Amorphous carbon / copper composite wire and preparation method thereof

Abstract

According to the amorphous carbon / copper composite wire and the preparation method thereof provided by the invention, from the perspective of graphene amorphization, laser irradiation is carried out on a graphene / copper composite material prepared by reel-to-reel chemical vapor deposition, and carbon atoms in graphene are induced by laser to form abundant pentagonal and heptagonal carbon rings; an amorphous structure is constructed under the environmental condition, the amorphous carbon / copper composite wire is obtained, and the prepared composite wire has high conductivity (gt; 105% IACS) and excellent mechanical strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper processing and manufacturing, and particularly relates to an amorphous carbon / copper composite wire and a preparation method thereof. BACKGROUND

[0002] Since the emergence of graphene, researchers have conducted a large number of studies, and obtained a variety of methods for enhancing metal-based composite materials with graphene. In these methods, chemical vapor deposition can be used to prepare graphene with good interface bonding and complete intrinsic structure. At present, the patent system for preparing graphene / metal composite materials by chemical vapor deposition is very complete.

[0003] A Chinese invention patent with the application publication number CN 113699503 A discloses a graphene preparation method and device with a multi-phase composite carbon source on a metal surface, which expands the optional range of the carbon source and metal substrate material. A Chinese invention patent with the application publication number CN 111118470 A discloses a composite metal wire with a composite coated graphene on the surface, and a composite metal wire with super-thick graphene on the surface is prepared. A Chinese invention patent with the application publication number CN 111058017 A discloses a graphene metal composite wire and a low-temperature continuous preparation method thereof, and the low-temperature continuous preparation of the graphene metal composite wire is realized by a plasma enhanced chemical vapor deposition process.

[0004] The above patents construct a complete preparation framework for graphene / metal composite materials from the angles of carbon source selection, metal substrate selection, graphene growth effect and low-temperature continuous preparation. However, the present inventors have found through a large number of studies that the above patents do not pay attention to the fact that there is a difference between the lattice constants of graphene and the substrate material, which causes a certain degree of mismatch when the two form an interface. This not only affects the interface bonding strength, but also affects the free transfer of electrons at the interface due to the formation of mismatch dislocations at the interface, so that the graphene cannot fully play the role of super-high carrier mobility, and the conductivity of the graphene / copper composite wire is not improved.

[0005] Therefore, how to regulate the crystal structure characteristics of graphene in the graphene / copper composite wire without changing the existing CVD process, and how to improve the interface bonding and interface matching, have become the focus of current research. SUMMARY

[0006] The technical problem to be solved by the present application is to provide an amorphous carbon / copper composite wire and a preparation method thereof, which can regulate the crystal structure characteristics of graphene in the graphene / copper composite wire without changing the existing CVD process, and can improve the interface bonding and interface matching.

[0007] To solve the above problems, the application provides a preparation method of amorphous carbon / copper composite wire, comprising: providing a copper wire, performing surface treatment on the copper wire to make the surface roughness of the copper wire less than 5 nm, wherein the surface treatment comprises electrochemical polishing and annealing treatment; performing roll-to-roll chemical vapor deposition to grow graphene on the copper wire after the surface treatment; and inducing carbon atoms in the graphene to form pentagonal and heptagonal carbon rings by laser irradiation to construct an amorphous structure under ambient conditions, thereby obtaining the amorphous carbon / copper composite wire.

[0008] In an embodiment, the method of electrochemical polishing comprises: immersing the copper wire into a container containing an electrochemical polishing solution as an anode, and placing a copper sheet in the container as a cathode; the applied voltage is 1-20 V; the immersion time is 20-200 s; and the copper wire after immersion is cleaned to remove the electrochemical polishing solution and then dried.

[0009] In an embodiment, the electrochemical polishing solution is prepared from 500 mL of deionized water, 250 mL of ethanol, 250 mL of an acid solution, 50 mL of isopropyl alcohol and 5 g of urea; the acid solution is one of hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid or nitric acid, which is used to adjust the pH of the electrochemical polishing solution to 2-6.

[0010] In an embodiment, the annealing treatment further comprises: the annealing temperature is 600-1000 DEG C, the annealing time is 30-100 min, the flow rate of the reducing gas in the annealing atmosphere is 20-500 sccm, and the vacuum degree is 0.05-500 Torr.

[0011] In an embodiment, the step of performing roll-to-roll chemical vapor deposition to grow graphene on the copper wire after the surface treatment further comprises: cooling and winding the copper wire to obtain a graphene / copper composite wire, wherein the tension during winding is 50%-80% of the safe tension of the copper wire.

[0012] In an embodiment, the step of inducing carbon atoms in the graphene to form pentagonal and heptagonal carbon rings by laser irradiation further comprises: the laser power of laser irradiation is 1-75 W, the laser wavelength of laser irradiation is 10.6 μm, the pulse density of laser irradiation is 5-10 pluses / dot, the scanning speed of laser irradiation is 1-30 cm / s, and the irradiation time of laser irradiation is 1-20 min.

[0013] The embodiment of the application further provides an amorphous carbon / copper composite wire prepared by the above preparation method, which comprises a copper wire and amorphous carbon coated on the copper wire.

[0014] In one embodiment, the copper wire length of the amorphous carbon / copper composite wire is 1 m-500 m; the copper wire diameter is 100 μm-500 μm; the yield strength of the amorphous carbon / copper composite wire is 154.986 MPa, the yield strain is 1.38429 %, the tensile strength is 242.648 Mpa, and the tensile strain is 28.7833 %; and the signal intensity ratio at 1580 cm-1 and 1350 cm-1 on the Raman spectrum is greater than 3.5.

[0015] The amorphous carbon / copper composite wire and the preparation method thereof provided in the embodiment of the present application are prepared from the perspective of amorphization of graphene, and the laser irradiation is performed on the graphene / copper composite material prepared by the roll-to-roll chemical vapor deposition, so that the laser induces the carbon atoms in the graphene to form abundant pentagonal and heptagonal carbon rings, and the amorphous structure is constructed under the ambient conditions, thereby obtaining the amorphous carbon / copper composite wire. The composite wire prepared has high conductivity (>105 % IACS) and excellent mechanical strength. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0017] Figure 1 is a schematic diagram of the preparation method of the amorphous carbon / copper composite wire provided in one embodiment of the present application; Figure 2 is a partial schematic diagram of the roll-to-roll chemical vapor deposition equipment in the preparation method of the amorphous carbon / copper composite wire provided in one embodiment of the present application; Figure 3 is a partial schematic diagram of the laser irradiation equipment in the preparation method of the amorphous carbon / copper composite wire provided in one embodiment of the present application; Figure 4 is the optical microscope characterization of the amorphous carbon / copper composite wire prepared in the preparation method of the amorphous carbon / copper composite wire provided in one embodiment of the present application; Figure 5 is the SEM characterization of the amorphous carbon / copper composite wire prepared by the technical solution of the present application; Figure 6 is the Raman characterization of the amorphous carbon / copper composite wire prepared in the preparation method of the amorphous carbon / copper composite wire provided in one embodiment of the present application; Figure 7is a stress-strain diagram of the amorphous carbon / copper composite wire prepared by the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application. EMBODIMENT

[0018] The amorphous carbon / copper composite wire provided in the present application and the preparation method thereof will be described in detail in combination with the accompanying drawings.

[0019] Figure 1 is a schematic diagram of the steps of the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application, Figure 2 is a partial schematic diagram of a roll-to-roll chemical vapor deposition device in the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application, Figure 3 is a partial schematic diagram of a laser irradiation device in the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application, Figure 4 is optical microscope characterization of the amorphous carbon / copper composite wire prepared by the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application, Figure 5 is SEM characterization of the amorphous carbon / copper composite wire prepared by the technical solution of the present application, Figure 6 is Raman characterization of the amorphous carbon / copper composite wire prepared by the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application, Figure 7 is a stress-strain diagram of the amorphous carbon / copper composite wire prepared by the preparation method of the amorphous carbon / copper composite wire provided in an embodiment of the present application, please refer to Figures 1 to 7 , the preparation method comprising: Step S10, providing a copper wire, and performing surface treatment on the copper wire to make the surface roughness of the copper wire less than 5 nm, the surface treatment comprising electrochemical polishing and annealing treatment. The impurities and oxides on the surface of the copper wire are removed by electrochemical polishing, and the grain size of copper is increased by annealing treatment. After the copper wire is electrochemically polished to remove the surface impurities and oxides, the copper wire is transferred to a chemical vapor deposition furnace for annealing treatment.

[0020] In an embodiment, the length of the copper wire is 1-500 m, and the diameter is 100-500 μm.

[0021] In an embodiment, the method of electrochemical polishing comprises: immersing the copper wire into a container containing an electrochemical polishing solution as an anode, and placing a copper sheet in the container as a cathode; the external voltage is 1-20 V; the immersion time is 20-200 s; and the copper wire after immersion is cleaned to remove the electrochemical polishing solution and then dried. The cleaning to remove the electrochemical polishing solution and then drying comprises: using ionized water and alcohol to remove the electrochemical polishing solution, and then drying with nitrogen.

[0022] In an embodiment, the electrochemical polishing solution is prepared from 500 mL of deionized water, 250 mL of ethanol, 250 mL of an acid solution, 50 mL of isopropyl alcohol, and 5 g of urea; the acid solution is one of hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, or nitric acid, used to adjust the pH of the electrochemical polishing solution to 2-6. Further, the purity of the ethanol is 99.5%, the purity of the isopropyl alcohol is 99.9%, and the purity of the urea is 99%.

[0023] In an embodiment, the annealing process further includes: the annealing temperature is 600-1000 ℃, the annealing time is 30-100 min, the flow rate of the reducing gas in the annealing atmosphere is 20-500 sccm, and the vacuum degree is 0.05-500 Torr. Further, the reducing gas is H2. Specifically, the copper wire after electrochemical polishing is sent into a tubular furnace with a vacuum degree of 0.05-500 Torr, a flow rate of 20-500 sccm of the reducing gas, and a temperature rising rate of 2-10 ℃ / min to 600-1000 ℃ for annealing for 30-100 min.

[0024] In step S11, the copper wire after surface treatment is subjected to roll-to-roll chemical vapor deposition to grow graphene.

[0025] In this step, graphene is grown on the surface of the copper wire by roll-to-roll chemical vapor deposition. The growth process conditions are as follows: first, the chamber is pumped to an appropriate vacuum degree (0.01-0.1 Torr), then hydrogen gas is introduced to start temperature rising, and after the temperature reaches the growth temperature, carbon source gas and protective gas are introduced into the device to complete the growth of graphene. Specifically, at 800-1000 ℃, the flow rates of the carbon source, the reducing gas, and the protective gas are adjusted to 5-200 sccm, 100-500 sccm, and 50-200 sccm, respectively, the growth pressure is 0.05-800 Torr, and the holding time is 2-200 min, so as to grow graphene on the copper wire.

[0026] In an embodiment, the carbon source includes one or more of CH4, C2H6, C2H4, C2H2, and other alkane / alkyne / alkene gas carbon sources containing carbon; the reducing gas is H2; and the protective gas is Ar.

[0027] In an embodiment, when the carbon source is selected from CH3OH and C2H5OH, etc. carbon-containing alcohol liquid carbon sources, or glucose, polyethylene glycol, paraffin, stearic acid, and polymethyl methacrylate, etc. solid carbon sources, or solid-liquid mixed carbon sources, the carbon source needs to be heated and cracked into gaseous active carbon-containing groups before being sent into the reaction chamber, and the flow rate of the gaseous active carbon-containing groups is controlled to be 5-200 sccm.

[0028] The roll-to-roll chemical vapor deposition equipment used in this step is as shown in Figure 2 As shown in the figure, the copper wire 3 is arranged at the roll-to-roll input end 1 and the roll-to-roll output end 2 respectively, the carbon source gas 4, the protective gas 5 and the reducing gas 6 are input into the tube furnace 10, the heating wire 7 is arranged on the side wall of the tube furnace 10 in the graphene growth area 8, and the cooling water is arranged on one side of the roll-to-roll output end 2 for cooling after the graphene deposition.

[0029] Further, in a specific embodiment, the step of growing graphene on the surface-treated copper wire by roll-to-roll chemical vapor deposition further comprises: cooling and winding the copper wire to obtain a graphene / copper composite wire, wherein the tension during winding is 50%-80% of the safe tension of the copper wire. Further, the cooling speed of the cooling treatment is controlled at 5-40 ℃ / min. Further, the winding speed of the copper wire is 10-25 cm / min.

[0030] Specifically, after the obtained graphene / copper composite wire is wound on the winding shaft of the equipment, the gas inlet valve is closed, and the copper wire is gradually cooled to room temperature at a cooling rate of 5-40 ℃ / min; the tension during winding is 50%-80% of the safe tension of the copper wire obtained in step S11; the wire speed during winding is 10-25 cm / min.

[0031] In step S12, the carbon atoms in graphene are induced to form pentagonal and heptagonal carbon rings by laser irradiation to construct an amorphous structure under ambient conditions, and the amorphous carbon / copper composite wire is obtained. In this step, the crystalline graphene is converted into amorphous carbon (i.e. amorphous graphene), and the amorphous carbon forms a stronger coherent or semi-coherent interface with the copper matrix, which improves the interface bonding force; at the same time, the amorphous graphene itself has better toughness and ductility, so that the composite wire has good ductility.

[0032] Further, the laser power of the light irradiation is 1-75 W, the laser wavelength of the laser irradiation is 10.6 μm, the pulse density of the laser irradiation is 5-10 pluses / dot, the scanning speed of the laser irradiation is 1-30 cm / s, and the irradiation time of the laser irradiation is 1-20 min.

[0033] The laser irradiation equipment used in this step is as shown in Figure 3 The laser is emitted from the laser, reflected by the shutter, 1 / 2 wavelength filter assembly and multiple mirrors, and then incident on the objective lens, and then irradiated on the copper wire.

[0034] The present application also provides an amorphous carbon / copper composite wire prepared by the above-mentioned preparation method, which comprises a copper wire and amorphous carbon coated on the copper wire. The physical characterization of the amorphous carbon / copper composite wire is as shown in Figures 4 to 7 .

[0035] In an embodiment, the copper wire length of the amorphous carbon / copper composite wire is 1 m-500 m; the copper wire diameter is 100 μm-500 μm, the yield strength of the amorphous carbon / copper composite wire is 154.986 MPa, the yield strain is 1.38429 %, the tensile strength is 242.648 Mpa, the tensile strain is 28.7833 %, and the signal intensity ratio at 1580 cm -1 and 1350 cm -1 is greater than 3.5.

[0036] The technical solution provided by the present application is based on the fact that the lattice constants of graphene and copper wire are different, which causes a certain degree of mismatch when the two form an interface, which not only affects the interface bonding strength, but also affects the free transfer of electrons at the interface due to the formation of mismatch dislocations at the interface. Therefore, the Cu wire is electrochemically polished to a certain roughness, and a roll-to-roll chemical vapor deposition combined with laser irradiation is used to obtain an amorphous carbon / copper composite wire with high electrical conductivity (>105 % IACS) and excellent mechanical strength.

[0037] Specifically, the amorphous carbon / copper composite wire and the preparation method thereof provided by the present application have the following excellent effects: (1) The chemical vapor deposition (CVD) process parameters (deposition temperature, carbon source type, growth pressure, hydrogen partial pressure, etc.) in the technical solution provided by the present application have a further positive effect on the structure and performance of the graphene film coating on the surface of the copper wire with the selected roughness. The deposition temperature not only affects the decomposition of the carbon source, but also changes the solubility of carbon atoms in the rough copper matrix, thereby affecting the morphology and crystal structure characteristics of graphene; the reducing gas in chemical vapor deposition is hydrogen, which not only catalyzes the decomposition of the carbon source, but also etches the edges of the deposited graphene. By reasonably controlling the hydrogen partial pressure, the grain size of graphene is effectively controlled. In addition, the "invasion" effect of H2 on the carbon layer at the edge of graphene can etch the defect position of the doped graphene at the initial stage of deposition, thereby facilitating the growth of high-quality doped graphene. Therefore, by adjusting the deposition temperature, growth pressure, hydrogen partial pressure and other process parameters, high-quality, large-grain-size graphene film coating is prepared, and these parameters are essential conditions for obtaining an amorphous carbon / copper composite wire.

[0038] (2) Through the process in (1) above and combined with laser irradiation, the crystalline graphene is converted into amorphous graphene, and the amorphous carbon and the copper matrix form a stronger coherent or semi-coherent interface, so that the interface bonding force is improved; at the same time, the amorphous graphene itself has better toughness and ductility, so that the composite wire has good ductility. The yield strength of the amorphous carbon / copper composite wire prepared by the preparation method provided by the application is 154.986 MPa, the yield strain is 1.38429 %, the tensile strength is 242.5 MPa, and the tensile strain is 28.7833 %. On the basis of the strength comparable to pure copper, the plasticity is far superior to pure copper, and the core pain point of the traditional graphene / copper composite material "high strength and brittle" is successfully solved, which lays a solid foundation for its application in the field of flexible electronics.

[0039] (3) In addition, the conductivity of the amorphous carbon / copper composite wire provided by the application reaches 105 %IACS. After laser irradiation, the five-membered / seven-membered rings in the amorphous graphene form C-Cu covalent bonds (instead of weak van der Waals forces) with Cu atoms on the surface of copper, so that the interface between graphene and the copper substrate is well combined, the mutual transfer of free electrons at both ends of the interface is improved, and the effect of improving the conductivity is achieved, fully verifying the excellent improvement of amorphous treatment on the conductivity.

[0040] It should be noted that the terms "include" and "have" and their variants involved in the file of the application are intended to cover non-exclusive inclusion. The terms "first", "second" and the like are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, unless the context clearly indicates otherwise, and it should be understood that the data thus used can be interchanged under appropriate circumstances. The term "one or more" can be used to describe a feature, structure or characteristic in a singular sense, or can be used to describe a combination of features, structures or characteristics in a plural sense, depending at least partially on the context. The term "based on" can be understood as not necessarily expressing a set of exclusive factors, but can instead, depending at least partially on the context, allow the presence of other factors that are not necessarily explicitly described. In addition, the embodiments in the application and the features in the embodiments can be combined with each other without conflict. Furthermore, in the above description, the description of well-known components and technologies is omitted to avoid unnecessary confusion of the concepts of the application. In each of the above embodiments, each embodiment focuses on the difference from other embodiments, and the same / similar parts between the embodiments can be referred to each other.

[0041] The above is only the preferred embodiment of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered within the protection scope of the application.

Claims

1. A method for producing an amorphous carbon / copper composite wire, characterized by, The method comprises the following steps: providing a copper wire, performing surface treatment on the copper wire to make the surface roughness of the copper wire less than 5 nm, wherein the surface treatment comprises electrochemical polishing and annealing treatment; performing roll-to-roll chemical vapor deposition to grow graphene on the surface-treated copper wire; inducing carbon atoms in the graphene to form pentagonal and heptagonal carbon rings by laser irradiation to construct an amorphous structure under ambient conditions, thereby obtaining the amorphous carbon / copper composite wire.

2. The production method according to claim 1, characterized by, The method of electrochemical polishing comprises the following steps: immersing the copper wire into a container containing an electrochemical polishing solution as an anode, and placing a copper sheet in the container as a cathode; the applied voltage is 1-20 V; the immersion time is 20-200 s; and the copper wire is blown dry after cleaning to remove the electrochemical polishing solution.

3. The production method according to claim 2, characterized by, The electrochemical polishing solution is prepared by mixing 500 mL of deionized water, 250 mL of ethanol, 250 mL of an acid solution, 50 mL of isopropyl alcohol and 5 g of urea; the acid solution is one of hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid or nitric acid, which is used to adjust the pH of the electrochemical polishing solution to 2-6.

4. The method of claim 1, wherein, The annealing treatment further comprises the following steps: the annealing temperature is 600-1000 DEG C, the annealing time is 30-100 min, the flow rate of the reducing gas in the annealing atmosphere is 20-500 sccm, and the vacuum degree is 0.05-500 Torr.

5. The preparation method according to claim 1, characterized in that, The step of performing roll-to-roll chemical vapor deposition to grow graphene on the surface-treated copper wire further comprises the following steps: cooling and winding the copper wire to obtain a graphene / copper composite wire, wherein the tension during winding is 50%-80% of the safe tension of the copper wire.

6. The method of claim 1, wherein, The step of inducing carbon atoms in the graphene to form pentagonal and heptagonal carbon rings by laser irradiation further comprises the following steps: the laser power of laser irradiation is 1-75 W, the laser wavelength of laser irradiation is 10.6 μm, the pulse density of laser irradiation is 5-10 pluses / dot, the scanning speed of laser irradiation is 1-30 cm / s, and the irradiation time of laser irradiation is 1-20 min.

7. An amorphous carbon / copper composite wire, characterized by, The amorphous carbon / copper composite wire is prepared by the method according to any one of claims 1-6, and comprises a copper wire and amorphous carbon coated on the copper wire.

8. The amorphous carbon / copper composite wire of claim 7, wherein, The length of the copper wire of the amorphous carbon / copper composite wire is 1 m-500 m; the diameter of the copper wire is 100 μm-500 μm; the yield strength of the amorphous carbon / copper composite wire is 154.986 MPa, the yield strain is 1.38429 %, the tensile strength is 242.648 Mpa, the tensile strain is 28.7833 %, and the signal intensity ratio at 1580 cm -1 and 1350 cm -1 in the Raman spectrum is greater than 3.5.

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