Interface regulation and control method of graphene copper composite material

Abstract

The invention discloses an interface regulation and control method for a graphene-copper composite material, relates to the technical field of metal-based composite material preparation, and aims to solve the problem of how to improve weak electron exchange between graphene and copper. The interface regulation and control method comprises the following steps: S1, raw material selection; a commercially available Gr / Cu / Gr foil is selected as a substrate, and high-purity metal particles are selected as an evaporation target material; s2, depositing metal; depositing heterogeneous metal layers with different thicknesses on the two surfaces of the substrate by using a vacuum thermal evaporation coating process to obtain the substrate wrapped by the heterogeneous metal layers; s3, metal deposition pretreatment; s2, performing thermal annealing treatment on the matrix obtained in the step S2 to obtain a heterogeneous metal coating with high crystallinity; and S4, stacking a plurality of substrates treated in the step S3 to construct an interface structure beneficial to electric conduction, and then preparing the high-electric-conductivity graphene copper block material through a vacuum hot press molding process.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of metal-based composite materials, and in particular to an interface control method of a graphene-copper composite material. Background Art

[0002] Copper-based composite materials are widely used in electronic products, aerospace and traditional industrial fields due to their excellent electrical and thermal conductivity and good processing performance. In recent years, as the research on graphene has been further extended, its various unique physical properties have been discovered.

[0003] Due to the high strength and high carrier migration speed of graphene, it is expected to become a reinforcement for copper-based composite materials, further improving the conductivity of copper-based composite materials and breaking through the conductivity limit of traditional copper-based materials. Ultra-high conductive copper refers to copper-based composite materials with a conductivity exceeding 100% IACS. It has promoted the development of electronics and energy fields.

[0004] At present, there are two main methods to control the interface structure of graphene-copper composite materials. First, through the SPS process, the content of impurities such as oxygen in the interface between graphene and copper is reduced to improve the cleanliness of the interface. Second, through the powder metallurgy process, metal powder with good bonding performance with graphene is mixed, and the bulk material is prepared through the hot pressing sintering process. The added metal can effectively strengthen the bonding between graphene and copper and promote electron exchange.

[0005] Although the above two methods can play a role in improving the conductivity, they can no longer guarantee a continuous conductive channel and promote electron exchange. Summary of the invention

[0006] The present invention provides a method for controlling the interface of a graphene copper composite material, which comprises the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate and high-purity metal particles as the evaporation target; S2: depositing metal; depositing heterogeneous metal layers of different thicknesses on both sides of the substrate by a vacuum thermal evaporation coating process to obtain the substrate wrapped by the heterogeneous metal layers; S3: Pretreatment of deposited metal: thermal annealing the substrate obtained in step S2 to obtain a heterogeneous metal coating with high crystallinity; S4: stacking a plurality of substrates processed in step S3 to construct an interface structure conducive to electrical conductivity, and then preparing a highly conductive graphene copper block material through a vacuum hot pressing process.

[0007] The present invention is further configured as follows: in the thermal evaporation coating process in step S2, the vacuum degree is controlled at ≤1×10 -5Pa, the evaporation rate is controlled at 0.1nm / s.

[0008] The present invention is further configured as follows: in step S2, the thickness of the heterogeneous metal layer is controlled to be 20-100 nm.

[0009] The present invention is further configured as follows: the thermal annealing treatment in step S3 is carried out in a heat treatment furnace, and an argon atmosphere is maintained in the heat treatment furnace; for heterogeneous metals with a melting point higher than copper, the annealing temperature is controlled at 783-983°C; for heterogeneous metals with a melting point lower than copper, the annealing temperature is controlled at 883-983°C; and the annealing time is controlled at 30-150min.

[0010] The present invention is further configured as follows: in the vacuum hot pressing forming process in step S4, the vacuum degree is controlled at ≤1×10 -4 Pa; the hot pressing pressure is controlled at 50MPa, the hot pressing temperature is controlled at 1000℃, the heat preservation time is 60min, and the pressure holding time is 60min.

[0011] The present invention also provides a method for controlling the interface of a graphene copper composite material, which comprises the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr / foil as the substrate and high-purity metal particles as the evaporation target; S2: depositing metal; depositing heterogeneous metal layers of different thicknesses on both sides of the substrate using an electron beam evaporation coating process to obtain a substrate wrapped by the heterogeneous metal layers; S3: Pretreatment of deposited metal: performing thermal annealing on the substrate obtained in step S2 to obtain a heterogeneous metal coating with high crystallinity; S4: stacking a plurality of substrates processed in step S3 to construct an interface structure conducive to electrical conductivity, and then preparing a highly conductive graphene copper bulk material through a vacuum hot pressing process.

[0012] The present invention is further configured as follows: in the electron beam evaporation process in step S2, the vacuum degree is controlled at ≤1×10 - 5 Pa, the fixed evaporation rate is 0.1nm / s, the evaporation distance is 50cm, the electron gun voltage is 10KV, and the substrate temperature is 25℃.

[0013] The present invention is further configured as follows: in step S2, the thickness of the heterogeneous metal layer is controlled to be 20-100 nm.

[0014] The present invention is further configured as follows: the thermal annealing treatment in step S3 is carried out in a heat treatment furnace, and an argon atmosphere is maintained in the heat treatment furnace; for heterogeneous metals with a melting point higher than copper, the annealing temperature is controlled at 783-983°C; for heterogeneous metals with a melting point lower than copper, the annealing temperature is controlled at 883-983°C; and the annealing time is controlled at 30-150min.

[0015] The present invention is further configured as follows: in the vacuum hot pressing forming process in step S4, the vacuum degree is controlled at 1×10 -4 Pa; the hot pressing pressure is controlled at 50MPa, the hot pressing temperature is controlled at 1000℃, the heat preservation time is 60min, and the pressure holding time is 60min.

[0016] The beneficial effects of the present invention are as follows: the process flow adopted by the present invention can ensure the continuous distribution of heterogeneous atomic layers, and driven by the difference in work function, the charge of the interface auxiliary components is redistributed to form an interface dipole, change the energy band structure of the material, form a new electronic transition path, construct a new conductive channel, and improve the conductivity of the composite material. At present, the conductivity of the composite material prepared by using this method can reach 118.4% IACS. This means that the weight and volume of the wire can be reduced under the same conductivity requirements, which can promote the lightweight process of the wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A process flow chart of Example 1 is shown.

[0018] Figure 2 The conductivity using different evaporation target materials is shown.

[0019] Figure 3 The conductivity of metal layers deposited with different thicknesses is shown.

[0020] Figure 4 The Raman spectrum of graphene after silver coating is shown.

[0021] Figure 5 The Raman spectrum of unsilvered graphene is shown.

[0022] Figure 6 A process flow diagram for Example 8 is shown. DETAILED DESCRIPTION

[0023] Those skilled in the art can refer to the content of this article and appropriately improve the process parameters. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0024] Example 1

[0025] The present invention provides a method for controlling the interface of a graphene copper composite material, comprising the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate and high-purity metal particles as the evaporation target; S2: depositing metal; depositing heterogeneous metal layers of different thicknesses on both sides of the substrate by a vacuum evaporation coating process to obtain the substrate wrapped by the heterogeneous metal layers; S3: Pretreatment of deposited metal: thermal annealing the substrate obtained in step S2 to obtain a heterogeneous metal coating with high crystallinity; S4: stacking a plurality of substrates processed in step S3 to construct an interface structure conducive to electrical conductivity, and then preparing a highly conductive graphene copper block material through a vacuum hot pressing process.

[0026] The vacuum degree of the thermal evaporation coating process in step S2 is controlled at ≤1×10 -5 Pa, the evaporation rate is controlled at 0.1nm / s, and the thickness of the heterogeneous metal layer is controlled at 20-100nm.

[0027] The thermal annealing treatment in step S3 is carried out in a heat treatment furnace, and an argon atmosphere is maintained in the heat treatment furnace; for heterogeneous metals with a melting point higher than copper, the annealing temperature is controlled at 783-983°C, that is, the melting point of copper is 1083°C, and the annealing temperature is controlled at 100-300°C below the melting point of copper; for heterogeneous metals with a melting point lower than copper, the annealing temperature is controlled at 883-983°C, that is, the annealing temperature is controlled at 100-200°C below the melting point of copper; the annealing time is controlled at 30-150min.

[0028] The vacuum hot pressing process in step S4 is controlled at a vacuum degree of 1×10 -4 Pa; the hot pressing pressure is controlled at 50MPa, the hot pressing temperature is controlled at 1000℃, the heat preservation time is 60min, and the pressure holding time is 60min.

[0029] It should be noted that the evaporation target materials described in step S1 are mainly divided into three categories, the first being magnetic metals such as nickel and cobalt, the second being physically adsorbed metals such as silver and aluminum, and the third being chemically adsorbed metals such as titanium and chromium.

[0030] It should also be noted that the interface structure after stacking in step S4 is Cu / Gr / M / Gr / Cu, wherein M represents the deposited heterogeneous metal coating.

[0031] Example 2

[0032] This embodiment adopts the method disclosed in Example 1 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and silver particles with a purity of 99.99% are selected as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait for the vacuum degree of the thermal evaporation system to drop to 1×10 -5 Pa started coating, with a fixed evaporation rate of 0.1nm / s. A 20nm silver layer was slowly deposited on both surfaces of the substrate to obtain a substrate covered with a silver layer. The silver-plated substrate was characterized, such as Figure 4 , 5 As shown, the Raman spectrum of graphene after silver coating shows a tendency of blue shift of G peak and red shift of 2D peak compared with that of graphene without silver coating, indicating that graphene is doped with electrons and electrons are transmitted through the conductive path of graphene. S3: Pretreatment of deposited metal; put the substrate wrapped with the silver layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and a silver coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling. S4: Stack multiple silver-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and perform a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 116.6% IACS and a size of 2cm×2cm×0.5cm.

[0033] Example 3

[0034] This embodiment adopts the method disclosed in Example 1 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and silver particles with a purity of 99.99% are selected as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait for the vacuum degree of the thermal evaporation system to drop to 1×10 -5 Pa, the coating was started with a fixed evaporation rate of 0.1 nm / s. A 40 nm silver layer was slowly deposited on both surfaces of the substrate to obtain a substrate covered with a silver layer. S3: Pretreatment of deposited metal; put the substrate wrapped with the silver layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 600℃, the holding time to 60min, and then cool, and a silver coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling. S4: Stack multiple silver-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and perform a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 118.4% IACS and a size of 2cm×2cm×0.5cm.

[0035] Example 4

[0036] This embodiment adopts the method disclosed in Example 1 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and silver particles with a purity of 99.99% are selected as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait for the vacuum degree of the thermal evaporation system to drop to 1×10 -5 Pa, the coating was started with a fixed evaporation rate of 0.1 nm / s. A 100 nm silver layer was slowly deposited on both surfaces of the substrate to obtain a substrate covered with a silver layer. S3: Pretreatment of deposited metal; put the substrate wrapped with the silver layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 600℃, the holding time to 60min, and then cool, and a silver coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling.

[0037] S4: Stack multiple silver-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and perform a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 114.32% IACS and a size of 2cm×2cm×0.5cm.

[0038] Example 5

[0039] This embodiment adopts the method disclosed in Example 1 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and select chromium particles with a purity of 99.99% as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait for the vacuum degree of the thermal evaporation system to drop to 1×10 -5 Pa, the film coating was started with a fixed evaporation rate of 0.1 nm / s. A 20 nm chromium layer was slowly deposited on both surfaces of the substrate to obtain a substrate covered with a chromium layer. S3: Pretreatment of deposited metal; put the substrate wrapped by the chromium layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and obtain a chromium plating layer with high crystallinity after cooling. The cooling method is furnace cooling.

[0040] S4: Stack multiple chromium-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and conduct a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 113.8% IACS and a size of 2cm×2cm×0.5cm.

[0041] Example 6

[0042] This embodiment adopts the method disclosed in Example 1 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and select nickel particles with a purity of 99.99% as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait for the vacuum degree of the thermal evaporation system to drop to 1×10 -5 Pa, the film coating was started with a fixed evaporation rate of 0.1 nm / s. A 20 nm nickel layer was slowly deposited on both surfaces of the substrate to obtain a substrate covered with a nickel layer. S3: Pretreatment of deposited metal; put the substrate wrapped by the nickel layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and a nickel coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling.

[0043] S4: Stack multiple nickel-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and conduct a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 112.4% IACS and a size of 2cm×2cm×0.5cm.

[0044] Example 7

[0045] This embodiment adopts the method disclosed in Example 1 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and select aluminum particles with a purity of 99.99% as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait for the vacuum degree of the thermal evaporation system to drop to 1×10 -5 Pa, the film coating was started with a fixed evaporation rate of 0.1 nm / s. A 20 nm thick aluminum layer was slowly deposited on both surfaces of the substrate to obtain a substrate wrapped by the aluminum layer. S3: Pretreatment of deposited metal; put the substrate wrapped by the aluminum layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 600℃, the holding time to 60min, and then cool, and obtain an aluminum coating with high crystallinity after cooling. The cooling method is furnace cooling. S4: Stack multiple aluminum-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and conduct a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 114.5% IACS and a size of 2cm×2cm×0.5cm.

[0046] Example 8

[0047] The present invention also proposes a method for controlling the interface of a graphene copper composite material, comprising the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate and high-purity metal particles as the evaporation target; S2: depositing metal; depositing heterogeneous metal layers of different thicknesses on both sides of the substrate by electron beam evaporation coating process to obtain a substrate wrapped with heterogeneous metal layers; S3: Pretreatment of deposited metal: performing thermal annealing on the substrate obtained in step S2 to obtain a heterogeneous metal coating with high crystallinity; S4: stacking a plurality of substrates processed in step S3 to construct an interface structure conducive to electrical conductivity, and then performing a vacuum hot pressing process to obtain a highly conductive graphene copper block material.

[0048] In the electron beam evaporation process in step S2, the vacuum degree is controlled at ≤1×10 -5Pa, fixed evaporation rate of 0.1 nm / s, evaporation distance of 50 cm, electron gun voltage of 10 KV, substrate temperature of 35 ° C. The thickness of the heterogeneous metal layer is controlled at 20-100 nm.

[0049] The thermal annealing treatment in step S3 is carried out in a heat treatment furnace, and an argon atmosphere is maintained in the heat treatment furnace; for heterogeneous metals with a melting point higher than copper, the annealing temperature is controlled at 783-983°C, that is, the melting point of copper is 1083°C, and the annealing temperature is controlled at 100-300°C below the melting point of copper; for heterogeneous metals with a melting point lower than copper, the annealing temperature is controlled at 883-983°C, that is, the annealing temperature is controlled at 100-200°C below the melting point of copper; the annealing time is controlled at 30-150min.

[0050] The vacuum hot pressing process in step S4 is controlled at a vacuum degree of 1×10 -4 Pa; the hot pressing pressure is controlled at 50MPa, the hot pressing temperature is controlled at 1000℃, the heat preservation time is 60min, and the pressure holding time is 60min.

[0051] It should be noted that the evaporation target materials described in step S1 are mainly divided into three categories, the first being magnetic metals such as nickel and cobalt, the second being physically adsorbed metals such as silver and aluminum, and the third being chemically adsorbed metals such as titanium and chromium.

[0052] It should also be noted that the interface structure after stacking in step S4 is Cu / Gr / M / Gr / Cu, wherein M represents the deposited heterogeneous metal coating.

[0053] Example 9

[0054] This embodiment adopts the method disclosed in Example 8 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and silver particles with a purity of 99.99% are selected as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait until the vacuum degree of the electron beam evaporation system reaches 1×10 -5 Pa, the evaporation rate was fixed at 0.1nm / s, the evaporation distance was 50cm, the electron gun voltage was 10KV, and the substrate temperature was 25℃. A 20nm silver layer was slowly deposited on both surfaces of the substrate to obtain a substrate wrapped in a silver layer. The silver-plated substrate was characterized, such as Figure 4 , 5 As shown, the Raman spectrum of graphene after silver coating shows a tendency of blue shift of G peak and red shift of 2D peak compared with that of graphene without silver coating, indicating that graphene is doped with electrons and electrons are transmitted through the conductive path of graphene. S3: Pretreatment of deposited metal; put the substrate wrapped with the silver layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and a silver coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling.

[0055] S4: Stack multiple silver-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and perform a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 116.6% IACS and a size of 2cm×2cm×0.5cm.

[0056] Example 10

[0057] This embodiment adopts the method disclosed in Example 8 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and silver particles with a purity of 99.99% are selected as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait until the vacuum degree of the electron beam evaporation system reaches 1×10 -5 Pa, the evaporation rate was fixed at 0.1 nm / s, the evaporation distance was 50 cm, the electron gun voltage was 10 KV, and the substrate temperature was 25 ° C. A 40 nm silver layer was slowly deposited on both surfaces of the substrate to obtain a substrate wrapped by the silver layer. S3: Pretreatment of deposited metal; put the substrate wrapped with the silver layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and a silver coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling.

[0058] S4: Stack multiple silver-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and perform a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 118.4% IACS and a size of 2cm×2cm×0.5cm.

[0059] Embodiment 11

[0060] This embodiment adopts the method disclosed in Example 8 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and silver particles with a purity of 99.99% are selected as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait until the vacuum degree of the electron beam evaporation system reaches 1×10 -5 Pa started coating, with a fixed evaporation rate of 0.1 nm / s, an evaporation distance of 50 cm, an electron gun voltage of 10 KV, and a substrate temperature of 25 ° C. A 100 nm silver layer was slowly deposited on both surfaces of the substrate to obtain a substrate wrapped by the silver layer. S3: Pretreatment of deposited metal; put the substrate wrapped with the silver layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and a silver coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling.

[0061] S4: Stack multiple silver-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and perform a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 114.32% IACS and a size of 2cm×2cm×0.5cm.

[0062] Example 12

[0063] This embodiment adopts the method disclosed in Example 8 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and select chromium particles with a purity of 99.99% as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait until the vacuum degree of the electron beam evaporation system reaches 1×10 -5 Pa started coating, with a fixed evaporation rate of 0.1 nm / s, an evaporation distance of 50 cm, an electron gun voltage of 10 KV, and a substrate temperature of 25 ° C. A 20 nm chromium layer was slowly deposited on both surfaces of the substrate to obtain a substrate covered with a chromium layer; S3: Pretreatment of deposited metal; put the substrate wrapped by the chromium layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and obtain a chromium plating layer with high crystallinity after cooling. The cooling method is furnace cooling.

[0064] S4: Stack multiple chromium-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and conduct a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 113.8% IACS and a size of 2cm×2cm×0.5cm.

[0065] Embodiment 13

[0066] This embodiment adopts the method disclosed in Example 8 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and select nickel particles with a purity of 99.99% as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait until the vacuum degree of the electron beam evaporation system reaches 1×10 -5 Pa started coating, with a fixed evaporation rate of 0.1 nm / s, an evaporation distance of 50 cm, an electron gun voltage of 10 KV, and a substrate temperature of 25 ° C. A 20 nm nickel layer was slowly deposited on both surfaces of the substrate to obtain a substrate wrapped by the nickel layer; S3: Pretreatment of deposited metal; put the substrate wrapped by the chromium layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and a nickel coating with high crystallinity is obtained after cooling. The cooling method is furnace cooling.

[0067] S4: Stack multiple nickel-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and conduct a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 112.4% IACS and a size of 2cm×2cm×0.5cm.

[0068] Embodiment 14

[0069] This embodiment adopts the method disclosed in Example 8 to regulate the interface of the graphene copper composite material, which specifically includes the following steps: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate, the selected foil thickness is 25 μm, and select aluminum particles with a purity of 99.99% as the evaporation target; S2: Deposit metal; fix the substrate selected in step S1 above the evaporation source, and wait until the vacuum degree of the electron beam evaporation system reaches 1×10 -5 Pa, the evaporation rate was fixed at 0.1 nm / s, the evaporation distance was 50 cm, the electron gun voltage was 10 KV, and the substrate temperature was 25 ° C. A 20 nm aluminum layer was slowly deposited on both surfaces of the substrate to obtain a substrate wrapped by the aluminum layer. S3: Pretreatment of deposited metal; put the substrate wrapped by the aluminum layer obtained in step S2 into a heat treatment furnace, evacuate to below 1Pa, then introduce argon gas, and continue evacuating until the heat treatment furnace reaches atmospheric pressure, repeat several times to ensure that the heat treatment furnace is in an oxygen-free environment, that is, to achieve the purpose of washing the heat treatment furnace, set the heating rate to 15℃ / min, the holding temperature to 800℃, the holding time to 60min, and then cool, and obtain an aluminum coating with high crystallinity after cooling. The cooling method is furnace cooling.

[0070] S4: Stack multiple aluminum-wrapped substrates and put them into a graphite mold of a hot pressing furnace. Set the heating rate to 15°C / min, the hot pressing temperature to 1000°C, the holding time to 60min, the pressing time and the heating time to be carried out simultaneously, the hot pressing pressure to 50MPa, and the holding time to 60min. After cooling to room temperature with the furnace, take samples and grind off the surface graphite, and conduct a Van der Pauw conductivity test to obtain a copper sheet with a conductivity of 114.5% IACS and a size of 2cm×2cm×0.5cm.

[0071] In summary, the process flow adopted by the present invention can ensure the continuous distribution of heterogeneous atomic layers, and driven by the difference in work function, the charge of the interface auxiliary components is redistributed to form an interface dipole, change the energy band structure of the material, form a new electronic transition path, construct a new conductive channel, and improve the conductivity of the composite material. At present, the conductivity of the composite material prepared by this method can reach 118.4% IACS. This means that the weight and volume of the wire can be reduced under the same conductivity requirements, which can promote the lightweight process of the wire.

[0072] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be within the scope of protection of the present invention.

Claims

1. A method for controlling the interface of a graphene copper composite material, characterized in that: The following steps are involved: S1: Raw material selection: select commercially available Gr / Cu / Gr foil as the substrate and high-purity metal particles as the evaporation target; S2: depositing metal; depositing heterogeneous metal layers of different thicknesses on both sides of the substrate by a vacuum thermal evaporation coating process to obtain the substrate wrapped by the heterogeneous metal layers; S3: Pretreatment of deposited metal: thermal annealing the substrate obtained in step S2 to obtain a heterogeneous metal coating with high crystallinity; S4: stacking a plurality of substrates processed in step S3 to construct an interface structure conducive to electrical conductivity, and then preparing a highly conductive graphene copper block material through a vacuum hot pressing process.

2. The method for controlling the interface of the graphene copper composite material according to claim 1, characterized in that: The vacuum degree of the thermal evaporation coating process in step S2 is controlled at ≤1×10 -5 Pa, the evaporation rate is controlled at 0.1nm / s.

3. A method for controlling the interface of a graphene copper composite material, characterized in that: The following steps are involved: S1: Raw material selection: select commercially available Gr / Cu / Gr / foil as the substrate and high-purity metal particles as the evaporation target; S2: depositing metal; depositing heterogeneous metal layers of different thicknesses on both sides of the substrate using an electron beam evaporation coating process to obtain a substrate wrapped by the heterogeneous metal layers; S3: Pretreatment of deposited metal: performing thermal annealing on the substrate obtained in step S2 to obtain a heterogeneous metal coating with high crystallinity; S4: stacking a plurality of substrates processed in step S3 to construct an interface structure conducive to electrical conductivity, and then preparing a highly conductive graphene copper bulk material through a vacuum hot pressing process.

4. The method for controlling the interface of the graphene copper composite material according to claim 3, characterized in that: In the electron beam evaporation process in step S2, the vacuum degree is controlled at ≤1×10 -5 Pa, the fixed evaporation rate is 0.1nm / s, the evaporation distance is 50cm, the electron gun voltage is 10KV, and the substrate temperature is 25℃.

5. The method for controlling the interface of the graphene copper composite material according to claim 2 or 4, characterized in that: In step S2, the thickness of the heterogeneous metal layer is controlled to be 20-100 nm.

6. The method for controlling the interface of the graphene copper composite material according to claim 1 or 3, characterized in that: The thermal annealing treatment in step S3 is carried out in a heat treatment furnace, and an argon atmosphere is maintained in the heat treatment furnace; for heterogeneous metals with a melting point higher than copper, the annealing temperature is controlled at 783-983°C; for heterogeneous metals with a melting point lower than copper, the annealing temperature is controlled at 883-983°C; and the annealing time is controlled at 30-150 min.

7. The method for controlling the interface of the graphene copper composite material according to claim 1 or 3, characterized in that: In the vacuum hot pressing process in step S4, the vacuum degree is controlled at 1×10 -4 Pa; the hot pressing pressure is controlled at 50MPa, the hot pressing temperature is controlled at 1000℃, the heat preservation time is 60min, and the pressure holding time is 60min.

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