to the dried thermal conductive filler system, and then ultrasonically dispersed for 15min to 30min to uniformly disperse the silane coupling agent on the surface of the thermal conductive filler. Finally, the mixture is dried at 70°C to 80°C for 1h to 2h to allow the thermal conductive filler to fully react with the silane coupling agent to obtain a modified thermal conductive filler system.

[0052] It should be noted that before adding the modifying liquid, the thermal conductive filler system to be treated should be dried for more than 12 hours to fully remove the moisture or other volatile substances in the filler to ensure the stability and performance of the filler during use.

[0053] S3: adding the modified thermal conductive filler system to the adhesive matrix, stirring and mixing evenly to obtain a thermal conductive adhesive, wherein the amount of the modified thermal conductive filler system added is 50wt% to 90wt% based on the mass of the adhesive matrix being 100wt%.

[0054] The present invention uses a silane coupling agent to modify the surface of the thermally conductive filler, which can effectively improve the interfacial properties between the inorganic filler and the resin matrix and enhance its wettability. According to tests, the thermally conductive adhesive prepared by the above process can reach a strength of 10-15MPa and a thermal conductivity of 1-2W / (m·K), which is conducive to achieving a reliable connection between the graphene layer 1 and the aluminum layer 2.

[0055] In the second aspect, an embodiment of the present invention also provides a method for preparing the above-mentioned graphene aluminum heat spreader, comprising: evenly coating the thermally conductive adhesive after vacuum degassing on the surface of the graphene layer 1 and the aluminum layer 2, then stacking the graphene layer 1 and the aluminum layer 2 and pressing them, and finally successively insulating and curing to obtain the graphene aluminum heat spreader.

[0056] Specifically, the graphene layer 1 and the aluminum layer 2 can be stacked and pressed at 25 MPa to 50 MPa. After the graphene layer 1 and the aluminum layer 2 are stacked and pressed, they can be kept at 60° C. to 80° C. for 1 h to 2 h, and then cured at 100° C. to 120° C. for 1 h to 2 h. A graphene aluminum soaking plate is obtained.

[0057] Furthermore, for a graphene aluminum heat spreader containing multiple layers of graphene layers 1 and aluminum layers 2, thermal conductive adhesive can be evenly coated on the upper and lower surfaces of the graphene layer 1 and the aluminum layer 2 by screen printing, and then the graphene layer 1 and the aluminum layer 2 coated with thermal conductive adhesive are assembled layer by layer in a mold, so that each adjacent graphene layer 1 and aluminum layer 2 are connected by the thermal conductive adhesive.

[0058] The present invention is described in detail below through specific examples and comparative examples:

[0059] Example 1

[0060] (I) Preparation of thermal conductive adhesive

[0061] Preparation of the gum matrix: Add epoxy resin EPIKOTE 828 and 2-methylimidazole to anhydrous ethanol, stir and mix evenly, and place in a fume hood for 2 hours to obtain a gum matrix, wherein the amount of 2-methylimidazole added is 5wt% based on the mass of epoxy resin EPIKOTE 828 being 100wt%.

[0062] Preparation of modified thermally conductive filler system: Aluminum nitride, aluminum oxide, silicon dioxide and silicon carbide are compounded in a ratio of 1:1:1:1 to obtain a thermally conductive filler compound system, and the thermally conductive filler compound system is dried in a drying oven for 15 hours. At the same time, silane coupling agent KH560 is added to a 70wt% ethanol aqueous solution to obtain a modified liquid. The amount of silane coupling agent KH560 added is 1wt% of the thermally conductive filler compound system. The prepared modified liquid is added to the filler system, ultrasonically dispersed for 30 minutes, and finally, dried in a drying oven at 70°C for 2 hours to obtain a modified thermally conductive filler system.

[0063] Preparation of thermal conductive adhesive: Add the modified thermal conductive filler system into the adhesive matrix, stir it thoroughly and evenly to obtain the thermal conductive adhesive. Based on the mass of the adhesive matrix as 100wt%, the addition amount of the modified thermal conductive filler system is 50wt%.

[0064] (II) Preparation of graphene aluminum heat sink

[0065] The above-mentioned thermal conductive adhesive is used to prepare a graphene aluminum-based multilayer heat sink with a size of 10mm×10mm-500mm×500mm. Figure 1As shown, the direction of the arrow in the figure represents the pressing direction. The bottom layer of the graphene aluminum heat spreader in this embodiment is the graphene layer 1, and the top layer is the aluminum layer 2. The number of graphene layers 1 and aluminum layers 2 is 9. The prepared thermal conductive adhesive is defoamed in a vacuum environment, and then the thermal conductive adhesive is evenly coated on the upper and lower surfaces of the graphene layer 1 and the aluminum layer 2 by screen printing, and the graphene layer 1 and the aluminum layer 2 coated with the thermal conductive adhesive are assembled layer by layer in the mold and pressed at 25MPa. Finally, it is placed in a vacuum drying oven, kept at 60°C for 2h, and then continued to cure at 100°C for 1h to obtain a graphene aluminum heat spreader.

[0066] Example 2

[0067] The difference between this embodiment and embodiment 1 is that, in the preparation process of the thermally conductive adhesive, based on the mass of the epoxy resin EPIKOTE828 being 100wt%, the added amount of 2-methylimidazole is 10wt%; based on the mass of the thermally conductive filler system being 100wt%, the added amount of the silane coupling agent KH560 is 5wt% of the thermally conductive filler compound system; based on the mass of the adhesive matrix being 100wt%, the added amount of the modified thermally conductive filler system is 90wt%.

[0068] Comparative Example 1

[0069] In this comparative example, nickel is first plated on the surfaces of the graphene layer and the aluminum layer, respectively, and then the nickel-plated graphene layer and the nickel-plated aluminum layer are welded by soldering to obtain a graphene aluminum soaking plate.

[0070] Comparative Example 2

[0071] In this comparative example, a copper layer is first formed on the surface of an aluminum substrate by electroplating or magnetron sputtering, and then a graphene layer is formed on the copper layer by plasma chemical vapor deposition to obtain a graphene aluminum soaking plate.

[0072] The interface strength and thermal conductivity of the graphene aluminum vapor chamber in Example 1-2 and Comparative Example 1-2 were tested respectively, and the results are shown in Table 1:

[0073] Table 1 Interface strength and thermal conductivity of graphene aluminum heat sink in Example 1-2 and Comparative Example 1-2

[0074]

[0075] As can be seen from Table 1, the thermal conductivity of the graphene aluminum vapor chamber in Example 1 and Example 2 is much higher than that in Comparative Example 1 and Comparative Example 2, and also has a relatively good interface strength. This shows that the graphene aluminum vapor chamber in the embodiment of the present invention has outstanding progress in thermal conductivity, and also has good mechanical properties.

[0076] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A graphene aluminum soaking plate, characterized in that: It comprises a graphene layer (1) and an aluminum layer (2), wherein the graphene layer (1) and the aluminum layer (2) are connected via a heat-conducting adhesive.

2. The graphene aluminum vapor chamber according to claim 1, characterized in that: The number of the graphene layers (1) and the number of the aluminum layers (2) are not less than two, respectively, and the graphene layers (1) and the aluminum layers (2) are alternately stacked, and adjacent graphene layers (1) and aluminum layers (2) are connected via the thermally conductive adhesive.

3. The graphene aluminum vapor chamber according to claim 1, characterized in that: The preparation method of the thermal conductive adhesive comprises the following steps: Adding the base material and the curing agent into the organic solvent, stirring and mixing evenly to obtain a glue base; Modifying the thermal conductive filler system to obtain a modified thermal conductive filler system; The modified thermally conductive filler system is added into the adhesive matrix, and stirred and mixed evenly to obtain the thermally conductive adhesive.

4. The graphene aluminum vapor chamber according to claim 3, characterized in that: The curing agent is 2-methylimidazole. Based on the mass of the base material being 100%, the added amount of 2-methylimidazole is 5wt% to 10wt%.

5. The graphene aluminum vapor chamber according to claim 3, characterized in that: The modification of the thermal conductive filler comprises: Add silane coupling agent to the ethanol aqueous solution, stir and mix evenly to obtain a modified solution. The modified liquid is added to the dried thermal conductive filler system, and then ultrasonic dispersion and drying are performed in sequence to obtain a modified thermal conductive filler system.

6. The graphene aluminum vapor chamber according to claim 5, characterized in that: The thermally conductive filler system is formed by compounding a plurality of thermally conductive fillers.

7. The graphene aluminum vapor chamber according to claim 5, characterized in that: Based on 100 wt % of the mass of the thermal conductive filler system, the added amount of the silane coupling agent is 1 wt % to 5 wt %.

8. The graphene aluminum vapor chamber according to claim 3, characterized in that: Based on 100 wt % of the mass of the gum matrix, the added amount of the modified thermally conductive filler system is 50 wt % to 90 wt %.

9. A method for preparing a graphene aluminum vapor chamber, for preparing the graphene aluminum vapor chamber as claimed in any one of claims 1 to 8, characterized in that: include: The thermally conductive adhesive after vacuum degassing is evenly coated on the surface of the graphene layer (1) and the aluminum layer (2), and then the graphene layer (1) and the aluminum layer (2) are stacked and pressed, and finally heat-insulated and cured in sequence to obtain a graphene aluminum heat spreader.

10. The method for preparing a graphene aluminum vapor chamber according to claim 9, characterized in that: The graphene layer (1) and the aluminum layer (2) are stacked and then pressed at 25 MPa to 50 MPa; And / or, after the graphene layer (1) and the aluminum layer (2) are stacked and pressed, they are first kept at 60° C. to 80° C. for 1 hour to 2 hours, and then cured at 100° C. to 120° C. for 1 hour to 2 hours.

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