CN108149046B - High-strength and high-conductivity graphene/copper nano composite material and preparation method and application thereof - Google Patents

Abstract

The invention relates to a high-strength and high-conductivity graphene/copper composite material and a preparation method and application thereof. The copper matrix of the composite material is uniformly distributed in a three-dimensional nanoscale manner, and the dimension is 10-100 nm, preferably 30-80 nm; the graphene is in a three-dimensional interconnected network structure in the composite material, and the average layer number is 1-10. The graphene/copper nano composite material obtained by the method has the characteristics of high strength, high modulus and high conductivity, and can be used as various types of conducting 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, a preparation method and application thereof, and belongs 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 ≥ 550MPa, elastic modulus ≥ 140GPa, 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 introduction of carbon material reinforced 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 matrix composites. High strength (≥550MPa), high modulus (≥140GPa), high conductivity (≥90% IACS) properties provide the possibility. The literature search on the prior art found that the literature (1) "Ultrahigh Strength and High Electrical Conductivity in Copper" (Ultrahigh Strength and High Electrical Conductivity in Copper) prepared pure copper samples with high-density nano-twins by pulse electrodeposition method, The average value of the twinned wafer layer is 15 nm, and the high-density nano-twinned grain boundaries can effectively limit the dislocation movement and have very low scattering ability for electron transport, so that the fracture strength of nano-twinned copper reaches 1068 MPa and the electrical conductivity is 98.4%. IACS. However, due to the lack of the introduction of high-modulus reinforcements, 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) combine graphene oxide nanosheets with copper ions through electrostatic agents Molecular-level mixing was performed by adsorption to obtain graphene oxide/copper ions (GO/Cu ²⁺ ), and then reduced graphene oxide/copper (rGO/Cu) composites were obtained by oxidation, reduction and sintering. The internal copper matrix of the composite material has a sub-micron scale (100nm-500nm), and a 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%, the composite tensile strength is 335MPa, and the elastic modulus The amount of 131GPa, the conductivity of 50% IACS, does not meet the requirements of use. Reference (3) "Aligning graphene in bulk copper: Nacre-inspired nanolaminatedarchitecture coupled with in-situ processing for enhanced mechanicalproperties and high electrical conductivity" The nano-laminated structure inspired by layer and in-situ process) ball-milled commercial spherical copper powder to obtain flake-like morphology, and coated PMMA on the surface of flake copper powder with organic solvent. The graphene/copper flake composite powder is obtained, and finally the nano-stack graphene/copper composite material is obtained by hot pressing sintering and hot rolling process. The thickness of the inner copper matrix sheet of the composite material is sub-micron scale (~660nm), the volume fraction of the reinforcement is 2.5%, the tensile strength of the composite material is 378MPa, and the elastic modulus is 135GPa, which does not meet the requirements for use. However, the introduction of high-quality in situ-grown graphene enabled the composite to maintain a high electrical conductivity (93.8% IACS).

Therefore, to summarize the characteristics and defects of the prior art, the preparation of high-strength and high-conductivity graphene/copper composites with tensile strength ≥550MPa, elastic modulus ≥140GPa, and 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 hindering effect of grain boundaries on dislocation movement and improves the strength of the copper matrix; (2) The introduction of high-density graphene/copper interface inside the composite material increases the interface It can hinder the movement of dislocations, and at the same time increase the volume fraction of graphene, so that the composite material can obtain high strength and high modulus; (3) The introduction of high-quality graphene exerts its inherent two-dimensional high conductivity and high electron mobility. properties, so that the composite material maintains high electrical conductivity.

SUMMARY OF THE INVENTION

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

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 uniformly distributed in three-dimensional nanometer scale, and the scale is between 10 and 100 nm, preferably 30 nm-80 nm; the graphene has a three-dimensional interconnected network structure inside the composite material, and the average number of layers 1 to 10 layers.

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

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

Wherein, the mass fraction of Mn or Ni in the binary alloy plate is 50-90% (eg 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 acid aqueous 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 H ₂ SO ₄ 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; and the solid carbon source is polymethyl methacrylate (PMMA) or polystyrene (PS). At the same time, according to different types of carbon sources, the 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: the flow rate of the gaseous carbon source is 1sccm～10sccm, the flow rate of hydrogen gas is 10sccm～30sccm, the flow rate of argon gas is 50sccm～150sccm, the pressure in the tube is kept below 1 Torr, 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 to be 1sccm～10sccm, the hydrogen flow to be 10sccm to 30sccm, and the argon flow to be 50sccm to 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, and keep the pressure in the tube < 200 mTorr until the furnace temperature is cooled to room temperature to obtain nanoporous graphene/copper.

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

(1) Add 0.5-5.0 g/L polymethyl methacrylate (PMMA) or polystyrene (PS) to the solvent by vacuum impregnation, stir evenly, and then introduce into the nanoporous copper structure, and then adjust the temperature at 70-90 ℃ (such as 80 ℃) drying to obtain nano-porous PMMA/copper or PS/copper; the statistics are anisole or chloroform;

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

(3) Keep the pressure in the tube < 200 mTorr until the furnace temperature is cooled to room temperature, that is, nano-porous graphene/copper is obtained.

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

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

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

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

(2) The existence of the high-density graphene/copper interface increases the volume fraction of high-modulus reinforced graphene inside the composite, making the composite have a high modulus (≥140 GPa).

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

Description of drawings

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

Detailed ways

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

Example 1

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

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

(2) 2.5 g/L polymethyl methacrylate anisole solution was introduced into the nanoporous copper structure by vacuum impregnation method, and then dried at 80° C. to obtain nanoporous PMMA/copper. The nanoporous PMMA/copper was placed in a tube furnace, the hydrogen flow was adjusted to 10 sccm, the argon flow was 150 sccm, and the pressure in the tube was kept <1 Torr. Graphene growth was carried out at a temperature of 900 °C for 1 hour. Keeping the pressure in the tube < 200 mTorr until the furnace temperature is cooled to room temperature, the 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, which meets the requirements for use.

Example 2

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

(1) The Cu-Ni binary alloy plate with a thickness of 500 μm and a mass fraction of Ni of 80% was electrochemically etched and de-alloyed, and the electrolyte was a 0.05Mol/L H ₂ SO ₄ aqueous solution; the potential difference was 0.20 V; The chemical etching time is 12 hours; the pore size of the obtained nanoporous copper is 50 nm.

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

(3) The nanoporous graphene/copper is subjected to discharge plasma hot pressing sintering at a temperature of 800° C. and a pressure of 100 MPa, and the holding time is 10 minutes to obtain a graphene/copper matrix 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, which meets the requirements for use.

Example 3

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

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

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

(3) The nanoporous graphene/copper is subjected to vacuum hot pressing sintering at a temperature of 700° C. and a pressure of 200 MPa, and the holding time is 60 minutes to obtain a graphene/copper matrix 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, which meets the requirements for use.

Example 4

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

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

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

(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, which meets the requirements for use.

The above are some preferred embodiments of the present invention. It should be understood that there are other embodiments of the present invention, such as changing the composition and thickness parameters of the Cu-Mn or Cu-Ni binary alloy plate in the above embodiments, electrochemical etching The parameters of electrolyte, potential difference, and etching time in the etching and 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. For personnel, it is very easy to achieve.

Although the present invention has been described in detail above with general description and specific embodiments, 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, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of the claimed protection of the present invention.

Claims (17)

1. a high-strength, high-conductivity graphene/copper composite material, is characterized in that, its copper matrix is uniform three-dimensional nanoscale distribution, and scale is between 10～100nm; The number is 1 to 10 layers; The preparation method of the composite material includes: Using Cu-Mn binary alloy plate or Cu-Ni binary alloy plate as anode, the nanoporous copper is obtained by electrochemical etching and de-alloying; a carbon source is introduced, and graphene is uniformly grown on the surface of nanoporous copper. Press sintering and densification to obtain graphene/copper composite material; Wherein, the carbon source is selected from gaseous carbon source and/or solid carbon source; When the carbon source is a gaseous carbon source, the graphene deposition conditions are: the flow rate of the gaseous carbon source is 1sccm～10sccm, the flow rate of hydrogen gas is 10sccm～30sccm, the flow rate of argon gas is 50sccm～150sccm, the pressure in the tube is kept below 1 Torr, and the temperature is 600 ℃～ 700℃; When the type of carbon source is a solid carbon source, a vacuum impregnation method is used to obtain nanoporous PMMA/copper or PS/copper, and then graphene growth is performed; the graphene growth conditions are: the hydrogen flow rate is 5 sccm to 15 sccm, and the argon gas flow rate is It is 100sccm～200sccm, keep the pressure in the tube <1 Torr, and the temperature is 800℃～1000℃. 2 . The composite material according to claim 1 , wherein the nanoscale is 30 nm-80 nm. 3 . 3. The composite material according to claim 1 or 2, wherein the composite material has a tensile strength of 580-650 MPa, an elastic modulus of 150-220 GPa, and an electrical conductivity of 90-97% IACS. 4. the preparation method of the arbitrary described high-strength, high-conductivity graphene/copper composite material of claim 1-3, is characterized in that, comprises: with Cu-Mn binary alloy plate or Cu-Ni binary alloy plate as The anode is electrochemically etched and de-alloyed to obtain nanoporous copper; a carbon source is introduced, and graphene is uniformly grown on the surface of the nanoporous copper, and is densified by hot pressing to obtain a graphene/copper composite material. 5 . The preparation method according to claim 4 , wherein 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. 6 . 6 . The preparation method according to claim 5 , wherein the thickness of the alloy plate is 100-500 μm. 7 . 7 . The preparation method according to claim 4 , wherein the electrolyte used in the electrochemical etching is an acid aqueous solution, and the potential difference is 0.01-0.30V. 8 . 8. The preparation method according to claim 7, wherein the potential difference is 0.05-0.30V. 9 . The preparation method according to claim 7 , wherein the electrolyte is an aqueous HCl solution, an aqueous H ₂ SO ₄ solution or an aqueous H ₃ PO ₄ solution. 10 . 10. The preparation method according to any one of claims 4-9, wherein the carbon source is selected from a gaseous carbon source and/or a solid carbon source. 11. The preparation method according to claim 10, wherein the gaseous carbon source is methane or acetylene. 12. The preparation method according to claim 10, wherein the solid carbon source is polymethyl methacrylate or polystyrene. 13. preparation method according to claim 11 is characterized in that, when carbon source is gaseous carbon source, graphene deposition condition is: gaseous carbon source flow rate is 1sccm～10sccm, hydrogen flow rate is 10sccm～30sccm, argon gas flow rate It is 50sccm～150sccm, keep the pressure in the tube <1 Torr, and the temperature is 600℃～700℃. 14. preparation method according to claim 12, 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 dipping conditions are as follows: the dipping solution is 0.5-5.0 g/L polymethyl methacrylate or polystyrene anisole or chloroform solution, 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 in the tube is kept below 1 Torr, and the temperature is 800 ℃-1000 ℃. 15. The preparation method according to claim 4, wherein the hot pressing sintering method is selected from one of hot pressing sintering under vacuum or gas protection, hot isostatic pressing sintering, spark plasma sintering or microwave sintering ; The sintering temperature range is 700~1000℃, and the pressure range is 10~200MPa. 16. The preparation method according to claim 15, wherein the pressure is 50-200 MPa. 17. The application of any one of the graphene/copper composite materials of claims 1-3 in the fields of electric power, electronics, and machinery industries.