Method for preparing a foamed metal composite having good electrical conductivity and wear resistance

Abstract

This invention discloses a foamed metal composite material with good electrical conductivity and wear resistance, and its preparation method, comprising the following steps: Step (1) Pre-treating the surface of the foamed metal; Step (2) Heat-treating expanded graphite and graphene oxide respectively; Step (3) Dispersing cellulose in water to obtain a cellulose dispersion; adding carbon fiber, heat-treated expanded graphite, and heat-treated graphene oxide to the cellulose dispersion, stirring and mixing evenly to obtain a paste-like mixed filler; Step (4) Pressing the paste-like mixed filler into the pores of the foamed metal at room temperature and vacuum drying to obtain a preform; Step (5) Treating the preform with carbon pyrolysis using isothermal chemical vapor infiltration, and after the carbon pyrolysis treatment is completed, a foamed metal composite material with good electrical conductivity and wear resistance is obtained. This invention can solve the technical problem of unsatisfactory electrical conductivity and wear resistance of existing carbon / metal-based conductive composite materials.

Description

Technical Field

[0001] This invention relates to the field of carbon / metal-based conductive composite materials. Specifically, it relates to a method for preparing foamed metal composite materials with good conductivity and wear resistance. Background Technology

[0002] Carbon materials have a long history and are diverse in type. They can be broadly classified into three categories: traditional carbon materials, specialty carbon materials, and nanomaterials. Traditional carbon materials include charcoal, activated carbon, and natural graphite; specialty carbon materials include diamond, carbon fiber, and flexible graphite; and nanomaterials include fullerenes, carbon nanotubes, and graphene. Advanced carbon-based composite materials are a type of carbon material, and their development can be divided into three stages: from the mid-1960s, a stage of technological exploration, to the 1990s, when they began to be applied in the aerospace field; and from the 1990s to the present, they have entered the stage of development and application in the civilian sector.

[0003] Carbon / carbon composites are all-carbon composite materials made from graphite carbon as the matrix phase and carbon fiber as the reinforcing phase through specific processing techniques. They are among the most widely used advanced carbon-based materials and are considered one of the most promising materials of the 21st century due to their unique and excellent properties. Carbon / carbon composites are characterized by high density and light weight (1.7-2.0 g / cm³). 3 Carbon / carbon composites possess excellent wear resistance and impact resistance, and their theoretical high-temperature resistance can reach 2600℃, making them one of the most promising high-temperature resistant materials. Furthermore, carbon / metal matrix composites, formed by combining carbon / carbon composites with metal materials, not only possess the various excellent properties of carbon materials and the strength of metal materials, but also exhibit higher mechanical properties and elastic modulus.

[0004] Metal composite materials are generally made of aluminum, magnesium, copper, nickel, titanium, and their alloys. Materials combining metals with carbon / carbon composites exhibit better overall performance compared to carbon / carbon composites or pure metal materials. Copper, in particular, possesses advantages such as high electrical and thermal conductivity and low cost compared to other metals. Nickel, due to its high-temperature resistance, oxidation resistance, and corrosion resistance, is also widely used alongside copper in fields such as slider conductors, graphite metal brushes, and aerospace. Currently, research on preparing highly conductive carbon / metal-based conductive composite materials by combining metals with carbon materials is still in its infancy, and the practical application results of the prepared materials are not ideal. Therefore, developing and designing methods for preparing foam metal composite materials with good conductivity and wear resistance remains essential. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide a method for preparing a foam metal composite material with good conductivity and wear resistance, so as to solve the technical problem that the conductivity and wear resistance of existing carbon / metal-based conductive composite materials are not ideal.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A method for preparing foamed metal composite materials with good electrical conductivity and wear resistance includes the following steps:

[0008] Step (1): Pre-treat the surface of the foamed metal;

[0009] Step (2): Heat-treat expanded graphite and graphene oxide respectively;

[0010] Step (3): Disperse cellulose in water to obtain cellulose dispersion; add carbon fiber, heat-treated expanded graphite and heat-treated graphene oxide to the cellulose dispersion, stir and mix evenly to obtain paste-like mixed filler.

[0011] Step (4): Press the paste-like mixed filler into the pores of the foam metal at room temperature and vacuum dry to obtain a preform;

[0012] Step (5): The preform is subjected to carbon pyrolysis treatment using isothermal chemical vapor infiltration. Once the carbon pyrolysis treatment is completed, a foam metal composite material with good electrical conductivity and wear resistance is obtained.

[0013] Because pure carbon fiber has poor formability, it is easy to detach from the pores of foamed copper during the cold pressing process for preform preparation. At the same time, pure carbon fiber has low electrical and thermal conductivity after carburizing. In contrast, expanded graphite and graphene oxide have high electrical and thermal conductivity. During the pyrolysis and carburizing process, they can recombine with the active carbon atoms in the pyrolytic carbon, effectively improving the electrical and thermal conductivity of the composite material. In addition, the addition of both can effectively improve the bonding force and mechanical properties with carbon fiber.

[0014] The above-mentioned method for preparing foam metal composite materials with good electrical conductivity and wear resistance, wherein the foam metal in step (1) is foam copper or foam nickel; the porosity of the foam metal is 10-20 PP I, which can ensure that the paste-like mixed filler can smoothly enter the foam metal skeleton, effectively improve the density of the preform, and avoid the phenomenon of the paste-like mixed filler filling the foam metal skeleton leaking from the pores after drying.

[0015] The method for pretreatment of the surface of foamed copper is as follows: place the foamed copper in a dilute hydrochloric acid solution with a concentration of 1-2 mol / L and sonicate for 10-20 minutes. After sonication, take out the foamed copper and transfer it to an acetone solution with a mass fraction of 99 wt% (the mass ratio of acetone to water is 99:1) and sonicate for 10-20 minutes. After cleaning, take it out and let it air dry.

[0016] The pretreatment method for the surface of nickel foam is as follows: Place the copper foam in a dilute hydrochloric acid solution with a concentration of 1–2 mol / L and sonicate for 10–20 min. After sonication, remove the copper foam and transfer it to a 99 wt% acetone solution for ultrasonic cleaning for 10–20 min. After cleaning, remove and air dry. Then, plate copper onto the surface of the nickel foam using electroplating. During electroplating, prepare a 700 mL electroplating solution by adding 50 g of 98 wt% concentrated sulfuric acid and 100 g of copper sulfate to deionized water. The electroplating current is 0.3 A, and the electroplating time is 3–4 h. After electroplating, transfer the copper-plated nickel foam to anhydrous ethanol for ultrasonic cleaning for 5 min. After ultrasonic cleaning, remove and place in a vacuum drying oven for drying for 2–8 h at a drying temperature of 60℃.

[0017] In the preparation method of the above-mentioned foam metal composite material with good conductivity and wear resistance, in step (2), both expanded graphite and graphene oxide are subjected to the following heat treatment: the expanded graphite or graphene oxide is heated to 900-950℃ at a heating rate of 5-10℃ / min under a normal pressure nitrogen protective atmosphere, and the heat treatment is held for 1-2 hours; after the holding time is completed, it is cooled to room temperature. This heat treatment method can remove oxygen-containing functional groups between the layers of expanded graphite and on the surface of graphene oxide to improve its physical properties; at a temperature of 900-950℃, the oxygen-containing functional groups between the layers of expanded graphite or graphene oxide can be effectively removed. If the heat treatment temperature is too low, sufficient expansion and removal of oxygen-containing functional groups cannot be achieved, resulting in low yield and poor quality; if the temperature is too high, it is not energy-saving and environmentally friendly; a holding time of 1-2 hours can make the expanded graphite and graphene oxide have ideal uniformity after heat treatment.

[0018] In the preparation method of the above-mentioned foam metal composite material with good electrical conductivity and wear resistance, in step (2), the heat treatment conditions of expanded graphite are as follows: the expanded graphite is heated to 900℃ at a heating rate of 5℃ / min under a normal pressure nitrogen protective atmosphere and held for 2h; after the holding period, it is cooled to room temperature; the heat treatment conditions of graphene oxide are as follows: the graphene oxide is heated to 950℃ at a heating rate of 10℃ / min under a normal pressure nitrogen protective atmosphere and held for 1h; after the holding period, it is cooled to room temperature.

[0019] In the preparation method of the above-mentioned foam metal composite material with good conductivity and wear resistance, in step (3), the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-10 μm; the cellulose is methylcellulose, sodium carboxymethylcellulose or hydroxyethylcellulose, and the mass concentration of cellulose in the cellulose dispersion is 0.1-0.2 g / mL. Among them, the carbon fiber with a length of 1-2 mm and a diameter of 6-10 μm used in this invention has the best dispersion effect in hydroxyethylcellulose; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:(1-3):1, and the mass ratio of carbon fiber to cellulose is (1-3):1.

[0020] In the preparation method of the above-mentioned foam metal composite material with good conductivity and wear resistance, in step (3), the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-7 μm; the cellulose is hydroxyethyl cellulose, and the mass concentration of cellulose in the cellulose dispersion is 0.2 g / mL. This concentration of cellulose dispersion can make the obtained paste-like mixed filler have a moderate consistency, which is conducive to pressing into the foam metal skeleton, and can effectively avoid the paste-like mixed filler flowing out of the skeleton and making it difficult to form; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:2:1, and the mass ratio of carbon fiber to cellulose is 2:1; too much or too little expanded graphene or graphene oxide will affect the formability of the paste-like mixed filler after filling.

[0021] In the preparation method of the above-mentioned foam metal composite material with good conductivity and wear resistance, in step (4), the pressure when pressing the paste-like mixed filler into the pores of the foam metal is 50-100 MPa. If the filling pressure is lower than 50 MPa, the paste-like mixed filler will have poor filling performance inside the foam metal. However, if the pressure is greater than 100 MPa, the paste-like mixed filler will easily be extruded, affecting the filling effect. The drying temperature during vacuum drying is 70-100℃, and the drying time is 2-8 hours, forming a short carbon fiber / expanded graphite / graphene oxide preform with foam copper as the skeleton. Under the drying conditions of the present invention, the drying effect is good, and the paste-like mixed filler will not cause the preform to be damaged during the drying process. The block expands from the inside and collapses; in step (5), when the preform is treated with carbon by isothermal chemical vapor infiltration: the volume ratio of methane to nitrogen is 1:1.5, and the gas flow rate of methane and nitrogen should not be too large or too small. Too large or too small a flow rate will lead to low gas cracking efficiency and gas waste. When the volume ratio of methane to nitrogen is 1:1.5, the methane cracking efficiency is the highest and the carbon treatment effect is the best; the gas cracking temperature is 1020~1080℃, the atmosphere pressure is 20~40Kpa, and the densification time is 200~300h; under the above cracking treatment conditions of the present invention, the methane cracking efficiency is high, the carbon treatment efficiency is high, and the activated carbon in the pyrolysis carbon and the expanded graphite in the preform have a good recombination effect, which can significantly improve the electrical and thermal conductivity of the composite material.

[0022] In the preparation method of the above-mentioned foam metal composite material with good conductivity and wear resistance, in step (4), the pressure when the paste-like mixed filler is pressed into the pores of the foam metal is 100 MPa; the drying temperature during vacuum drying is 100℃ and the drying time is 8h; in step (5), when the preform is treated with carbon pyrolysis by isothermal chemical vapor infiltration: the volume ratio of methane to nitrogen is 1:1.5, the gas pyrolysis temperature is 1050℃, the atmosphere pressure is 35Kpa, and the densification time is 280h.

[0023] The above-mentioned method for preparing foam metal composite material with good electrical conductivity and wear resistance also includes step (6): further electroplating copper on the surface of the product after the carbon pyrolysis treatment, and obtaining foam metal composite material with good electrical conductivity and wear resistance after the copper electroplating treatment.

[0024] In the preparation method of the above-mentioned foam metal composite material with good conductivity and wear resistance, during the copper electroplating treatment in step (6): 50g of concentrated sulfuric acid with a mass fraction of 98wt% and 100g of copper sulfate are added to deionized water to prepare 700mL of electroplating solution. The electroplating current is 0.3A and the electroplating time is 3-4h. After the electroplating is completed, the copper-plated nickel foam is transferred to anhydrous ethanol for ultrasonic cleaning for 5min. After ultrasonic cleaning, it is taken out and placed in a vacuum drying oven for drying for 2-8h at a drying temperature of 60℃.

[0025] The technical solution of the present invention achieves the following beneficial technical effects:

[0026] 1. This invention discloses a method for preparing a foamed metal composite material with good electrical conductivity and wear resistance. Expanded graphite and graphene oxide are mixed with carbon fibers of specific length and thickness as filler materials for the foamed metal. This enhances the bonding strength between the foamed metal and the carbon fiber materials and effectively reduces the electrical and thermal resistance of the prepared composite material, resulting in a foamed metal composite material with good electrical conductivity and wear resistance. The foamed metal composite material with good electrical conductivity and wear resistance prepared using this method can be applied in fields such as friction materials, pantograph sliding plate materials, brush materials, electrical contact materials, and mechanical parts materials.

[0027] 2. This invention fills a foamed metal skeleton with a specific ratio of expanded graphite and graphene oxide, which can recombine with active carbon atoms in pyrolytic carbon during isothermal chemical vapor infiltration, fusing carbon fibers with expanded graphite and graphene oxide into a whole. This not only significantly reduces interfacial thermal resistance and electrical resistance but also improves the overall bonding strength and wear resistance of the composite material. Furthermore, the three-dimensional interconnected metal skeleton effectively ensures the continuity of the composite material in three dimensions, further improving its strength and mechanical properties, effectively inhibiting crack propagation, and providing excellent electrical and thermal conductivity. This results in significantly improved electrical and thermal conductivity in all directions of the prepared foamed metal composite material. Therefore, the foamed metal-carbon fiber / expanded graphite / graphene oxide composite material prepared using the method of this invention possesses excellent mechanical properties, electrical conductivity, and wear resistance. Attached Figure Description

[0028] Figure 1 A photograph of the nickel foam raw material used in Example 2 of this invention;

[0029] Figure 2 A photograph of the actual product of the nickel foam used in Example 2 of this invention after being electroplated with copper;

[0030] Figure 3 A physical image of the preformed block prepared in step (4) of Embodiment 2 of the present invention;

[0031] Figure 4 A physical image of the foamed metal composite material with good electrical conductivity and wear resistance obtained after carbon pyrolysis treatment in Example 2 of this invention. Detailed Implementation

[0032] Example 1

[0033] The preparation method of the foamed metal composite material with good electrical conductivity and wear resistance in this embodiment includes the following steps:

[0034] Step (1): Surface pretreatment of copper foam; the porosity of copper foam is 20 PP I; the surface pretreatment method is as follows: place copper foam in a dilute hydrochloric acid solution with a concentration of 2 mol / L and sonicate for 10 min. After sonication, take out copper foam and transfer it to an acetone solution with a mass fraction of 99 wt% and sonicate for 10 min. After cleaning, take out and air dry.

[0035] Step (2): Heat treatment of expanded graphite and graphene oxide respectively; Heat treatment conditions for expanded graphite: Heat expanded graphite to 900℃ at a heating rate of 5℃ / min under normal pressure nitrogen atmosphere, hold for 2h; After holding, cool to room temperature; Heat treatment conditions for graphene oxide: Heat graphene oxide to 950℃ at a heating rate of 10℃ / min under normal pressure nitrogen atmosphere, hold for 1h; After holding, cool to room temperature.

[0036] Step (3): Disperse cellulose in water to obtain a cellulose dispersion; add carbon fiber, heat-treated expanded graphite and heat-treated graphene oxide to the cellulose dispersion, stir and mix evenly to obtain a paste-like mixed filler; the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-7 μm; the cellulose is hydroxyethyl cellulose and the mass concentration of cellulose in the cellulose dispersion is 0.1 g / mL; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:1:1, and the mass ratio of carbon fiber to cellulose is 1:1.

[0037] Step (4): The paste-like mixed filler is pressed into the pores of the pretreated copper foam at room temperature using a pressure of 100 MPa, and then vacuum dried at 100°C for 8 hours to obtain the preform.

[0038] Step (5): The preform is subjected to carbon pyrolysis treatment using isothermal chemical vapor infiltration. When the preform is subjected to carbon pyrolysis treatment using isothermal chemical vapor infiltration, the volume ratio of methane to nitrogen is 1:1.5, the gas pyrolysis temperature is 1050℃, the atmosphere pressure is 35Kpa, and the densification time is 280h. After the carbon pyrolysis treatment is completed, a foam metal composite material with good electrical conductivity and wear resistance is obtained.

[0039] The resistivity of the foamed metal composite material prepared in this embodiment is 0.716 × 10⁻⁶. -7 Ω·m (≤1.4×10) -7 Ω·m), thermal conductivity is 120 W / (m·K) -1 )(≥100W(m·k -1 Its wear resistance is about 1.5 times that of ordinary carbon-carbon composite materials, and its coefficient of friction is 0.155.

[0040] Example 2

[0041] The preparation method of the foamed metal composite material with good electrical conductivity and wear resistance in this embodiment includes the following steps:

[0042] Step (1): Surface pretreatment of nickel foam; the porosity of nickel foam is 15 PPI; the surface pretreatment method is as follows: place nickel foam in a dilute hydrochloric acid solution with a concentration of 2 mol / L and sonicate for 10 min. After sonication, take out the nickel foam and transfer it to an acetone solution with a mass fraction of 99 wt% and sonicate for 10 min. After cleaning, take it out and let it dry; then use electroplating to plate copper on the surface of nickel foam. During electroplating, 700 mL of electroplating solution is prepared by adding 50 g of concentrated sulfuric acid with a mass fraction of 98 wt% and 100 g of copper sulfate to deionized water. The electroplating current is 0.3 A and the electroplating time is 4 h; after electroplating, transfer the copper-plated nickel foam to anhydrous ethanol and sonicate for 5 min. After sonication, take it out and place it in a vacuum drying oven to dry for 8 h at a drying temperature of 60 ℃.

[0043] Step (2): Heat treatment of expanded graphite and graphene oxide respectively; Heat treatment conditions for expanded graphite: Heat expanded graphite to 900℃ at a heating rate of 5℃ / min under normal pressure nitrogen atmosphere, hold for 2h; After holding, cool to room temperature; Heat treatment conditions for graphene oxide: Heat graphene oxide to 950℃ at a heating rate of 10℃ / min under normal pressure nitrogen atmosphere, hold for 1h; After holding, cool to room temperature.

[0044] Step (3): Disperse cellulose in water to obtain a cellulose dispersion; add carbon fiber, heat-treated expanded graphite and heat-treated graphene oxide to the cellulose dispersion, stir and mix evenly to obtain a paste-like mixed filler; the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-7 μm; the cellulose is hydroxyethyl cellulose and the mass concentration of cellulose in the cellulose dispersion is 0.2 g / mL; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:2:1, and the mass ratio of carbon fiber to cellulose is 2:1.

[0045] Step (4): The paste-like mixed filler is pressed into the pores of the pretreated nickel foam at room temperature using a pressure of 100 MPa, and then vacuum dried at 100°C for 8 hours to obtain a preform.

[0046] Step (5): The preform is subjected to carbon pyrolysis treatment using isothermal chemical vapor infiltration. When the preform is subjected to carbon pyrolysis treatment using isothermal chemical vapor infiltration, the volume ratio of methane to nitrogen is 1:1.5, the gas pyrolysis temperature is 1050℃, the atmosphere pressure is 35Kpa, and the densification time is 280h. After the carbon pyrolysis treatment is completed, a foam metal composite material with good electrical conductivity and wear resistance is obtained.

[0047] The resistivity of the foamed metal composite material prepared in this embodiment is 0.382 × 10⁻⁶. -7 (≤6×10 -7 Ω·m), thermal conductivity is 135 W / (m·K) -1 Its coefficient of friction is 0.135.

[0048] Example 3

[0049] The preparation method of the foamed metal composite material with good electrical conductivity and wear resistance in this embodiment includes the following steps:

[0050] Step (1): Surface pretreatment of nickel foam; the porosity of nickel foam is 10 PPI; the surface pretreatment method is as follows: place nickel foam in a dilute hydrochloric acid solution with a concentration of 2 mol / L and sonicate for 10 min. After sonication, take out the nickel foam and transfer it to an acetone solution with a mass fraction of 99 wt% and sonicate for 10 min. After cleaning, take it out and let it dry; then use electroplating to plate copper on the surface of nickel foam. During electroplating, 700 mL of electroplating solution is prepared by adding 50 g of concentrated sulfuric acid with a mass fraction of 98 wt% and 100 g of copper sulfate to deionized water. The electroplating current is 0.3 A and the electroplating time is 4 h; after electroplating, transfer the copper-plated nickel foam to anhydrous ethanol and sonicate for 5 min. After sonication, take it out and place it in a vacuum drying oven to dry for 8 h at a drying temperature of 60 ℃.

[0051] Step (2): Heat treatment of expanded graphite and graphene oxide respectively; Heat treatment conditions for expanded graphite: Heat expanded graphite to 900℃ at a heating rate of 5℃ / min under normal pressure nitrogen atmosphere, hold for 2h; After holding, cool to room temperature; Heat treatment conditions for graphene oxide: Heat graphene oxide to 950℃ at a heating rate of 10℃ / min under normal pressure nitrogen atmosphere, hold for 1h; After holding, cool to room temperature.

[0052] Step (3): Disperse cellulose in water to obtain a cellulose dispersion; add carbon fiber, heat-treated expanded graphite and heat-treated graphene oxide to the cellulose dispersion, stir and mix evenly to obtain a paste-like mixed filler; the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-7 μm; the cellulose is hydroxyethyl cellulose and the mass concentration of cellulose in the cellulose dispersion is 0.15 g / mL; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:3:1, and the mass ratio of carbon fiber to cellulose is 3:1.

[0053] Step (4): The paste-like mixed filler is pressed into the pores of the pretreated nickel foam at room temperature using a pressure of 100 MPa, and then vacuum dried at 100°C for 8 hours to obtain the preform.

[0054] Step (5): The preform is treated with carbon pyrolysis using isothermal chemical vapor infiltration. When treating the preform with carbon pyrolysis using isothermal chemical vapor infiltration, the volume ratio of methane to nitrogen is 1:1.5, the gas pyrolysis temperature is 1050℃, the atmosphere pressure is 35Kpa, and the densification time is 280h.

[0055] Step (6): The product after the carbon pyrolysis treatment is further subjected to surface electroplating with copper. During the copper electroplating treatment, 700 mL of electroplating solution is prepared by adding 50 g of concentrated sulfuric acid with a mass fraction of 98 wt% and 100 g of copper sulfate to deionized water. The electroplating current is 0.3 A and the electroplating time is 4 h. After the electroplating is completed, the copper-plated composite material is transferred to anhydrous ethanol for ultrasonic cleaning for 5 min. After ultrasonic cleaning, it is taken out and placed in a vacuum drying oven for drying for 8 h at a drying temperature of 60 °C. After the copper electroplating treatment, a foam metal composite material with good conductivity and wear resistance is obtained.

[0056] The resistivity of the foamed metal composite material prepared in this embodiment is 1.06 × 10⁻⁶. -6 Its electrical conductivity is comparable to that of pure copper; its thermal conductivity is 125 W / (m·K). -1 Its coefficient of friction is 0.15.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for preparing a foamed metal composite material with good electrical conductivity and wear resistance, characterized in that, Includes the following steps: Step (1): Pre-treat the surface of the foamed metal; Step (2): Heat-treat expanded graphite and graphene oxide respectively; Step (3): Disperse cellulose in water to obtain cellulose dispersion; add carbon fiber, heat-treated expanded graphite and heat-treated graphene oxide to the cellulose dispersion, stir and mix evenly to obtain paste-like mixed filler. Step (4): Press the paste-like mixed filler into the pores of the foam metal at room temperature and vacuum dry to obtain a preform; Step (5): The preform is subjected to carbon pyrolysis treatment using isothermal chemical vapor infiltration. After the carbon pyrolysis treatment is completed, a foam metal composite material with good electrical conductivity and wear resistance is obtained. In step (2), both expanded graphite and graphene oxide are subjected to the following heat treatment: the expanded graphite or graphene oxide is heated to 900-950°C at a heating rate of 5-10°C / min under a normal pressure nitrogen protective atmosphere and held for 1-2 hours; after the holding period, it is cooled to room temperature. In step (3), the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-10 μm; the cellulose is methylcellulose, sodium carboxymethylcellulose or hydroxyethylcellulose, and the mass concentration of cellulose in the cellulose dispersion is 0.1-0.2 g / mL; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:(1-3):1, and the mass ratio of carbon fiber to cellulose is (1-3):

1. In step (4), the pressure when pressing the paste-like mixed filler into the pores of the foam metal is 50-100 MPa; the drying temperature during vacuum drying is 70-100℃, and the drying time is 2-8 h. In step (5), when the preform is subjected to carbon pyrolysis treatment by isothermal chemical vapor infiltration, the volume ratio of methane to nitrogen is 1:1.5, the gas pyrolysis temperature is 1020-1080℃, the atmosphere pressure is 20-40Kpa, and the densification time is 200-300h.

2. The method for preparing the foamed metal composite material with good electrical conductivity and wear resistance according to claim 1, characterized in that, In step (1), the foam metal is foam copper or foam nickel; the porosity of the foam metal is 10-20 PPI; the method for pre-treating the surface of foam copper is as follows: place the foam copper in a dilute hydrochloric acid solution with a concentration of 1-2 mol / L and sonicate for 10-20 min. After the sonication is completed, take out the foam copper and transfer it to an acetone solution with a mass fraction of 99 wt% and sonicate for 10-20 min. After cleaning, take it out and let it air dry. The pretreatment method for the surface of nickel foam is as follows: The nickel foam is placed in a 1–2 mol / L dilute hydrochloric acid solution and ultrasonically treated for 10–20 min. After ultrasonic treatment, the nickel foam is removed and transferred to a 99 wt% acetone solution for ultrasonic cleaning for 10–20 min. After cleaning, it is removed and air-dried. Then, copper is plated onto the surface of the nickel foam using electroplating. During electroplating, 700 mL of electroplating solution is prepared by adding 50 g of 98 wt% concentrated sulfuric acid and 100 g of copper sulfate to deionized water. The electroplating current is 0.3 A, and the electroplating time is 3–4 h. After electroplating, the copper-plated nickel foam is transferred to anhydrous ethanol and ultrasonically cleaned for 5 min. After ultrasonic cleaning, it is removed and placed in a vacuum drying oven for drying for 2–8 h at a drying temperature of 60℃.

3. The method for preparing the foamed metal composite material with good electrical conductivity and wear resistance according to claim 1, characterized in that, In step (2), the heat treatment conditions for expanded graphite are as follows: the expanded graphite is heated to 900℃ at a heating rate of 5℃ / min under a normal pressure nitrogen atmosphere and held for 2h; after the holding period, it is cooled to room temperature. The heat treatment conditions for graphene oxide are as follows: the graphene oxide is heated to 950℃ at a heating rate of 10℃ / min under a normal pressure nitrogen atmosphere and held for 1h; after the holding period, it is cooled to room temperature.

4. The method for preparing the foamed metal composite material with good electrical conductivity and wear resistance according to claim 1, characterized in that, In step (3), the length of the carbon fiber is 1-2 mm and the diameter of the carbon fiber is 6-7 μm; the cellulose is hydroxyethyl cellulose and the mass concentration of cellulose in the cellulose dispersion is 0.2 g / mL; in the paste-like mixed filler, the mass ratio of carbon fiber, expanded graphite and graphene oxide is 1:2:1 and the mass ratio of carbon fiber to cellulose is 2:

1.

5. The method for preparing the foamed metal composite material with good electrical conductivity and wear resistance according to claim 1, characterized in that, In step (4), the pressure when pressing the paste-like mixed filler into the pores of the foam metal is 100 MPa; the drying temperature during vacuum drying is 100℃ and the drying time is 8 hours. In step (5), when the preform is subjected to carbon pyrolysis treatment by isothermal chemical vapor infiltration, the volume ratio of methane to nitrogen is 1:1.5, the gas pyrolysis temperature is 1050℃, the atmosphere pressure is 35Kpa, and the densification time is 280h.

6. The method for preparing the foamed metal composite material with good electrical conductivity and wear resistance according to claim 1, characterized in that, It also includes step (6): further electroplating copper on the surface of the product after the carbon pyrolysis treatment, and obtaining a foam metal composite material with good conductivity and wear resistance after the copper electroplating treatment.

7. The method for preparing the foamed metal composite material with good electrical conductivity and wear resistance according to claim 6, characterized in that, In step (6), when the foam metal is nickel foam, the copper plating process is as follows: 50g of concentrated sulfuric acid with a mass fraction of 98wt% and 100g of copper sulfate are added to deionized water to prepare 700mL of electroplating solution. The electroplating current is 0.3A and the electroplating time is 3-4h. After the electroplating is completed, the copper-plated nickel foam is transferred to anhydrous ethanol for ultrasonic cleaning for 5min. After ultrasonic cleaning, it is taken out and placed in a vacuum drying oven for drying for 2-8h at a drying temperature of 60℃.

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