Preparation of high thermal conductivity copper-oxidized graphene brick-mud structure composite material

Abstract

The present application relates to the technical field of brick-mud structure composite material, especially to the preparation of copper-oxidized graphene brick-mud structure composite material with high thermal conductivity. The present application aims to solve the problems of uneven dispersion of graphene in copper matrix and poor interface bonding force between graphene and copper, effectively increases the volume fraction of graphene in copper matrix through the composite configuration of brick-mud structure, thereby effectively improves the thermal conductivity of the composite material and reduces the thermal expansion coefficient of the copper matrix; through optimizing the electrophoretic deposition process parameters, a thin and loose oxidized graphene intermediate layer is obtained, and the oxidized graphene is well reduced in the subsequent electrodeposition process, the copper grains densely cover the loose oxidized graphene layer, forming a continuous spatial network structure, thereby enhancing the interface bonding force between copper and oxidized graphene.

Description

Technical Field

[0001] This invention relates to the field of brick-mud composite material technology, and in particular to the preparation of copper-graphene oxide brick-mud composite materials with high thermal conductivity. Background Technology

[0002] With the rapid development of electronic devices towards miniaturization, high power, and high integration, efficient heat dissipation is crucial for maintaining high-performance operation and extending device lifespan. Therefore, developing thermal management materials with high thermal conductivity is of great practical significance. Copper is a material with excellent machinability, thermal conductivity, and electrical conductivity, and is widely used as a thermal conductive material. However, traditional copper cannot meet the rapid development of the current electronic component packaging industry, generating a large amount of heat per unit time and unit volume, which leads to a significant decrease in its performance. Against this backdrop, copper-based composite materials have emerged due to their enhanced thermal conductivity. Carbon materials such as carbon fibers, carbon nanotubes, and graphene have attracted much attention due to their unique high-performance properties. In particular, graphene is a novel two-dimensional nanocarbon material with a hexagonal honeycomb structure, where carbon atoms are arranged in sp... 2 Hybrid interconnections. Due to its excellent electrical and thermal conductivity and low coefficient of thermal expansion, graphene is considered an ideal reinforcing material for manufacturing metal matrix composites. Copper can be combined with graphene to form thermally conductive composite materials. Among them, graphene-reinforced copper-based composites are a good example of thermally managed composite materials.

[0003] A review of existing technical literature revealed that the uneven dispersion of graphene in the copper matrix and the weak bonding strength at the graphene / copper interface are two major obstacles to improving the reinforcement efficiency of graphene-reinforced copper matrix composites. On the one hand, due to the aggregation of graphene in the copper matrix, traditional preparation methods struggle to increase the graphene content in the composite material, thus impairing the reinforcing effect of graphene on the copper matrix. On the other hand, the weak van der Waals forces connecting graphene and the copper matrix at their interface lead to poor interfacial bonding and easy interface separation. Therefore, improving the interfacial bonding between graphene and copper and the reinforcing effect of graphene on the copper matrix are current research priorities.

[0004] Inspired by biological structural materials in nature, biomimetic composites have become a research focus in materials science in recent years. Biomimetic composite configurations mimic the microscopic composite structures of natural biological materials with excellent performance and functional properties, and are applied to the composite process of engineering materials to prepare composite materials with multi-scale, multi-layered biomimetic structures. Currently, biomimetic "brick-and-mortar" composite configurations have become the object of imitation for the superior performance of materials. KMYang et al. published a paper entitled "Anisotropic thermalconductivity and associated heat transport mechanism in roll-to-roll graphene-reinforced copper matrix composites" in *Acta Materialsalia*, Volume 197:342-354, July 9, 2020. They prepared layered graphene-reinforced copper matrix composites using R2R CVD followed by HIP processes, and the composites possessed excellent thermal properties. However, the CVD method has high production conditions and costs, which is not conducive to large-scale industrial production, and the volume fraction of graphene obtained is low, which cannot effectively improve the thermal expansion coefficient of the copper matrix. Therefore, improving the interfacial bonding between graphene and copper and the strengthening effect of graphene on the copper matrix are the focus of current research. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for preparing a copper-graphene oxide brick-and-mortar composite material with high thermal conductivity. This invention utilizes a "brick-and-mortar" composite configuration to prepare a copper-graphene oxide laminated composite material with a layered structure. A thin and porous graphene oxide interlayer is obtained by optimizing electrophoretic deposition process parameters. During subsequent electrodeposition, copper grains densely cover the porous graphene oxide layer, forming a continuous spatial network structure. This enhances the interfacial bonding between copper and graphene oxide, resulting in a copper-graphene oxide brick-and-mortar composite material with high thermal conductivity. This material is applicable to the field of composite material preparation.

[0006] This invention aims to address the problems of uneven graphene dispersion in a copper matrix and poor interfacial bonding between graphene and copper. The invention effectively increases the volume fraction of graphene in the copper matrix through a brick-and-mortar composite configuration, thereby significantly improving the thermal conductivity of the composite material and reducing the coefficient of thermal expansion of the copper matrix. By optimizing the electrophoretic deposition process parameters, a thin and porous graphene oxide interlayer is obtained, and the graphene oxide is well reduced during subsequent electrodeposition. The copper grains densely cover the porous graphene oxide layer, forming a continuous spatial network structure, thus enhancing the interfacial bonding between copper and graphene oxide. The improved thermal conductivity of the composite material is attributed to the partial reduction of graphene oxide and the improved interfacial bonding between copper and graphene oxide during the alternating electrodeposition-electrophoretic deposition process. The copper-graphene oxide brick-and-mortar composite material prepared using this invention exhibits excellent comprehensive performance, providing a viable method for developing thermal management materials with high thermal conductivity.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] This invention provides the preparation of a copper-graphene oxide brick-mud structure composite material with high thermal conductivity, comprising the following steps:

[0009] (1) Copper is deposited on the substrate using an electrodeposition process to obtain an electrodeposited copper substrate;

[0010] (2) Graphene oxide is deposited on the electrodeposited copper substrate prepared in step (1) by electrophoretic deposition process to obtain graphene oxide / copper composite material;

[0011] (3) Copper is deposited on the graphene oxide / copper composite material prepared in step (2) by electrophoretic deposition process to obtain copper / graphene oxide / copper laminate composite material;

[0012] (4) Repeat steps (2) and (3) several times to obtain copper-graphene oxide brick-mud composite material.

[0013] In one embodiment of the present invention, in step (1), during the electrodeposition process, the plating solution is composed of CuSO4·5H2O, concentrated sulfuric acid, and hydrochloric acid; wherein the concentration of CuSO4·5H2O is 220 g / L, the concentrated sulfuric acid is 98% sulfuric acid by mass, and the concentration of hydrochloric acid is 20-40 mg / L.

[0014] In one embodiment of the present invention, the mass ratio of CuSO4·5H2O, concentrated sulfuric acid and hydrochloric acid is 55:16:14.

[0015] In one embodiment of the present invention, the pH of the plating solution is 1.

[0016] In one embodiment of the present invention, the substrate is placed in a plating solution and electrodeposition is performed using a dual-electrode electrodeposition method;

[0017] The anode is a pure copper plate with a purity of 99.9% (4.5cm×5cm×0.2mm), and the cathode is a graphite sheet (3cm×5cm×1mm).

[0018] In one embodiment of the present invention, the current density during electrodeposition is 3–12 A / dm³. 2 The electrodeposition time is 15–25 min;

[0019] Preferably, the current density is 9 A / dm. 2 .

[0020] In one embodiment of the present invention, the copper plating thickness is approximately 25 μm during the electrodeposition process.

[0021] In one embodiment of the present invention, in step (2), during the electrodeposition process, the plating solution is composed of graphene oxide slurry and PAA500 (polyacrylic acid); wherein the mass fraction of graphene oxide slurry is 1 wt% and the concentration is 0.4 g / L; and the mass fraction of PAA500 is 50 wt%.

[0022] In one embodiment of the present invention, the mass ratio of graphene oxide slurry to PAA500 is 500:1.

[0023] In one embodiment of the present invention, an electrodeposited copper substrate is placed in a plating solution and a dual-electrode electrodeposition is performed.

[0024] The anode is a graphite sheet pre-plated with copper, and the cathode is a pure copper plate (4.5cm×5cm×0.2mm) with a purity of 99.9%.

[0025] In one embodiment of the present invention, during the electrodeposition process, the applied voltage is fixed at 10V and the electrophoresis time is 0-30s;

[0026] Preferably, the electrophoresis time is 15 s.

[0027] This invention reveals that when the graphene oxide layer deposited under optimal electrophoretic deposition process parameters is thin and porous, copper grains densely cover the porous graphene oxide layer during subsequent electrodeposition, effectively improving the composite material's performance. If the electrophoresis time is too short, the graphene oxide loading is insufficient to fully utilize its reinforcing effect. If the electrophoresis time is too long, the loaded graphene oxide layer becomes too dense, leading to graphene oxide agglomeration, reduced composite foil density, and consequently decreased tensile and thermal conductivity. Adjusting the electrophoresis time of the graphene oxide layer can effectively prepare copper / graphene oxide / copper composite materials with excellent overall performance.

[0028] When the number of graphene oxide interlayers is small, the thermal conductivity of the composite material is higher than that of electrodeposited pure copper foil (395.4 W·m). -1 ·k -1 As the number of graphene oxide interlayers increases, the thermal conductivity of the composite foil begins to decrease. The thermal conductivity of composites containing 4 and 5 layers of graphene oxide is lower than that of pure copper foil. The distribution and reduction degree of graphene oxide in the copper matrix, as well as the good interfacial bonding of graphene oxide in the copper matrix, are key factors in improving the thermal conductivity of the composite material. An appropriate graphene oxide content helps to improve the thermal performance of the composite material.

[0029] In one embodiment of the present invention, in step (4), alternating electrodeposition and electrophoretic deposition processes can obtain copper-graphene oxide laminated composite materials with different graphene thicknesses and different stack numbers; during the preparation process of the alternating electrodeposition-electrophoretic deposition method, the partial reduction of graphene oxide and the improvement of the interfacial bonding force between copper and graphene oxide effectively enhance the comprehensive performance of the composite material.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention effectively increases the volume fraction of graphene in a copper matrix through a "brick-and-mortar" laminated composite configuration, thus preparing a copper-graphene oxide laminated composite material. During the composite material preparation process, a thin and porous graphene oxide interlayer is obtained by optimizing the electrophoretic deposition process parameters. In the subsequent electrodeposition process, copper grains densely cover the porous graphene oxide layer, forming a continuous spatial network structure. This enhances the interfacial bonding between copper and graphene oxide, resulting in a copper-graphene oxide brick-and-mortar structured composite material with high thermal conductivity. Attached Figure Description

[0032] Figure 1 The image shows the macroscopic morphology of the pre-electrodeposited pure copper foil in Example 1 and the electrophoretic graphene oxide layer on the surface of the pre-electrodeposited copper foil.

[0033] Figure 2 The images show the microstructure of the pre-electrodeposited pure copper foil and the electrophoretic graphene oxide layer on the surface of the pre-electrodeposited copper foil in Example 1; where (a) & (e) pre-plated copper, (b) & (f) 5s, (c) & (g) 15 seconds, and (d) & (h) 30s;

[0034] Figure 3 The thermal conductivity of the pre-electrodeposited pure copper foil in Example 1 and the composite material of electrophoretically deposited graphene oxide on the surface of the pre-electrodeposited copper foil;

[0035] Figure 4 The thermal conductivity of the composite materials containing different amounts of graphene oxide interlayers in Example 2;

[0036] Figure 5 The microstructure of the copper coatings deposited at different times after electrophoretic deposition of the pre-deposited copper surface graphene oxide layer in Comparative Examples 1-3 is shown. Detailed Implementation

[0037] Unless otherwise specified, all reagents used in the following embodiments are commercially available reagents, and all detection methods and techniques used are conventional detection methods and techniques in the art.

[0038] Example 1

[0039] This embodiment provides a method for preparing a copper / graphene oxide / copper laminate composite material, the specific method of which is as follows:

[0040] (1) A copper plating layer was electrodeposited on the graphite sheet using a DP3020 DC power supply. The plating solution composition was: CuSO4·5H2O 220g / L (55g), concentrated sulfuric acid (98%) 65g / L (16.25g), and hydrochloric acid 30mg / L (14.6g). The pH of the plating solution was 1, the temperature was room temperature (25℃), and ultrasonic treatment was used as an auxiliary process during electrodeposition. A copper plating layer with a thickness of approximately 25μm was uniformly electrodeposited on one side of the graphite sheet using a dual-electrode electrodeposition method, with a current density of 9A / dm³. 2 The corresponding electrodeposition time is 15 min.

[0041] (2) Graphene oxide was electrophoretically deposited on the prepared electrodeposition copper substrate using a DP3020 DC power supply. The plating solution consisted of: graphene oxide slurry (an aqueous solution of graphene oxide) with a concentration of 0.4 g / L and a dosage of 10 g; and PAA500 with a concentration of 0.08 g / L and a dosage of 0.02 g. Electrophoretic deposition times were set to 0 s, 5 s, 10 s, 15 s, 25 s, and 30 s, respectively, to deposit one layer of graphene oxide intermediate layer. The thickness of the composite material was controlled to be 50 μm.

[0042] (3) After electrophoretic deposition of graphene oxide, the electrophoretically deposited copper / graphene oxide composite material is used as the cathode, and copper plating is electrodeposited again on its surface using the same process. The composite layer is then peeled off to obtain copper / graphene oxide / copper laminate composite material.

[0043] The macroscopic morphology of pre-electrodeposited pure copper foil and the 5s, 15s, and 30s electrophoretic graphene oxide layers on the surface of the pre-electrodeposited copper foil were observed, and the microstructure was characterized, such as... Figure 1 and Figure 2 As shown. From Figure 1As can be seen from the macroscopic photographs of the pre-electrodeposited copper layer and the graphene oxide layer electrophoretically deposited on the surface of the pre-electrodeposited copper layer at different times, compared with the smooth and bright surface of the electrodeposited pure copper foil, a layer of graphene oxide was deposited on the surface of the copper foil at different electrophoresis times. With the increase of electrophoresis time (5s, 15s, 30s), the graphene oxide layer on the surface of the copper foil showed a color change from light green to green to brownish-green, and the thickness of the graphene oxide layer increased. From Figure 2 It can be seen that when a shorter electrophoresis time is used, the graphene oxide layer is very thin, and some areas are still exposed cellular copper polycrystalline material, that is, the graphene oxide only covers the surface of the copper foil locally; when a longer electrophoresis time is used, the surface contrast becomes higher, and the thickness of the graphene oxide covering the surface of the copper foil becomes uneven, and the wrinkled layered graphene oxide sheets covering the surface of the copper polycrystalline material can be clearly seen.

[0044] The thermal conductivity of pre-electrodeposited pure copper foil and composite materials with 5s, 15s, and 30s graphene oxide electrophoretically deposited on the surface of the pre-electrodeposited copper foil were characterized, such as... Figure 3 As shown. From Figure 3 It can be seen that as the electrophoresis time of the graphene oxide layer increases from 5s to 25s, the thermal conductivity of the composite material is higher than that of the electrodeposited pure copper foil (395.4 W·m). -1 ·K -1 Furthermore, it exhibits a trend of first increasing and then decreasing. The thermal conductivity reaches 439.60 W·m⁻¹ when the electrophoresis time is 15 s. -1 ·K -1 Compared to electrodeposited pure copper, the thermal conductivity was improved by 28.5%. When the electrophoresis time of the graphene oxide layer was further increased to 30 s, the thermal conductivity of the composite foil began to fall below that of the electrodeposited pure copper foil. Graphene oxide deposited at an appropriate electrophoresis time (15 s) exhibited a better deposition state and could also effectively improve the microstructure and thermal properties of the composite material.

[0045] Example 2

[0046] This embodiment provides a method for preparing a brick-mud composite material, the specific method of which is as follows:

[0047] (1) A copper plating layer was electrodeposited on the surface of a graphite sheet using a DP3020 DC power supply. The plating solution used in this invention consisted of: CuSO4·5H2O 220 g / L (55 g), concentrated sulfuric acid (98%) 65 g / L (16.25 g), and hydrochloric acid 30 mg / L (14.6 g). The pH of the plating solution was 1, the temperature was room temperature (25°C), and ultrasonic treatment was used as an auxiliary process during electrodeposition. A dual-electrode electrodeposition method was used to uniformly deposit a copper plating layer on one side of the graphite sheet, with a current density of 9 A / dm³. 2 .

[0048] (2) Graphene oxide was electrophoretically deposited on the prepared electrodeposition copper substrate using a DP3020 DC power supply. The plating solution composition was as follows: graphene oxide slurry concentration was 0.4 g / L, and its amount was 10 g; PAA500 concentration was 0.08 g / L, and its amount was 0.02 g. The electrophoretic deposition time was set to 15 s.

[0049] (3) After electrophoretic deposition of graphene oxide, the electrophoretically deposited copper / graphene oxide composite material is used as the cathode, and copper plating is electrodeposited again on its surface using the same process (same as step (1)).

[0050] (4) Repeat steps (2) and (3) to deposit 1, 2, 3, 4 and 5 layers of graphene oxide by electrophoresis. The thickness of the composite material is controlled at 100 μm. Finally, the composite layer is peeled off to obtain a brick-mud structured laminated composite material.

[0051] The thermal conductivity of composite materials containing different amounts of graphene oxide interlayers was characterized, such as... Figure 4 As shown. The thickness of the multilayer composite material is controlled at approximately 100 μm. (From...) Figure 4 It can be seen that when the number of graphene oxide interlayers is low, the thermal conductivity of the composite material exceeds that of electrodeposited pure copper foil (395.4 W·m). -1 ·K -1 As the number of graphene oxide interlayers increases, the thermal conductivity of the composite material begins to decrease. The thermal conductivity of composite materials containing 4 or 5 layers of graphene oxide is lower than that of pure copper foil. The distribution and reduction degree of graphene oxide in the copper matrix, as well as its good bonding with the copper matrix, are key factors in improving the thermal conductivity of the composite material. An appropriate graphene oxide content helps to improve the thermal conductivity of the composite material.

[0052] Comparative Example 1

[0053] The difference between this comparative example and Example 1 is that: in step (2), the electrophoretic deposition time of graphene oxide is 5 s; in step (3), the current density of the electrodeposited copper coating is 9 A / dm². 2 The electrodeposition time was 3 seconds.

[0054] Comparative Example 2

[0055] The difference between this comparative example and Example 1 is that: in step (2), the electrophoretic deposition time of graphene oxide is 15 s; in step (3), the current density of the electrodeposited copper coating is 9 A / dm². 2 The electrodeposition time was 30 seconds.

[0056] Comparative Example 3

[0057] The difference between this comparative example and Example 1 is that: in step (2), the electrophoretic deposition time of graphene oxide is 30 s; in step (3), the current density of the electrodeposited copper coating is 9 A / dm². 2 The electrodeposition time was 300 s.

[0058] The microstructure of the pre-deposited copper surface electrophoretically deposited graphene oxide layers at 5s, 15s, and 30s s, followed by 3s, 30s, and 300s copper plating, was characterized, such as... Figure 5 As shown. Figure 5 (ac) When the electrodeposition time is 3s, i.e., the initial stage of copper grain growth, the cathode surface containing the 5s electrophoretic layer is dotted with fine copper grains. Electrodeposition continues to 30s, and the fine copper grains grow into bulk grains and begin to contact each other. When electrodeposition reaches 300s, the copper grains grow further, covering the electrophoretic graphene oxide layer and forming a dense, cellular top copper layer. For example... Figure 5 (df), the cathode surface containing the 15s electrophoretic layer shows similar changes, only with fewer copper grains initially. For example... Figure 5 Unlike the previous two, the cathode surface containing the 30s electrophoretic graphene oxide layer exhibits the growth of large columnar dendrites at 30s of electrodeposition. These dendrites grow and eventually contact each other, forming a copper layer with large grain size, loose porosity, and poor density. Agglomerated graphene oxide also exists on the surface (circled in red). Therefore, optimizing the thickness and density of the electrophoretic graphene oxide interlayer, as well as the thickness of the electrodeposited copper, is crucial for controlling the overall performance of the copper / graphene oxide / copper composite material.

[0059] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the interpretation of the present invention, without departing from the scope of the invention, should be within the protection scope of the present invention.

Claims

1. A method for preparing a copper-graphene oxide brick-mud structure composite material with high thermal conductivity, characterized in that, Includes the following steps: (1) Copper is deposited on the substrate using an electrodeposition process to obtain an electrodeposited copper substrate; During electrodeposition, the current density is 3~12 A / dm³. 2 The electrodeposition time is 15~25 min; (2) Graphene oxide is deposited on the electrodeposited copper substrate prepared in step (1) by electrophoretic deposition process to obtain graphene oxide / copper composite material; During the electrophoretic deposition process, the applied voltage was fixed at 10 V, and the electrophoresis time was 0~30 s; (3) Copper is deposited on the graphene oxide / copper composite material prepared in step (2) by electrodeposition process to obtain copper / graphene oxide / copper laminate composite material; (4) Repeat steps (2) and (3) n times to obtain copper-graphene oxide brick-mud structure composite material; Where n is an integer greater than or equal to 0.

2. The method for preparing the high thermal conductivity copper-graphene oxide brick-mud structure composite material according to claim 1, characterized in that, In step (1), during the electrodeposition process, the plating solution consists of CuSO4·5H2O, concentrated sulfuric acid and hydrochloric acid.

3. The method for preparing the high thermal conductivity copper-graphene oxide brick-mud structure composite material according to claim 2, characterized in that, The pH of the plating solution is 1.

4. The preparation method of the high thermal conductivity copper-graphene oxide brick-mud structure composite material according to claim 3, characterized in that, The substrate is placed in the plating solution and electrodeposition is performed using a dual-electrode process. The anode is a pure copper plate with a purity of 99.9%, and the cathode is a graphite sheet.

5. The method for preparing the high thermal conductivity copper-graphene oxide brick-mud structure composite material according to claim 1, characterized in that, In step (2), during the electrophoretic deposition process, the plating solution consists of graphene oxide slurry and PAA500.

6. The method for preparing the high thermal conductivity copper-graphene oxide brick-mud structure composite material according to claim 5, characterized in that, The electrodeposited copper substrate is placed in the plating solution, and dual-electrode electrodeposition is performed. The anode is a graphite sheet pre-plated with copper, and the cathode is a pure copper plate with a purity of 99.9%.

Images