A method for preparing a graphene-metal composite layer

Abstract

The application provides a preparation method of a graphene-metal composite layer, which comprises the following steps: preparing graphene oxide and partially reducing the graphene oxide; mixing the obtained partially reduced graphene oxide, an additive and a magnetic oxide in a solvent to prepare a partially reduced graphene oxide-magnetic oxide composite; and adding the partially reduced graphene oxide-magnetic oxide composite into an electroplating base solution containing metal ions, so that the graphene oxide-magnetic oxide composite can be uniformly distributed in the electroplating solution and can adsorb the metal ions; after electroplating under electricity, under the joint action of an electric field and a magnetic field, the metal ions are reduced into metal elements and deposited on the surface of a plating object to form a metal plating layer, and the partially reduced graphene oxide-magnetic oxide composite is embedded in the metal plating layer; in subsequent hot-pressing sintering, the partially reduced graphene oxide can be reduced and the magnetic oxide can be reduced, so that an electric contact conductor material containing a graphene-metal composite layer is obtained, and the conductivity, wear resistance, corrosion resistance and anti-welding property of the electric contact conductor material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical contact conductor, in particular to a preparation method of graphene-metal composite layer. BACKGROUND

[0002] Graphene has many advantages, such as high electrical conductivity, high thermal conductivity, high strength, high flexibility, strong chemical inertness, and excellent gas barrier performance, which makes graphene have great application prospects in many aspects.

[0003] In the technical field of electrical contact conductor, graphene is applied to electrical contact conductor material. The existing method mainly uses powder pressing or electroplating method to improve the electrical conductivity, corrosion resistance, welding resistance or wear resistance of the electrical contact conductor material. The powder pressing process includes depositing a graphene layer on the surface of metal powder by vapor deposition, and then hot extruding the metal powder into an electrical contact conductor. The formed electrical contact conductor contains graphene. The electroplating process includes mixing metal ions and graphene into the same plating solution for electroplating, so that graphene and metal are mixed together to form on the surface of the electrical contact conductor. For example, the prior art discloses a graphene dispersion device and a graphene electroplating solution dispersion device. The graphene dispersion device includes a main container for storing graphene dispersion liquid and a circulating and dispersing structure for circulating and dispersing the graphene dispersion liquid. The inlet and outlet of the circulating and dispersing structure are respectively communicated with the main container. The graphene dispersion liquid in the main container of the graphene dispersion device can maintain a uniform and stable dispersion state for a long time. Further, the graphene electroplating solution dispersion device including the graphene dispersion device is beneficial to improve the quality of electroplated products.

[0004] However, although the electroplating method has realized the application of graphene in the field of electrical contact conductor, when different single types of metal are electroplated on the surface of the electrical contact conductor, different suitable dispersants need to be replaced to cooperate with the electroplating solution. The selection of dispersants is still a big problem in realizing the application of graphene in the field of electrical contact conductor by electroplating method. In the field of electroplating, it is still a big problem to realize the application of graphene and composite material in the field of electrical contact conductor by electroplating method, which involves not only the dispersion of graphene, but also the migration and reduction of different metals. So far, there are relatively few disclosed technical solutions about the formation of composite graphene electrical contact conductor material by mixing graphene with different metals through electroplating method, and even fewer can be industrialized.

[0005] In summary, there is a need to develop a new preparation method of graphene-metal composite layer. SUMMARY

[0006] In view of the problems in the prior art, the present application provides a preparation method of a graphene-metal composite layer, which comprises the following steps: preparing graphene oxide and partially reducing the graphene oxide to obtain partially reduced graphene oxide; mixing the partially reduced graphene oxide, an additive and a magnetic oxide in a solvent to obtain a partially reduced graphene oxide-magnetic oxide composite; and adding the partially reduced graphene oxide-magnetic oxide composite into an electroplating base solution containing metal ions, taking a plating piece as a cathode or connecting the plating piece with a cathode, and forming a magnetic field around the plating piece to obtain a partially reduced graphene oxide-metal composite layer through electroplating.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] The present application aims to provide a preparation method of a graphene-metal composite layer, which comprises the following steps:

[0009] Preparation of graphene oxide and partial reduction of the graphene oxide to obtain partially reduced graphene oxide;

[0010] Mixing the partially reduced graphene oxide, an additive and a magnetic oxide in a solvent to obtain a partially reduced graphene oxide-magnetic oxide composite;

[0011] Adding the partially reduced graphene oxide-magnetic oxide composite into an electroplating base solution containing metal ions, taking a plating piece as a cathode or connecting the plating piece with a cathode, and forming a magnetic field around the plating piece to obtain a partially reduced graphene oxide-metal composite layer through electroplating.

[0012] Washing, drying and hot-pressing sintering to obtain a graphene-metal composite layer.

[0013] As a preferred technical solution of the present application, the additive is sodium citrate.

[0014] As a preferred technical solution of the present application, graphene oxide is prepared and mixed with a solvent to obtain a mixed system, sodium citrate is added for partial reduction, and a magnetic oxide is added into the mixed system containing partially reduced graphene oxide and sodium citrate for mixing reaction to obtain a partially reduced graphene oxide-magnetic oxide composite.

[0015] As a preferred technical solution of the present application, the initial mass ratio of the graphene oxide, sodium citrate and magnetic oxide is controlled to be 1:(8-10):(0.4-0.6).

[0016] As a preferred technical scheme of the present application, the concentration of graphene oxide in the mixed system is 0.25-0.35 g / L before adding sodium citrate, and the temperature of the mixed system is 80-100℃.

[0017] As a preferred technical scheme of the present application, the time for partial reduction is 5-6 h.

[0018] As a preferred technical scheme of the present application, the solvent comprises water.

[0019] As a preferred technical scheme of the present application, the magnetic oxide comprises any one or a combination of any two or three of nickel oxide, triiron tetroxide or cobalt oxide.

[0020] As a preferred technical scheme of the present application, the mass concentration of the partially reduced graphene oxide-magnetic oxide composite in the electroplating solution is controlled to be 1.5-3 g / L.

[0021] As a preferred technical scheme of the present application, the electroplating base solution containing metal ions comprises any one of a copper electroplating base solution, a copper-tin electroplating base solution, a silver electroplating base solution or a nickel electroplating base solution.

[0022] As a preferred technical scheme of the present application, a coil is wound around the cathode to form a magnetic field around the part to be plated in an electro-magnetic manner.

[0023] As a preferred technical scheme of the present application, the number of turns of the coil is 15-1000 turns.

[0024] As a preferred technical scheme of the present application, the drying is vacuum drying, the temperature of the vacuum drying is 100-150℃, and the time of the vacuum drying is 20-35 min.

[0025] As a preferred technical scheme of the present application, the temperature of the hot-press sintering is 800-1000℃, and the holding time of the hot-press sintering is 35-40 min.

[0026] As a preferred technical scheme of the present application, the temperature of the hot-press sintering is below 450℃, and the heating rate is controlled to be 7-9℃ / min; the temperature of the hot-press sintering is above 450℃, and the heating rate is controlled to be 14-16℃ / min.

[0027] As a preferred technical scheme of the present application, the hot-press sintering is pressurized by hydrogen and / or methane, and the pressure of the hot-press sintering is controlled to be 25-35 MPa.

[0028] Compared with the prior art, the present application has at least the following beneficial effects:

[0029] (1) The preparation method of the present invention uses partially reduced graphene oxide with better dispersibility to replace graphene, and uses an auxiliary agent to establish an oxygen bridge between the partially reduced graphene oxide and the magnetic oxide to form a partially reduced graphene oxide-magnetic oxide composite, so that the partially reduced graphene oxide-magnetic oxide composite is not only extremely dispersible in water, but also magnetic due to the composite with the magnetic oxide. The partially reduced graphene oxide-magnetic oxide composite is not only uniformly dispersed in the solution, but also adsorbs metal ions. After electroplating, under the combined action of the electric field and the magnetic field, the partially reduced graphene oxide-magnetic oxide composite and the metal ions move toward the cathode together, thereby obtaining an electrical contact conductor material containing a graphene-metal composite layer, which not only improves conductivity, but also improves wear resistance, corrosion resistance and welding resistance;

[0030] (2) The preparation method of the present invention can be applied not only to the electroplating of silver, nickel, copper, etc., but also to the composite electroplating of copper-nickel, copper-silver, copper-tin, etc., which can greatly reduce the use of dispersants or eliminate the use of dispersants, thereby reducing the toxicity of the plating solution due to the addition of dispersants, and solving the difficult problem of finding different dispersants to adapt to different metal ion plating solutions in electroplating. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of a winding coil in the method for preparing a graphene-metal composite layer of the present invention;

[0032] In the figure: 1-electroplating tank; 2-power supply device; 3-anode; 4-cathode; 5-coil; 6-hanging rack; 7-parts to be plated. DETAILED DESCRIPTION

[0033] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0034] The present invention provides a method for preparing a graphene-metal composite layer, the preparation method comprising the following steps:

[0035] preparing graphene oxide and partially reducing it to obtain partially reduced graphene oxide;

[0036] The partially reduced graphene oxide, the auxiliary agent and the magnetic oxide are mixed and reacted in a solvent to obtain a partially reduced graphene oxide-magnetic oxide composite;

[0037] adding the partially reduced graphene oxide-magnetic oxide composite to an electroplating base solution containing metal ions, using the workpiece to be plated as a cathode or connected to a cathode, and forming a magnetic field around the workpiece to be plated, thereby obtaining a partially reduced graphene oxide-metal composite layer through electroplating;

[0038] After cleaning, drying and hot-pressing sintering, the graphene-metal composite layer is obtained.

[0039] The preparation method comprises: using the better-dispersed partially-reduced graphene oxide to replace graphene, and using an auxiliary agent to establish an oxygen bridge between the partially-reduced graphene oxide and the magnetic oxide and to form a partially-reduced graphene oxide-magnetic oxide composite, so that the partially-reduced graphene oxide-magnetic oxide composite has excellent dispersibility in water and is magnetic due to the compounding with the magnetic oxide; by controlling the pH value of the electroplating solution, the surface of the partially-reduced graphene oxide-magnetic oxide composite is negatively charged, and the functional groups such as carboxyl and hydroxyl in the partially-reduced graphene oxide structure are changed into -COO – and -O – , so that the surface is negatively charged and can adsorb metal ions, and the metal ions are distributed between the graphene oxide layers, further dispersing the graphene oxide; the partially-reduced graphene oxide-magnetic oxide composite is not only uniformly dispersed in the solution but also adsorbs metal ions, and after electroplating, under the joint action of the electric field and the magnetic field, the partially-reduced graphene oxide-magnetic oxide composite and the metal ions move towards the cathode together, the metal ions are reduced to form metal elements and are deposited on the surface of the plated part to form a metal plating layer, and the partially-reduced graphene oxide-magnetic oxide is embedded in the metal plating layer; after electroplating is completed, the partially-reduced graphene oxide is reduced and the magnetic oxide is reduced by hot-pressing sintering, and then an electric contact conductor material containing a graphene-metal composite layer is obtained, which not only improves the electrical conductivity but also improves the wear resistance, corrosion resistance and resistance to fusion welding; the preparation method can be applied not only to electroplating of silver, nickel, copper and the like but also to composite electroplating of copper-nickel, copper-silver, copper-tin and the like, and can greatly reduce or even eliminate the use of dispersants, thereby reducing the poisoning of the electroplating solution caused by the addition of dispersants and solving the problem of finding different dispersants to match different metal ion plating solutions in electroplating.

[0040] The preparation method uses partially-reduced graphene oxide, which comprises preparing graphene oxide and then partially reducing the graphene oxide to prepare partially-reduced graphene oxide; the preparation method of the graphene oxide can be prepared by a conventional method in the art, for example, by a process of graphite in boric acid, concentrated sulfuric acid and potassium permanganate, which is a conventional method in the art and will not be described in detail.

[0041] As a preferred technical solution of the present application, the auxiliary agent is sodium citrate.

[0042] As a preferred technical solution of the present application, graphene oxide is prepared and is prepared into a mixed system with a solvent, sodium citrate is added for partial reduction, and the magnetic oxide is added into the mixed system containing the partially-reduced graphene oxide and the sodium citrate for mixing reaction to obtain the partially-reduced graphene oxide-magnetic oxide composite.

[0043] As a preferred technical solution of the present application, the initial mass ratio of the graphene oxide, sodium citrate and magnetic oxide is 1:(8-10):(0.4-0.6), for example, 1:8:0.4, 1:8:0.5, 1:8:0.6, 1:9:0.4, 1:9:0.5, 1:9:0.6, 1:10:0.4, 1:10:0.5 or 1:10:0.6, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0044] It is worth noting that the initial mass ratio of the present application refers to the mass ratio of each material added to the system before reaction.

[0045] As a preferred technical solution of the present application, the concentration of graphene oxide in the mixed system before adding sodium citrate is 0.25-0.35g / L, for example, 0.25g / L, 0.26g / L, 0.27g / L, 0.28g / L, 0.29g / L, 0.3g / L, 0.31g / L, 0.32g / L, 0.33g / L, 0.34g / L or 0.35g / L, etc., and the temperature of the mixed system is 80-100℃, for example, 80℃, 83℃, 85℃, 88℃, 90℃, 92℃, 95℃, 97℃ or 100℃, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0046] As a preferred technical solution of the present application, the partial reduction time is 5-6h, for example, 5h, 5.1h, 5.3h, 5.5h, 5.7h, 5.9h or 6h, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0047] As a preferred technical solution of the present application, the solvent includes water.

[0048] As a preferred technical solution of the present application, the magnetic oxide includes any one or a combination of any two or three of nickel oxide, triiron tetroxide or cobalt oxide.

[0049] The prepared graphene oxide is added to water to prepare a mixed system of 0.3g / L, heated and kept at 90℃, sodium citrate is added, the mass ratio of graphene oxide to sodium citrate is 1:(8-10), and the reaction is carried out for 5-6h to obtain partially reduced graphene oxide. By controlling the reduction time, partially reduced graphene oxide can be obtained, which not only retains the dispersibility of graphene oxide, but also contains partially reduced graphene. Subsequent hot pressing sintering is easier to remove oxygen-containing functional groups in graphene oxide, and under the same migration speed in the electroplating solution, the content of magnetic oxide carried by the oxygen-containing functional groups is the lowest, such as nickel oxide.

[0050] The preparation method of the present application comprises adding nickel oxide powder into a system containing partially reduced graphene oxide and sodium citrate, ultrasonic and stirring to obtain a partially reduced graphene oxide-nickel oxide composite. Sodium citrate as an auxiliary agent can establish an oxygen bridge between the oxygen-containing groups of partially reduced graphene oxide and nickel oxide, and the partially reduced graphene oxide-nickel oxide composite is formed through the bridging effect of the oxygen bridge. Alternatively, the magnetic oxide can also be selected as ferroferric oxide. Ferroferric oxide can also establish an oxygen bridge between sodium citrate and partially reduced graphene oxide, and then form a partially reduced graphene oxide-ferroferric oxide composite. Similarly, when the magnetic oxide is selected as cobalt oxide, a partially reduced graphene oxide-cobalt oxide composite can be formed.

[0051] As a preferred technical solution of the present application, the mass concentration of the partially reduced graphene oxide-magnetic oxide composite in the electroplating solution is controlled to be 1.5-3 g / L, for example, 1.5 g / L, 1.7 g / L, 1.9 g / L, 2 g / L, 2.2 g / L, 2.4 g / L, 2.5 g / L, 2.7 g / L, 2.9 g / L or 3 g / L, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0052] As a preferred technical solution of the present application, the electroplating base solution containing metal ions includes any one of copper electroplating base solution, copper-tin electroplating base solution, silver electroplating base solution or nickel electroplating base solution.

[0053] Taking the copper electroplating base solution as an example, the partially reduced graphene oxide-nickel oxide composite is added into the copper electroplating base solution, stirred and ultrasonically dispersed. After detection, the pH value is ≥7, and the corresponding electroplating solution is obtained. The mass concentration of the partially reduced graphene oxide-nickel oxide composite in the electroplating solution is 1.5-3 g / L, the cyanide copper is 50-70 g / L, the potassium cyanide is 100-120 g / L, the potassium hydroxide is 10-20 g / L, and the potassium thiocyanate is 10-20 g / L. The specific electroplating solution preparation method is as follows: (1) prepare deionized water at room temperature; (2) add 10-20 g / L of potassium hydroxide and stir to dissolve completely; (3) add 100-130 g / L of potassium cyanide and stir to dissolve completely; (4) dilute 50-70 g / L of cyanide copper into a paste with water, then slowly add the electroplating solution obtained in step (3) while stirring until the addition is completed, so that it is fully complexed with potassium cyanide and weakly electrolyzed for one hour; (5) add 10-20 g / L of potassium thiocyanate and stir to dissolve completely; (6) add 15-30 g / L of potassium sodium tartrate and stir to dissolve completely; (7) add 1.5-3 g / L of graphene oxide-nickel oxide composite, supplement distilled water and stir, then ultrasonic for 2-6 hours, and the frequency of ultrasonic is 10-50 kHz.

[0054] The copper-tin electroplating solution obtained by using the copper-tin electroplating base solution comprises cuprous cyanide 22-25 g / L, stannous chloride 0.5-1.5 g / L, sodium cyanide 5-10 g / L, sodium hydroxide 5-10 g / L, gelatin 0.8-1.5 g / L, and partially reduced graphene oxide-nickel oxide composite 1.5-3 g / L, and is different from the copper electroplating base solution, and the metal ions in the plating solution are different, and the plating solution temperature is 40-45 DEG C.

[0055] The silver electroplating solution obtained by using the silver electroplating base solution comprises silver ions 5-10 g / L, potassium cyanide 120-210 g / L, and partially reduced graphene oxide-nickel oxide composite 1.5-3 g / L, and is different from the copper electroplating base solution, and the metal ions in the plating solution are different, and the plating solution temperature is 30-40 DEG C.

[0056] The nickel electroplating solution obtained by using the nickel electroplating base solution comprises nickel chloride 12-20 g / L, nickel sulfamate 340-380 g / L, boric acid 20-45 g / L, phosphomolybdic acid 10-30 g / L, and partially reduced graphene oxide-nickel oxide composite 1.5-3 g / L, and is different from the copper electroplating base solution, and the metal ions in the plating solution are different, and the plating solution temperature is 35-45 DEG C, and the pH value is greater than or equal to 6.5, if the pH value is less than 6.5, the partially reduced graphene oxide-nickel oxide composite is converted into positive charge, cannot adsorb metal ions, and will have an adverse effect on the intercalation and distribution of metal ions between graphene layers.

[0057] For the copper electroplating base solution, the copper-tin electroplating base solution and the silver electroplating base solution, the pH value of the final electroplating solution needs to be controlled to be greater than or equal to 7, that is, when the pH value is neutral or alkaline, the surface of the partially reduced graphene oxide-magnetic oxide composite is negatively charged, so that the metal ions can be adsorbed.

[0058] As a preferred technical scheme of the present application, a coil is wound on the cathode to form a magnetic field around the workpiece in an electro-magnetic manner.

[0059] As a preferred technical scheme of the present application, the number of winding turns of the coil is 15-1000 turns, for example, 15 turns, 45 turns, 80 turns, 100 turns, 130 turns, 150 turns, 200 turns, 350 turns, 400 turns, 550 turns, 650 turns, 700 turns, 800 turns, 900 turns or 1000 turns, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0060] It is worth mentioning that the workpiece to be plated is used as the cathode or connected with the cathode, the coil is wound on the cathode, the power supply wire of the electroplating cathode can be wound on the coil, or a new power supply wire is additionally prepared on the basis of the power supply wire of the electroplating cathode and wound on the coil, the position of the workpiece to be plated can be set as the positive pole or the negative pole of the magnetic field, as long as the magnetic field around the workpiece to be plated is formed in an electro-magnetic manner, so that the workpiece to be plated itself generates magnetism under the action of the magnetic field and generates attraction to metal ions. The number of turns of the coil is greater than 15, the more turns of the coil, the faster the deposition speed, but it will cause a lot of graphene oxide deposition, hinder the reduction of metal ions, and the compactness of the electroplating layer is poor, and the preferred number of turns of the coil is less than 1000.

[0061] As an example, the schematic diagram of winding the coil in the preparation method of the graphene-metal composite layer of the present application is shown in Figure 1 As shown in the figure, the electroplating tank 1 is filled with the prepared electroplating solution, the anode 3 and the cathode 4 are immersed in the electroplating solution, and the power supply device 2 is used to supply power to the anode 3 and the cathode 4 respectively, and the workpiece 7 to be plated is hung on the lower end of the cathode 4 through the hanger 6; wherein the coil 5 is wound on the cathode 4, and after the coil 5 is powered on, a magnetic field can be formed around the workpiece 7 to be plated in an electro-magnetic manner, so that the workpiece 7 to be plated itself generates magnetism under the action of the magnetic field and generates attraction to metal ions.

[0062] As a preferred technical solution of the present application, the drying is vacuum drying, the temperature of the vacuum drying is 100-150℃, for example, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, etc., and the time of the vacuum drying is 20-35min, for example, 20min, 23min, 25min, 28min, 30min, 31min, 33min or 35min, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0063] The preparation method of the present application uses vacuum drying, which can remove most of the water on the surface of the electroplated product under vacuum conditions after electroplating, although it cannot remove the oxygen atoms inside the material, at this time the graphene is partially oxidized graphene, which has defects and poor thermal and electrical conductivity. The graphene-metal composite layer can be obtained by subsequent hot pressing sintering of the electroplated product.

[0064] As a preferred technical solution of the present application, the temperature of the hot-pressing sintering is 800-1000℃, for example, 800℃, 820℃, 850℃, 860℃, 880℃, 900℃, 930℃, 950℃, 970℃ or 1000℃, etc., and the holding time of the hot-pressing sintering is 35-40min, for example, 35min, 36min, 37min, 38min, 39min or 40min, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0065] As a preferred technical solution of the present application, the temperature of the hot-pressing sintering is below 450℃, and the heating rate is controlled at 7-9℃ / min, for example, 7℃ / min, 7.2℃ / min, 7.4℃ / min, 7.5℃ / min, 7.7℃ / min, 7.9℃ / min, 8℃ / min, 8.2℃ / min, 8.5℃ / min, 8.8℃ / min or 9℃ / min, etc.; and the temperature of the hot-pressing sintering is above 450℃, and the heating rate is controlled at 14-16℃ / min, for example, 14℃ / min, 14.2℃ / min, 14.4℃ / min, 14.6℃ / min, 14.8℃ / min, 15℃ / min, 15.3℃ / min, 15.5℃ / min, 15.7℃ / min or 16℃ / min, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0066] As a preferred technical solution of the present application, the hot-pressing sintering is pressurized by hydrogen and / or methane, and the pressure of the hot-pressing sintering is controlled at 25-35MPa, for example, 25MPa, 26MPa, 28MPa, 30MPa, 31MPa, 33MPa or 35MPa, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0067] In the hot-pressing sintering, hydrogen and / or methane is used for pressurization, which not only extrudes water and carbon dioxide produced by the decomposition of graphene oxide in the electroplated conductor material from the inside of the metal conductor, but also enters the reducing gas (hydrogen and / or methane) into the channel formed by the extrusion to reduce nickel oxide, and the high-temperature sintering also reduces the internal gap of the composite material, making the graphene layers more compact, and the reduced nickel forms an alloy with copper, thereby increasing the overall performance of the conductor material.

[0068] In summary, the present application provides a preparation method of graphene-metal composite layer, which first prepares graphene oxide and partially reduces it, mixes the obtained partially reduced graphene oxide, an auxiliary agent and a magnetic oxide in a solvent to prepare a partially reduced graphene oxide-magnetic oxide composite, and then adds it into an electroplating base solution containing metal ions, so that the graphene oxide-magnetic oxide composite can be uniformly distributed in the electroplating solution and can adsorb metal ions; after electroplating, under the joint action of electric field and magnetic field, the metal ions are reduced to metal elements and deposited on the surface of the plated part to form a metal plating layer, and the graphene oxide-magnetic oxide composite is embedded in the metal plating layer, so that the graphene oxide can be reduced and the magnetic oxide can be reduced in subsequent hot-pressing sintering to obtain an electric contact conductor material containing a graphene-metal composite layer, which not only improves the electrical conductivity, but also improves the wear resistance, corrosion resistance and anti-welding property.

[0069] The present application is described by the above-mentioned embodiments to illustrate the detailed process equipment and process flow of the present application, but the present application is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present application must rely on the above-mentioned detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing a graphene-metal composite layer, characterized in that: The preparation method comprises the following steps: Graphene oxide is prepared and mixed with a solvent to obtain a mixed system, sodium citrate is added for partial reduction, and a magnetic oxide is added to the mixed system containing the partially reduced graphene oxide and the sodium citrate for a mixed reaction to obtain a partially reduced graphene oxide-magnetic oxide composite; adding the partially reduced graphene oxide-magnetic oxide composite to an electroplating base solution containing metal ions, using the workpiece to be plated as a cathode or connected to a cathode, and forming a magnetic field around the workpiece to be plated, thereby obtaining a partially reduced graphene oxide-metal composite layer through electroplating; After cleaning, drying and hot pressing and sintering, a graphene-metal composite layer is obtained.

2. The preparation method according to claim 1, characterized in that The initial mass ratio of the graphene oxide, sodium citrate and magnetic oxide is controlled to be 1:(8-10):(0.4-0.6).

3. The preparation method according to claim 2, characterized in that Before adding sodium citrate, the concentration of graphene oxide in the mixed system is 0.25-0.35 g / L, and the temperature of the mixed system is 80-100° C.

4. The preparation method according to claim 1, characterized in that The time for the partial reduction is 5-6 hours.

5. The preparation method according to claim 1, characterized in that The magnetic oxide includes any one of nickel oxide, ferrosoferric oxide or cobalt oxide, or a combination of any two or three thereof.

6. The preparation method according to claim 1, characterized in that The partially reduced graphene oxide-magnetic oxide composite is added to an electroplating base solution containing metal ions, and the mass concentration of the partially reduced graphene oxide-magnetic oxide composite in the obtained electroplating solution is controlled to be 1.5-3 g / L.

7. The preparation method according to claim 1, characterized in that The electroplating base liquid containing metal ions includes any one of a copper electroplating base liquid, a copper-tin electroplating base liquid, a silver electroplating base liquid or a nickel electroplating base liquid.

8. The preparation method according to claim 1, characterized in that A coil is wound around the cathode to form a magnetic field around the workpiece to be plated in an electromagnetic manner.

9. The preparation method according to claim 8, characterized in that The number of winding turns of the coil is 15-1000 turns.

10. The preparation method according to claim 1, characterized in that The drying is vacuum drying, the vacuum drying temperature is 100-150° C., and the vacuum drying time is 20-35 min.

11. The preparation method according to claim 1, characterized in that The temperature of the hot pressing sintering is 800-1000° C., and the holding time of the hot pressing sintering is 35-40 minutes.

12. The preparation method according to claim 11, characterized in that The temperature of the hot pressing sintering is below 450° C., and the heating rate is controlled to be 7-9° C. / min; the temperature of the hot pressing sintering is above 450° C., and the heating rate is controlled to be 14-16° C. / min.

13. The preparation method according to claim 1, characterized in that The hot pressing sintering is performed by applying pressure using hydrogen and / or methane, and the pressure of the hot pressing sintering is controlled to be 25-35 MPa.

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