CN108149046A - One kind is high-strength, high to lead graphene/copper nanocomposite and its preparation method and application - Google Patents

Abstract

The invention relates to a high-strength, high-conductivity graphene/copper composite material and a preparation method and application thereof. The copper matrix of the composite material is distributed in a uniform three-dimensional nanometer scale, and the scale is between 10-100nm, preferably 30nm-80nm; the graphene is in a three-dimensional interconnected network structure inside the composite material, and the average number of layers is 1-10 layers. The graphene/copper nanocomposite material obtained by the invention has the characteristics of high strength, high modulus and high electrical conductivity, and can be used as various types of conductive materials.

Description

A kind of high-strength, high-conductivity graphene/copper nanocomposite material and its preparation method and application

technical field

The invention relates to a high-strength and high-conductivity graphene/copper nanocomposite material and a preparation method and application thereof, belonging to the technical field of metal matrix composite materials.

Background technique

Pure copper is one of the metal materials with the lowest resistivity and is widely used in electric power, electronics, machinery and other industrial fields. However, pure copper has become increasingly difficult to meet the needs of industrial development due to its low mechanical properties. For example, the ideal performance indicators of electrified high-speed railway contact wires are tensile strength ≥ 550 MPa, elastic modulus ≥ 140 GPa, and electrical conductivity ≥ 90% IACS. Therefore, copper materials with high strength, high modulus and high electrical conductivity have become the focus of development.

In recent years, the research on the introduction of carbon material reinforcement graphene into metal matrix has gradually emerged. The high strength (tensile strength ~ 130GPa), high modulus (elastic modulus ~ 1TPa), and high electrical conductivity (electron mobility ~ 2×10 ⁵ cm ² /Vs) endowed by its unique structure are realized by copper-based composite materials High strength (≥550MPa), high modulus (≥140GPa), high electrical conductivity (≥90%IACS) properties provide the possibility. A literature search of the prior art found that literature (1) "Ultrahigh Strength and High Electrical Conductivity in Copper" (ultrahigh strength, high conductivity copper) prepared a pure copper sample with high-density nano-twins by pulse electrodeposition, The average value of the twinned crystal layer is 15nm. The high-density nano-twinned boundary effectively restricts the movement of dislocations and has a low scattering ability for electron transport, so that the fracture strength of nano-twinned copper reaches 1068MPa and the conductivity is 98.4%. IACS. However, due to the lack of high-modulus reinforcement, the elastic modulus of nano-twinned copper is between 110GPa and 120GPa, which does not meet the application requirements. Document (2) "Enhanced Mechanical Properties of Graphene/Copper Nanocomposites Using a Molecular-Level Mixing Process" (graphene/copper nanocomposites with improved mechanical properties using a molecular-level mixing process) uses graphene oxide nanosheets and copper ions through an electrostatic agent Adsorption performs molecular-level mixing to obtain graphene oxide/copper ions (GO/Cu ²⁺ ), followed by oxidation, reduction, and sintering to obtain reduced graphene oxide/copper (rGO/Cu) composites. The copper matrix inside the composite material is submicron scale (100nm~500nm), and the graphene oxide reinforcement whose mechanical and electrical properties are reduced due to structural damage is used. The volume fraction of the reinforcement is 2.5%, and the tensile strength of the composite material is 335MPa. The volume is 131GPa, and the conductivity is 50% IACS, which do not meet the requirements for use. Literature (3) "Aligning graphene in bulk copper: Nacre-inspired nanolaminated architecture coupled with in-situ processing for enhanced mechanical properties and high electrical conductivity" layer-inspired nano-stack structure and in-situ process) to mill the commercial spherical copper powder to obtain a flake-like morphology, use organic solvents to coat PMMA on the surface of the flake copper powder, and use the PMMA raw material under high temperature and hydrogen atmosphere conditions. Bits are converted into graphene to obtain graphene/copper flake composite powder, and finally nano-layered graphene/copper composite materials are obtained through hot pressing sintering and hot rolling processes. The thickness of the copper matrix sheet inside the composite material is submicron scale (~660nm), the reinforcement volume fraction is 2.5%, the tensile strength of the composite material is 378MPa, and the elastic modulus is 135GPa, which does not meet the use requirements. However, the introduction of high-quality in-situ grown graphene enables the composite to maintain a high electrical conductivity (93.8%IACS).

Therefore, summarizing the characteristics and defects of the prior art, the preparation of high-strength and high-conductivity graphene/copper composite materials with tensile strength ≥ 550MPa, modulus of elasticity ≥ 140GPa, electrical conductivity ≥ 90% IACS needs to solve the following technical problems: (1) The acquisition of nano-scale (<100nm) copper matrix inside the composite material increases the resistance of grain boundaries to dislocation movement and improves the strength of the copper matrix; (2) the introduction of high-density graphene/copper interfaces inside the composite material increases the interface The hindering effect on dislocation movement, while increasing the graphene volume fraction, so that the composite material can obtain high strength and high modulus; (3) the introduction of high-quality graphene, to play its two-dimensional high conductivity, high electron mobility intrinsic performance, so that the composite maintains high electrical conductivity.

Contents of the invention

In order to solve the above technical problems, the present invention constructs a copper matrix with uniform three-dimensional nanoscale distribution, introduces a carbon source on this basis, and finally sinters to obtain a high-strength, high-conductivity graphene/copper nanocomposite material.

The present invention is achieved through the following technical solutions.

A high-strength, high-conductivity graphene/copper composite material, the copper matrix of which is distributed in a uniform three-dimensional nanometer scale, and the scale is between 10-100nm, preferably 30nm-80nm; graphene has a three-dimensional interconnected network structure inside the composite material, and the average number of layers 1 to 10 floors.

The tensile strength of the composite material is 580-650 MPa, the elastic modulus is 150-220 GPa, and the electrical conductivity is 90-97% IACS.

The present invention also provides a preparation method for the above-mentioned high-strength, high-conductivity graphene/copper composite material, comprising: using a Cu-Mn binary alloy plate or a Cu-Ni binary alloy plate as an anode, and dealloying by electrochemical etching to obtain Nanoporous copper: carbon source is introduced, and graphene is uniformly grown on the surface of nanoporous copper, which is densified by hot pressing and sintering to obtain graphene/copper composite material.

Wherein, the mass fraction of Mn or Ni in the binary alloy plate is 50-90% (such as 70%, 80%), and the thickness of the alloy plate is 10-1000 μm, preferably 100-500 μm.

In the electrochemical etching step, the electrolyte is an aqueous acid solution, the potential difference is 0.01-0.30V, preferably 0.05-0.30V; the etching time is 0.5-50 hours. The electrolyte can be an aqueous HCl solution with a concentration of 0.01-0.50 mol/L, preferably 0.05-0.50 mol/L _; or an aqueous _H2SO4 solution with a concentration of 0.005-0.25 mol/L, preferably 0.025-0.25 mol/L ; or H ₃ PO ₄ aqueous solution, the concentration is 0.005-0.20 mol/L, preferably 0.02-0.20 mol/L.

The carbon source is selected from gaseous carbon source and/or solid carbon source; wherein, the gaseous carbon source is methane or acetylene; the solid carbon source is polymethyl methacrylate (PMMA) or polystyrene (PS). At the same time, according to different types of carbon sources, their introduction methods and graphene growth methods are also different, as follows:

When the carbon source is a gaseous carbon source, the graphene deposition conditions are as follows: the gaseous carbon source flow rate is 1 sccm ~ 10 sccm, the hydrogen gas flow rate is 10 sccm ~ 30 sccm, the argon gas flow rate is 50 sccm ~ 150 sccm, keep the pressure in the tube < 1Torr, and the temperature is 600 ℃ ~ 700°C. The specific implementation steps are as follows:

(1) Place the nanoporous copper in the tube furnace, adjust the gaseous carbon source flow rate to 1sccm-10sccm, the hydrogen flow rate to 10sccm-30sccm, the argon flow rate to 50sccm-150sccm, and keep the pressure in the tube <1Torr;

(2) Graphene deposition is carried out at a temperature of 600°C to 700°C, and the deposition time is 5 minutes to 20 minutes;

(3) Stop the introduction of the gaseous carbon source, keep the pressure in the tube <200mTorr until the furnace temperature is cooled to room temperature, and obtain nanoporous graphene/copper.

When the carbon source type is a solid carbon source, first use the vacuum impregnation method to obtain nanoporous PMMA/copper or PS/copper, and then grow graphene; the impregnation conditions are: the impregnation solution is 0.5-5.0g/L polymethyl The anisole or chloroform solution of methyl acrylate or polystyrene, the drying temperature is 70-90°C; the graphene growth conditions are: the flow rate of hydrogen is 5sccm-15sccm, the flow rate of argon gas is 100sccm-200sccm, and the pressure in the tube is maintained <1Torr, the temperature is 800°C~1000°C, and the time is 1~2 hours. The specific implementation steps are as follows:

(1) Add 0.5-5.0g/L polymethyl methacrylate (PMMA) or polystyrene (PS) into the solvent by vacuum impregnation method, stir well, and then introduce it into the nanoporous copper structure, and then in 70-90 °C (such as 80 °C) drying to obtain nanoporous PMMA/copper or PS/copper; the statistics are anisole or chloroform;

(2) Place nanoporous PMMA/copper or PS/copper in the tube furnace, adjust the flow rate of hydrogen to 5 sccm to 15 sccm, the flow rate of argon to 100 to 200 sccm, keep the pressure in the tube <1Torr, and keep the pressure in the tube at 800°C to 1000°C Graphene growth is carried out under the condition of ℃, and the time is 1 to 2 hours;

(3) Keep the pressure in the tube < 200mTorr until the furnace temperature is cooled to room temperature, and obtain nanoporous graphene/copper.

The hot press sintering can be selected from one of hot press sintering under vacuum or gas protection, hot isostatic pressing sintering, discharge plasma sintering, and microwave sintering; the sintering temperature range is 700-1000°C, and the pressure range is 10-200MPa , preferably 50-200MPa.

The present invention also provides the application of the above-mentioned graphene/copper composite material in the fields of electric power, electronics and machinery industry.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

(1) Compared with the submicron scale of the existing composite material, the copper matrix inside the composite material of the present invention is distributed in a uniform three-dimensional nanometer scale, and the grain boundary density of the matrix and the graphene/copper interface density are significantly improved, which increases the resistance to dislocation movement The hindering effect makes the composite material have high strength (≥550MPa).

(2) The presence of a high-density graphene/copper interface increases the volume fraction of high-modulus reinforcement graphene inside the composite, resulting in a high-modulus composite (≥140GPa).

(3) Graphene of the present invention grows on the nanopore surface, and itself presents a three-dimensional network structure inside the composite material; Graphene carbon atoms will obtain doped electrons from surrounding copper atoms, and the carriers at the graphene/copper interface will migrate The speed is significantly improved; the presence of this high-density, highly conductive graphene/copper interface enables the composite to maintain high electrical conductivity (≥90% IACS).

Description of drawings

Fig. 1 is a schematic diagram of the preparation method of the high-strength and high-conductivity graphene/copper nanocomposite material of the present invention.

Detailed ways

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

The present embodiment provides a kind of preparation of graphene/copper composite material, comprising:

(1) A Cu-Mn binary alloy plate with a thickness of 100 μm and a mass fraction of Mn of 70% is electrochemically etched and dealloyed, and the electrolyte is 0.25mol/L HCl aqueous solution; the potential difference is 0.10V; the electrochemical etching The time is 4 hours; the obtained nanoporous copper has a pore size of 30 nm.

(2) A 2.5 g/L polymethyl methacrylate anisole solution was introduced into the nanoporous copper structure by vacuum impregnation, and then dried at 80° C. to obtain nanoporous PMMA/copper. The nanoporous PMMA/copper is placed in a tube furnace, the flow rate of hydrogen gas is adjusted to 10 sccm, the flow rate of argon gas is 150 sccm, and the pressure in the tube is kept <1 Torr. Graphene growth is performed at a temperature of 900° C. for 1 hour. Keep the pressure in the tube < 200mTorr until the furnace temperature is cooled to room temperature, that is, nanoporous graphene/copper is obtained, and the number of graphene layers is 5-6.

(3) The nanoporous graphene/copper is hot-pressed and sintered under the protection of an argon atmosphere at a temperature of 900° C. and a pressure of 50 MPa, and the holding time is 60 minutes to obtain a graphene/copper-based composite material.

The obtained composite material has a tensile strength of 633 MPa, an elastic modulus of 209.6 GPa, and an electrical conductivity of 92.1% IACS, meeting the requirements for use.

Example 2

The present embodiment provides a kind of preparation of graphene/copper composite material, comprising:

(1) A Cu-Ni binary alloy plate with a thickness of 500 μm and a mass fraction of Ni of 80% is electrochemically etched and dealloyed, and the electrolyte is _0.05Mol /L _H2SO4 aqueous solution; the potential difference is 0.20V; The chemical etching time is 12 hours; the nanoporous copper pore size is 50nm.

(2) A 0.50 g/L polymethyl methacrylate chloroform solution was introduced into the nanoporous copper structure by vacuum impregnation, and then dried at 80° C. to obtain nanoporous PMMA/copper. The nanoporous PMMA/copper is placed in a tube furnace, the flow rate of hydrogen gas is adjusted to 15 sccm, the flow rate of argon gas is 200 sccm, and the pressure in the tube is kept <1 Torr. Graphene growth is performed at a temperature of 1000° C. for 1 hour. Keep the pressure in the tube < 200mTorr until the furnace temperature is cooled to room temperature, that is, nanoporous graphene/copper is obtained, and the number of graphene layers is 2-3 layers.

(3) The nanoporous graphene/copper is sintered by discharge plasma hot pressing at a temperature of 800° C. and a pressure of 100 MPa, and the holding time is 10 minutes to obtain a graphene/copper-based composite material.

The obtained composite material has a tensile strength of 587 MPa, an elastic modulus of 154.5 GPa, and an electrical conductivity of 94.6% IACS, meeting the requirements for use.

Example 3

The present embodiment provides a kind of preparation of graphene/copper composite material, comprising:

(1) A Cu-Mn binary alloy plate with a thickness of 1000 μm and a mass fraction of Mn of 90% is electrochemically etched and dealloyed, and the electrolyte is an aqueous HCl solution of 0.50Mol/L; the potential difference is 0.30V; the electrochemical etching The time is 20 hours; the pore diameter of the obtained nanoporous copper is 75nm.

(2) A 5.0 g/L polystyrene anisole solution was introduced into the nanoporous copper structure by vacuum impregnation, and then dried at 80°C to obtain nanoporous PS/copper. The nanoporous PS/copper is placed in a tube furnace, the flow rate of hydrogen gas is adjusted to 5 sccm, the flow rate of argon gas is 100 sccm, and the pressure in the tube is kept <1 Torr. Graphene growth was performed at a temperature of 800° C. for 2 hours. Keep the pressure in the tube <200mTorr until the furnace temperature is cooled to room temperature, and then obtain nanoporous graphene/copper, and the number of graphene layers is 8-9.

(3) The nanoporous graphene/copper is vacuum hot-pressed and sintered at a temperature of 700° C. and a pressure of 200 MPa, and the holding time is 60 minutes to obtain a graphene/copper-based composite material.

The obtained composite material has a tensile strength of 617 MPa, an elastic modulus of 186.4 GPa, and an electrical conductivity of 91.7% IACS, meeting the requirements for use.

Example 4

The present embodiment provides a kind of preparation of graphene/copper composite material, comprising:

(1) A Cu-Ni binary alloy plate with a thickness of 500 μm and a mass fraction of Ni of 70% is electrochemically etched and dealloyed, and the electrolyte is 0.05Mol/L H ₃ PO ₄ aqueous solution; the potential difference is 0.05V; The chemical etching time is 40 hours; the nanoporous copper pore size is 30nm.

(2) Place the nanoporous copper in the tube furnace, adjust the flow rate of gaseous carbon source acetylene to 5 sccm, the flow rate of hydrogen gas to 20 sccm, and the flow rate of argon gas to 100 sccm, and keep the pressure in the tube < 1 Torr. Graphene deposition was carried out at a temperature of 650° C., and the deposition time was 10 minutes. Then stop the introduction of the gaseous carbon source, keep the pressure in the tube <200mTorr until the furnace temperature is cooled to room temperature, and then obtain nanoporous graphene/copper, and the number of graphene layers is 1-2 layers.

(3) The nanoporous graphene/copper is hot-pressed and sintered under the protection of an argon atmosphere at a temperature of 900° C. and a pressure of 50 MPa, and the holding time is 60 minutes to obtain a graphene/copper-based composite material.

The obtained composite material has a tensile strength of 595 MPa, an elastic modulus of 158.2 GPa, and an electrical conductivity of 96.8% IACS, meeting the requirements for use.

The above are some preferred embodiments of the present invention. It should be understood that the present invention also has other implementations, such as changing the composition and thickness parameters of the Cu-Mn or Cu-Ni binary alloy plate in the above-mentioned embodiments, electrochemical engraving The electrolyte, potential difference, and etching time parameters in the alloying process, the carbon source concentration, temperature, atmosphere, and time parameters in the graphene growth process, and the temperature, pressure, and time parameters in the densification process are essential to the technology in this field. For personnel, it is very easy to implement.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. A high-strength, high-conductivity graphene/copper composite material is characterized in that its copper matrix is distributed in a uniform three-dimensional nanometer scale, and the scale is between 10-100nm, preferably 30nm-80nm; graphene is three-dimensionally interconnected in the composite material Network structure, the average number of layers is 1 to 10 layers. 2. The composite material according to claim 1, characterized in that the tensile strength of the composite material is 580-650 MPa, the modulus of elasticity is 150-220 GPa, and the electrical conductivity is 90-97% IACS. 3. A preparation method of high-strength, high-conductivity graphene/copper composite material, is characterized in that, comprises: take Cu-Mn binary alloy plate or Cu-Ni binary alloy plate as anode, remove alloy through electrochemical etching Nanoporous copper is obtained; a carbon source is introduced, and graphene is uniformly grown on the surface of nanoporous copper, and the graphene/copper composite material is obtained through hot-pressing sintering and densification. 4. The preparation method according to claim 3, characterized in that the mass fraction of Mn or Ni in the binary alloy plate is 50-90%, and the thickness of the alloy plate is 10-1000 μm, preferably 100-500 μm. 5. The preparation method according to claim 3 or 4, characterized in that the electrolyte is an aqueous acid solution, and the potential difference is 0.01-0.30V, preferably 0.05-0.30V; The electrolyte is preferably aqueous HCl, aqueous H ₂ SO ₄ or aqueous H ₃ PO ₄ . 6. according to the preparation method described in any one of claim 3-5, it is characterized in that, described carbon source is selected from gaseous carbon source and/or solid carbon source; The gaseous carbon source is preferably methane or acetylene; The solid carbon source is preferably polymethyl methacrylate or polystyrene. 7. The preparation method according to claim 6, characterized in that, when the carbon source is a gaseous carbon source, the graphene deposition conditions are: the gaseous carbon source flow rate is 1sccm～10sccm, the hydrogen flow rate is 10sccm～30sccm, the argon flow rate 50sccm~150sccm, keep the pressure in the tube <1Torr, and keep the temperature at 600°C~700°C. 8. preparation method according to claim 6, is characterized in that, when carbon source kind is solid carbon source, utilize vacuum impregnation method to obtain nanoporous PMMA/copper or PS/copper earlier, then carry out graphene growth; The impregnation conditions are as follows: the impregnation solution is 0.5-5.0 g/L polymethyl methacrylate or anisole or chloroform solution of polystyrene, and the drying temperature is 70-90°C; The graphene growth conditions are as follows: the flow rate of hydrogen gas is 5 sccm-15 sccm, the flow rate of argon gas is 100 sccm-200 sccm, the pressure inside the tube is kept <1 Torr, and the temperature is 800°C-1000°C. 9. The preparation method according to any one of claims 3-8, wherein the hot press sintering method is selected from hot press sintering under vacuum or gas protection, hot isostatic pressing sintering, spark plasma sintering or microwave sintering One of them; the sintering temperature range is 700-1000°C, and the pressure range is 10-200MPa, preferably 50-200MPa. 10. the application of the graphene/copper composite material described in claim 1 or 2 in electric power, electronics, machinery industry field.