Three-dimensional graphene copper composite material based on in-situ interface chemical bonding and preparation method and application thereof

Abstract

The invention discloses a three-dimensional graphene copper composite material based on in-situ interface chemical bonding and a preparation method and application of the three-dimensional graphene copper composite material, relates to the technical field of metal-based composite materials, and solves the problems of graphene dispersion and interface bonding. The preparation method of the three-dimensional graphene copper composite material comprises the following steps: dissolving soluble copper salt and an organic ligand in water to form a complex solution, adding copper powder into the complex solution, uniformly mixing, and drying to obtain precursor coated copper powder; and carrying out spark plasma sintering or vacuum hot pressed sintering on the precursor coated copper powder to obtain the copper powder. A three-dimensional interpenetrating continuous network formed by graphene is arranged in the prepared three-dimensional graphene copper composite material, the interface of the graphene and a copper matrix is a chemical bonding interface, the comprehensive performance is excellent, and the composite material has high conductivity (gt; 103% IACS) and a high strength (gt; the comprehensive performance of the composite material is far better than that of a composite material prepared by a traditional method, and the composite material is suitable for high-end electric conduction, heat conduction and structural function integrated components.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal matrix composites, in particular to a three-dimensional graphene copper composite based on in-situ interface chemical bonding and a preparation method and application thereof. BACKGROUND

[0002] Copper is an indispensable basic material in the fields of power, electronics and heat dissipation due to its excellent electrical and thermal conductivity. However, its low strength and softening resistance at high temperature limit its application in high-end fields. Graphene has extremely high carrier mobility and theoretical strength and is considered as an ideal reinforcing body to improve the performance of copper materials.

[0003] Currently, the mainstream methods for preparing graphene / copper composites include: 1) powder metallurgy: copper powder is physically mixed with graphene or graphene oxide (GO) and then subjected to ball milling, compaction and sintering. This method easily leads to severe agglomeration of graphene, which not only fails to play its reinforcing role but also introduces additional electron scattering due to poor interface bonding (mainly van der Waals force), resulting in a decrease in electrical conductivity. 2) Electrodeposition: graphene dispersion is added to a copper-containing electrolyte to obtain a composite by co-deposition. This method is difficult to accurately control the distribution and orientation of graphene, and pores and defects are easily produced in the deposited layer, resulting in poor compactness. 3) Chemical vapor deposition (CVD)-composite method: graphene is grown on a copper foil or a three-dimensional copper framework, and then subjected to hot pressing or other compounding. This method can obtain high-quality graphene, but the subsequent transfer and compounding process is complex and costly, and it is difficult to avoid damage and contamination of graphene during the transfer process, and the interface problem is still prominent. The existing technologies such as patents CN202510039205.9, CN202411905910.4, CN202411773671.1 and CN201910299341.6 all adopt physical mixing or post-modification approach, and the common bottleneck is that the interface bonding between graphene and copper matrix is weak, and graphene is difficult to uniformly disperse and form an effective interconnected network in the matrix. This results in that the electrical conductivity, thermal conductivity and mechanical properties of the composite material do not reach the theoretical expectation. SUMMARY

[0004] In view of the above deficiencies, the present application provides a high-performance graphene copper composite with high interface bonding strength between graphene and copper matrix and three-dimensional continuous network of uniformly distributed graphene, and the specific technical solution is as follows: A preparation method of a three-dimensional graphene copper composite based on in-situ interface chemical bonding, comprising the following steps: Step 1: Dissolve a soluble copper salt and an organic ligand in water to form a complex solution, add copper powder to the complex solution and mix uniformly, and dry to obtain a precursor-coated copper powder; Step 2: Put the precursor coated copper powder into a graphite mold to conduct spark plasma sintering or vacuum hot-press sintering, and obtain the product.

[0005] Preferably, in step 1, the soluble copper salt is one of copper nitrate, copper sulfate or copper acetate.

[0006] Preferably, in step 1, the organic ligand is one or more of citric acid, tartaric acid, gluconic acid or amino acid.

[0007] Preferably, in step 1, the copper powder is electrolytic copper powder or atomized spherical copper powder, and the average particle size is 1-50 μm.

[0008] Preferably, in step 1, the mass-volume ratio of the soluble copper salt to water is 1: (40-80), and the mass ratio of the soluble copper salt, the organic ligand and the copper powder is (2-10):1: (50-100).

[0009] Preferably, in step 2, the sintering process is divided into two stages. The first stage: after vacuumizing, the temperature is raised to 300-500 ℃ at a rate of 10-15 ℃ / min, and the temperature is kept for 10-20 min, so that the organic metal complex is decomposed and carbonized, graphene is in-situ grown on the surface of the copper powder, and an interface chemical bond is formed. The second stage: the temperature is continuously raised to 800-900 ℃ at a rate of 10-20 ℃ / min, and a pressure of 40-50 MPa is applied, and the temperature and pressure are kept for 10-20 min, so that the copper powder is densified and a three-dimensional graphene network is formed.

[0010] Preferably, in step 2, the sintering is conducted under vacuum or in a reducing atmosphere.

[0011] The application also provides a three-dimensional graphene copper composite based on in-situ interface chemical bonding prepared by the above preparation method, wherein the graphene reinforcement forms a three-dimensional interpenetrating continuous network structure in the copper matrix, and the interface between the graphene and the copper matrix is a Cu-C bonding interface.

[0012] The application also provides an application of the three-dimensional graphene copper composite based on in-situ interface chemical bonding in the field of power transmission.

[0013] Compared with the prior art, the core of the application is to abandon the traditional physical mixing or post-modification idea, and turn to a strategy combining "precursor design" and "in-situ reaction". The core innovation points are: interface "molecular level welding": by designing an organic metal precursor containing Cu-C chemical bond, in the thermal decomposition process, copper atoms and carbon atoms can self-assemble to form graphene through chemical bonds, and at the same time form strong chemical bonding (Cu-C bond) with the copper matrix, thereby realizing the "welding" of graphene and copper at the molecular level, and fundamentally solving the problems of weak interface bonding and serious phonon scattering. Build a "three-dimensional interpenetrating network": the precursor is uniformly distributed in the copper matrix, and a continuous, uniform and interpenetrating three-dimensional graphene network can be generated in-situ in the copper matrix after thermal decomposition. This network not only provides an ultrafast channel for electrons, but also serves as a reinforcing skeleton, significantly improving the strength and high-temperature softening resistance of the material.

[0014] Compared with the prior art, the application has the following beneficial effects: 1. The application coats the copper powder with a precursor before sintering, and the organic metal precursor can be decomposed in-situ, realizing the chemical bonding of graphene and copper matrix at atomic scale ("molecular level welding"), greatly reducing the interface resistance, reducing electron and phonon scattering, and laying a solid foundation for obtaining ultra-high conductivity.

[0015] 2. The application coats the copper powder with a precursor before sintering, which can naturally generate graphene on the surface of each copper powder particle, and naturally form a three-dimensional interpenetrating network during sintering, perfectly solving the dispersion problem of graphene, and providing an efficient path for electron and heat transmission.

[0016] 3. The three-dimensional graphene copper composite material prepared by the application has excellent comprehensive performance, with high conductivity (>103% IACS) and high strength (>350 MPa), and its comprehensive performance far exceeds that of the composite material prepared by traditional methods.

[0017] 4. The process of the application is simple and efficient, without complex CVD growth, transfer process or long-time ball milling process, and the process flow is short, the energy consumption is relatively low, and the SPS sintering is fast and efficient, which can effectively inhibit grain growth and is beneficial to large-scale preparation. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description.

[0019] Figure 1 The technical route of the preparation process of the application; Figure 2 The SEM morphology of the spherical copper powder raw material with an average particle size of 1 μm in Example 1; Figure 3 TEM microstructure morphology of the three-dimensional graphene copper composite ingot prepared in Example 1; Figure 4 Electron energy loss spectrum (EELS) at the three-dimensional graphene-copper composite interface in the three-dimensional graphene copper composite ingot prepared in Example 1. DETAILED DESCRIPTION

[0020] The specific embodiments of the present application are described in detail below, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments.

[0021] Example 1 A preparation method of a three-dimensional graphene copper composite based on in-situ interface chemical bonding, the steps are as follows: Step 1, 4 g of copper nitrate (Cu(NO3)3·3H2O) and 1 g of citric acid are dissolved in 200 ml of deionized water, and a blue clear solution is formed by magnetic stirring; then 50 g of electrolytic copper powder with an average particle size of 1 μm (the SEM morphology thereof is shown in Figure 2 ) is added, stirred and ultrasonically dispersed for 2 hours; then dried in a 80 ℃ vacuum drying oven for 12 hours to obtain a precursor-coated copper powder.

[0022] Step 2, the dried composite powder is loaded into a Φ50 mm graphite mold, placed in an SPS sintering furnace, vacuumed to 10 -2 Pa, heated to 400 ℃ at 15 ℃ / min, and kept for 15 min (first stage); then continue to heat to 900 ℃ at 20 ℃ / min, and apply a pressure of 40 MPa, and keep for 10 min (second stage).

[0023] Step 3, after sintering, the furnace is cooled to room temperature, and a dense three-dimensional graphene copper composite ingot is obtained.

[0024] Performance test: the material has a conductivity of 104% IACS, a Vickers hardness of 125 HV, and a tensile strength of 380 MPa.

[0025] Example 2 A preparation method of a three-dimensional graphene copper composite based on in-situ interface chemical bonding, the steps are as follows: Step 1, 2 g of copper acetate (Cu(CH3COO)2) and 1 g of gluconic acid are dissolved in 200 ml of deionized water, and a clear solution is formed by magnetic stirring, then 100 g of electrolytic copper powder with an average particle size of 40 μm is added, stirred and ultrasonically dispersed for 2 hours, then dried in a 80 ℃ vacuum drying oven for 12 hours to obtain a precursor-coated copper powder.

[0026] Step 2, the dried composite powder is loaded into a Φ40 mm graphite mold, which is placed in a vacuum hot-pressing sintering furnace, vacuumed to 10 -2 Pa, and then heated to 400 ℃ at a rate of 10 ℃ / min, and kept for 20 min (first stage). Then, it is continuously heated to 900 ℃ at a rate of 10 ℃ / min, and a pressure of 50 MPa is applied, and kept for 20 min (second stage).

[0027] Step 3, after sintering, the furnace is cooled to room temperature, and a dense three-dimensional graphene copper composite ingot is obtained.

[0028] Performance test: the material has an electrical conductivity of 105% IACS, a Vickers hardness of 118 HV, and a tensile strength of 350 MPa.

[0029] Example 3 A preparation method of a three-dimensional graphene copper composite based on in-situ interface chemical bonding, the steps are as follows: Step 1, 10 g of copper nitrate (Cu(NO3)2·3H2O) and 2.5 g of amino acid and 2.5 g of citric acid are dissolved in 500 ml of deionized water, and a clear solution is formed by magnetic stirring, then 300 g of electrolytic copper powder with an average particle size of 10 μm is added, stirred and ultrasonically dispersed for 2 hours, and then dried in a 80 ℃ vacuum drying oven for 12 hours to obtain a precursor coated copper powder.

[0030] Step 2, the dried composite powder is loaded into a Φ50 mm graphite mold, which is placed in a vacuum hot-pressing sintering furnace, vacuumed to 10 -2 Pa, and then heated to 500 ℃ at a rate of 10 ℃ / min, and kept for 10 min (first stage), then continuously heated to 900 ℃ at a rate of 10 ℃ / min, and a pressure of 50 MPa is applied, and kept for 10 min (second stage).

[0031] Step 3, after sintering, the furnace is cooled to room temperature, and a dense three-dimensional graphene copper composite ingot is obtained.

[0032] Performance test: the material has an electrical conductivity of 104% IACS, a Vickers hardness of 140 HV, and a tensile strength of 400 MPa.

[0033] Example 4 A preparation method of a three-dimensional graphene copper composite based on in-situ interface chemical bonding, the steps are as follows: Step 1, 4 g of copper sulfate (CuSO4·5H2O) and 1 g of tartaric acid were dissolved in 400 ml of deionized water, and a clear solution was formed by magnetic stirring, then 100 g of electrolytic copper powder with an average particle size of 1 μm was added, stirred and ultrasonically dispersed for 2 hours, and then dried in a vacuum drying oven at 80 ℃ for 12 hours to obtain a precursor coated copper powder.

[0034] Step 2, the dried composite powder was loaded into a Φ50 mm graphite mold, placed in an SPS sintering furnace, vacuumed to 10 -2 Pa, heated to 400 ℃ at a rate of 15 ℃ / min, and held for 15 min (first stage), then continued to heat to 900 ℃ at a rate of 20 ℃ / min, and applied a pressure of 40 MPa, and held for 10 min (second stage).

[0035] Step 3, after sintering, the furnace was cooled to room temperature, and a dense three-dimensional graphene copper composite ingot was obtained.

[0036] Performance test: the material has an electrical conductivity of 104% IACS, a Vickers hardness of 135 HV, and a tensile strength of 390 MPa.

[0037] Example 5 A method for preparing a three-dimensional graphene copper composite based on in-situ interfacial chemical bonding, the steps are as follows: Step 1, 10 g of copper nitrate (Cu(NO3)2·3H2O) and 2 g of citric acid, 2 g of tartaric acid and 1 g of gluconic acid were dissolved in 600 ml of deionized water, and a blue clear solution was formed by magnetic stirring, then 200 g of electrolytic copper powder with an average particle size of 3 μm was added, stirred and ultrasonically dispersed for 2 hours, and then dried in a vacuum drying oven at 80 ℃ for 12 hours to obtain a precursor coated copper powder.

[0038] Step 2, the dried composite powder was loaded into a Φ50 mm graphite mold, placed in an SPS sintering furnace, vacuumed to 10 -2 Pa, heated to 400 ℃ at a rate of 15 ℃ / min, and held for 15 min (first stage), then continued to heat to 900 ℃ at a rate of 20 ℃ / min, and applied a pressure of 40 MPa, and held for 10 min (second stage).

[0039] Step 3, after sintering, the furnace was cooled to room temperature, and a dense three-dimensional graphene copper composite ingot was obtained.

[0040] Performance test: the material has an electrical conductivity of 103% IACS, a Vickers hardness of 130 HV, and a tensile strength of 370 MPa.

[0041] Figure 3 TEM microstructure morphology of the three-dimensional graphene copper composite ingot prepared for Example 1, Figure 3 The copper matrix and the three-dimensional continuous graphene network structure are shown, which indicates that the method of the present application can naturally generate graphene on the surface of each copper powder particle and naturally form a three-dimensional interpenetrating network during sintering, perfectly solving the dispersion problem of graphene and providing an efficient path for the transmission of electrons and heat.

[0042] Figure 4 Electron energy loss spectrum (EELS) at the three-dimensional graphene-copper composite interface in the three-dimensional graphene copper composite ingot prepared for Example 1, Figure 4 The Cu-C bond is generated at the graphene copper composite interface, which indicates that the present application can realize the chemical bonding of graphene and the copper matrix at the atomic scale (molecular level welding) by coating the copper powder with a precursor and then sintering, the organic metal precursor can be in-situ decomposed, greatly reducing the interface resistance and reducing the scattering of electrons and phonons, laying a solid foundation for obtaining ultra-high conductivity.

[0043] The foregoing description of specific exemplary embodiments of the present application is intended to be illustrative only and is not intended to limit the present application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the present application. The particular exemplary embodiments were chosen and described in order to explain the principles of the present application and its practical application to thereby enable others skilled in the art to best utilize the present application and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the present application be defined by the claims and their equivalents.

Claims

1. A method for preparing a three-dimensional graphene copper composite based on in-situ interfacial chemical bonding, characterized in that, The method comprises the following steps: Step 1: dissolving a soluble copper salt and an organic ligand in water to form a complex solution, adding copper powder into the complex solution and mixing, drying to obtain a precursor coated copper powder; Step 2: performing spark plasma sintering or vacuum hot-press sintering on the precursor coated copper powder to obtain the three-dimensional graphene copper composite material.

2. The method of claim 1, wherein the method is characterized by: In step 1, the soluble copper salt is one of copper nitrate, copper sulfate or copper acetate.

3. The method of claim 1, wherein the method is characterized by: In step 1, the organic ligand is one or more of citric acid, tartaric acid, gluconic acid or amino acid.

4. The method of claim 1, wherein the method is characterized by: In step 1, the copper powder is electrolytic copper powder or atomized spherical copper powder with an average particle size of 1-50 μm.

5. The method of claim 1, wherein the method is characterized by: In step 1, the mass / volume ratio of the soluble copper salt to water is 1: (40-80), and the mass ratio of the soluble copper salt, the organic ligand and the copper powder is (2-10):1: (50-100).

6. The method of claim 1, wherein the method is characterized by: In step 2, the sintering process is divided into two stages: First stage: after vacuumizing, heating to 300-500 ℃ at a rate of 10-15 ℃ / min and keeping for 10-20 min; Second stage: continuing to heat to 800-900 ℃ at a rate of 10-20 ℃ / min and applying a pressure of 40-50 MPa, keeping for 10-20 min.

7. The method of claim 1, wherein the method is characterized by: In step 2, the sintering is performed under vacuum or in a reducing atmosphere.

8. A three-dimensional graphene copper composite based on in-situ interfacial chemical bonding prepared by the method of any one of claims 1-7, wherein, In the material, the graphene reinforcement forms a three-dimensional interpenetrating continuous network structure in the copper matrix, and the interface between the graphene and the copper matrix is a Cu-C bonding interface.

9. Application of the three-dimensional graphene copper composite material based on in-situ interface chemical bonding according to claim 8 in the field of power transmission.

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