Graphene-reinforced copper-based electrical contact material and method for manufacturing the same

Abstract

The application provides a graphene reinforced copper-based electric contact material and a preparation method thereof, and the raw materials of the electric contact material comprise, in percentage by mass, 15-35% of tungsten powder, 1-10% of chromium powder, 1-5% of molybdenum powder, 0.1-1% of cerium oxide powder, 0.5-2% of copper-based graphene powder, and the balance of copper powder. The graphene reinforced copper-based electric contact material and the preparation method thereof effectively solve the problems of poor interface wetting between graphene and copper and easy oxidation of copper by performing copper-based surface treatment on graphene, so that the obtained electric contact material has excellent mechanical properties, electrical conductivity and oxidation resistance.

Description

Technical Field

[0001] This invention relates to the field of electronic and electrical materials technology, and in particular to a graphene-reinforced copper-based electrical contact material and its preparation method. Background Technology

[0002] Contacts, also known as contacts or junctions, are crucial contact elements in instruments and electrical appliances, primarily responsible for connecting or disconnecting circuits and carrying current. Ideal electrical contact materials must possess excellent physical, mechanical, electrical contact, chemical, and manufacturability properties. Currently, the most commonly used electrical contact materials are silver and silver-based composites, such as silver-oxide, silver-nickel, silver-copper, silver-cadmium, silver-carbon, and silver-tungsten alloys. These materials use a large amount of silver; they easily generate oxides such as silver oxide and tungsten oxide during switching, causing temperature rise; they are prone to sulfidation and wear, resulting in significant lifespan fluctuations as electrical contact materials. Furthermore, due to the very limited annual production and extremely high price of silver, the cost of contact materials is very high. Therefore, finding inexpensive metals with good conductivity to replace silver in the preparation of electrical contact materials is of great significance.

[0003] Copper has similar electrical conductivity to silver and is inexpensive, making it a potential substitute for silver in contact materials. While copper possesses excellent electrical and thermal conductivity and corrosion resistance, its surface is easily oxidized when used as a low-voltage contact material. Furthermore, copper oxides have very low conductivity, and the contact resistance increases continuously with oxide formation. This results in significant heat generation during operation, leading to poor reliability and a severely compromised lifespan for the electrical contact switch. Therefore, copper and common copper alloys rarely meet the comprehensive performance requirements for electrical contact materials.

[0004] Currently, adding various components to electrical contact materials to form reinforcing phases can improve the material's hardness and resistance to arc erosion. Graphene, as a novel nanomaterial, possesses advantages such as high specific strength, high thermal conductivity, and high electrical conductivity, and its applications in the electronics and electrical engineering fields are receiving increasing attention. Graphene's numerous superior physicochemical properties make it a potential reinforcing phase material for high-performance composite materials, serving as a reinforcement material for metals to improve their strength and thermal stability. However, as a non-metallic material, graphene also suffers from poor wettability with metallic materials, and its poor interfacial bonding with metals affects the material's performance. Therefore, solving the problems of copper's easy oxidation and the interfacial bonding between the copper matrix and the non-metallic reinforcing phase is particularly important.

[0005] There are currently several methods for preparing copper-based electrical contact materials. For example, patent (CN110484803 A) discloses a mixed dispersion-reinforced copper-tungsten-chromium electrical contact material. However, since the graphene is not surface-treated, the interfacial bonding between the graphene and the copper substrate is inevitably poor. Patent (CN105609159 A) discloses a copper-plated graphene-reinforced copper-based electrical contact material and its preparation method. Although magnetron sputtering is used to plate the graphene with copper, magnetron sputtering is costly, making large-scale production difficult, and it also suffers from uneven plating and poor bonding. Summary of the Invention

[0006] Based on the technical problems existing in the background art, the present invention proposes a graphene-reinforced copper-based electrical contact material and its preparation method. By performing copper-based surface treatment on graphene, the problems of poor interfacial wetting between graphene and copper and easy oxidation of copper are effectively solved, so that the obtained electrical contact material has excellent mechanical, electrical conductivity and oxidation resistance properties.

[0007] The present invention proposes a graphene-reinforced copper-based electrical contact material, the raw materials of which, by mass percentage, include: 15-35% tungsten powder, 1-10% chromium powder, 1-5% molybdenum powder, 0.1-1% cerium oxide powder, 0.5-2% copper-based graphene powder, and the balance being copper powder.

[0008] In this invention, copper-based graphene powder is prepared by liquid-phase in-situ reduction. When used in copper-based electrical contact materials, graphene and copper can be bonded together by molecular-level interaction forces, resulting in a relatively good copper-graphene interface. The mechanical properties and antioxidant properties are significantly improved, while maintaining excellent electrical conductivity.

[0009] Preferably, the tungsten powder and molybdenum powder have a particle size of 1-10 μm, and the chromium powder has a particle size of 10-50 μm.

[0010] Preferably, the copper powder is electrolytic copper powder or atomized copper powder with a particle size of 40-80 μm.

[0011] Preferably, the cerium oxide powder is loaded onto the surface of graphene, which is obtained by amination of graphene followed by hydrothermal reaction with cerium salt;

[0012] Preferably, the graphene amination specifically involves condensing graphene oxide with ethylenediamine followed by a reduction reaction.

[0013] In this invention, when cerium oxide powder is loaded onto the surface of graphene, the graphene oxide is first condensed and reduced with ethylenediamine to graft amino groups onto the graphene surface. Then, when it undergoes a hydrothermal reaction with cerium salt, the affinity between cerium ions in the cerium salt and the amino groups helps to distribute cerium ions evenly on the graphene surface. After the hydrothermal reaction, highly active cerium oxide nanoparticles can be loaded onto the graphene surface, ensuring its mechanical and electrical improvement effect on copper-based electrical contact materials.

[0014] In this invention, loading cerium oxide powder onto the surface of graphene not only activates the graphene surface and improves the interfacial bonding force between graphene and the copper matrix, but also promotes the formation of carbides at the interface, thereby exerting a pinning reinforcement effect and further improving the mechanical properties of the obtained electrical contact material.

[0015] Preferably, the copper-based graphene powder is obtained by grafting polyvinylimidazole onto the surface of graphene oxide and then reducing it with copper salt.

[0016] Preferably, the grafting of polyvinylimidazole onto the surface of graphene oxide specifically involves esterifying and condensing graphene oxide with 2-bromoisobutyryl bromide, followed by polymerization with 1-vinylimidazole.

[0017] Preferably, the reducing agent in the reduction reaction is at least one of ascorbic acid, formaldehyde, or hydrazine hydrate;

[0018] Preferably, the reduction reaction is carried out at a temperature of 100-150°C for 6-12 hours.

[0019] In this invention, when preparing copper-based graphene powder using the liquid-phase reduction method, polyvinylimidazole is pre-grafted onto the graphene surface. When it undergoes a liquid-phase reduction reaction with copper salt, on the one hand, the complexation effect of polyvinylimidazole on copper ions is utilized to provide abundant binding sites for the subsequent loading of copper on the graphene surface. On the other hand, the good dispersion effect of polyvinylimidazole is utilized to promote the reduction of copper salt to form spherical copper nanoparticles, which grow uniformly on the graphene surface. The resulting copper-based graphene powder has a complete structure, high activity, and no introduction of other impurities such as copper oxide and cuprous oxide.

[0020] In this invention, the loading of copper nanoparticles on copper-based graphene powder not only greatly enhances the interfacial bonding force between graphene and copper matrix during the subsequent powder metallurgy forming process, but also significantly improves the minimum tensile strength between grain boundaries of the resulting copper-based electrical contact material. At the same time, the enhanced interfacial bonding force also weakens the electron interface scattering effect, thereby improving the conductivity.

[0021] The present invention also proposes a method for preparing the above-mentioned graphene-reinforced copper-based electrical contact material, comprising the following steps:

[0022] S1. Tungsten powder, chromium powder, molybdenum powder, cerium oxide powder, copper-based graphene powder and copper powder are mixed and then ball-milled to obtain a mixed powder.

[0023] S2. After molding the mixed powder, it is then sintered at high temperature to obtain the graphene-reinforced copper-based electrical contact material.

[0024] Preferably, in step S1, the ball mill rotates at a speed of 100-500 r / min for 1-3 h.

[0025] Preferably, in step S2, the pressure of the compression molding is 600-800 MPa.

[0026] Preferably, in step S2, the high-temperature sintering temperature is 1000-1300℃ and the time is 1-2h.

[0027] This invention provides a graphene-reinforced copper-based electrical contact material and its preparation method. The copper-based electrical contact material uses copper as the matrix, which is cheaper and more abundant than silver. Tungsten powder, chromium powder, molybdenum powder, and cerium oxide powder are simultaneously added to the copper matrix to improve the material's resistance to arc erosion and its resistance to welding. Copper-based graphene is added, and copper nanoparticles are loaded onto the graphene through an in-situ chemical reduction reaction. This serves as a medium to increase the interaction force between the graphene and copper powder, significantly improving the interfacial force between the copper powder and graphene. The resulting electrical contact material also exhibits excellent comprehensive performance. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the grafted polyvinylimidazole graphene oxide described in Embodiment 1 of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0030] Example 1

[0031] This embodiment proposes a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0032] (1) Preparation of copper-based graphene powder:

[0033] Flake graphite (average particle size of 25 μm) and sodium nitrate were added to concentrated sulfuric acid at a mass ratio of 1:0.2. After stirring in an ice bath for 1 h, potassium permanganate was added at a mass ratio of 1:0.8. After stirring in an ice bath for 2 h, hydrogen peroxide (5 wt%) was added for reduction. The mixture was then filtered, washed with water, and dried to obtain graphene oxide.

[0034] The graphene oxide was ultrasonically dispersed in dichloromethane, and then 2-bromoisobutyryl bromide and triethylamine were added. The mass ratio of graphene oxide, 2-bromoisobutyryl bromide, and triethylamine was 1:0.1:0.5. The mixture was stirred for 6 hours under nitrogen protection, then hydrogen gas was introduced, and the temperature was raised to 90°C and stirred for 4 hours. The mixture was then filtered, washed, and dried to obtain brominated graphene. The brominated graphene was then added to N,N-dimethylformamide, and the mass ratio of brominated graphene to 1-vinylimidazole, cuprous bromide, and pentamethyldiethylenetriamine was 1:0.5:0.05:0.1. The mixture was stirred for 3 hours under nitrogen protection, and then filtered, washed, and dried to obtain grafted polyvinylimidazole graphene oxide.

[0035] The grafted polyvinylimidazole graphene oxide was added to deionized water and ultrasonically dispersed evenly. Copper acetate and ascorbic acid were added, with a mass ratio of 1:1.5:1. After stirring and dispersing evenly, sodium hydroxide solution (concentration of 1 mol / L) was added to adjust the pH to 11. The mixture was then subjected to hydrothermal reaction at 120℃ for 6 hours. After filtration, washing, and drying, the copper-based graphene powder was obtained.

[0036] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0037] The mixture of 25wt% tungsten powder (average particle size 3.5μm), 5wt% chromium powder (average particle size 42μm), 3wt% molybdenum powder (average particle size 3μm), 0.5wt% cerium oxide powder (average particle size 0.5μm), 65.5wt% electrolytic copper powder (average particle size 67μm) and 1wt% copper-based graphene powder was added to a ball mill jar and ball milled at 300 r / min for 2 h under argon protection to obtain a mixed powder.

[0038] The mixed powder was transferred into a graphite mold and molded at 700 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1200℃ for 1.5 h. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 h to obtain the graphene-reinforced copper-based electrical contact material.

[0039] Example 2

[0040] This embodiment proposes a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0041] (1) The preparation of copper-based graphene powder is as described in Example 1;

[0042] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0043] 15 wt% of tungsten powder (average particle size 3.5 μm), 10 wt% of chromium powder (average particle size 42 μm), 1 wt% of molybdenum powder (average particle size 3 μm), 1 wt% of cerium oxide powder (average particle size 0.5 μm), 72.5 wt% of electrolytic copper powder (average particle size 67 μm) and 0.5 wt% of the above-mentioned copper-based graphene powder were mixed and added to a ball mill jar. The mixture was ball milled at 100 r / min for 3 h under argon protection to obtain a mixed powder.

[0044] The mixed powder was transferred into a graphite mold and molded at 600 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1300℃ for 1 hour. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 hours to obtain the graphene-reinforced copper-based electrical contact material.

[0045] Example 3

[0046] This embodiment proposes a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0047] (1) The preparation of copper-based graphene powder is as described in Example 1;

[0048] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0049] The mixture of 35 wt% tungsten powder (average particle size 3.5 μm), 1 wt% chromium powder (average particle size 42 μm), 5 wt% molybdenum powder (average particle size 3 μm), 0.1 wt% cerium oxide powder (average particle size 0.5 μm), 56.9 wt% electrolytic copper powder (average particle size 67 μm) and 2 wt% copper-based graphene powder was added to a ball mill jar and ball milled at 500 r / min for 1 h under argon protection to obtain a mixed powder.

[0050] The mixed powder was transferred into a graphite mold and molded at 800 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1000℃ for 2 hours. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 hours to obtain the graphene-reinforced copper-based electrical contact material.

[0051] Example 4

[0052] This embodiment proposes a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0053] (1) The preparation of copper-based graphene powder is as described in Example 1;

[0054] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0055] 25wt% of tungsten powder (average particle size 3.5μm), 5wt% of chromium powder (average particle size 42μm), 3wt% of molybdenum powder (average particle size 3μm), 0.5wt% of cerium oxide powder, 65.5wt% of electrolytic copper powder (average particle size 67μm) and 1wt% of the above copper-based graphene powder were mixed and added to a ball mill jar. The mixture was ball milled at 300 r / min for 2 h under argon protection to obtain a mixed powder.

[0056] The cerium oxide powder described above is loaded onto the surface of graphene and is prepared by the following method:

[0057] Flake graphite (average particle size of 25 μm) and sodium nitrate were added to concentrated sulfuric acid at a mass ratio of 1:0.2. After stirring in an ice bath for 1 h, potassium permanganate was added at a mass ratio of 1:1.2. After stirring in an ice bath for 2 h, hydrogen peroxide (5 wt%) was added for reduction. The mixture was then filtered, washed with water, and dried to obtain graphene oxide.

[0058] The graphene oxide was added to N-methylpyrrolidone and ultrasonically dispersed evenly. Ethylenediamine was then added, with a mass ratio of graphene oxide to ethylenediamine of 1:0.1. The mixture was heated to 80°C and stirred for 4 hours. Hydrogen gas was then introduced, and the mixture was heated to 90°C and stirred for 6 hours. The mixture was then filtered, washed, and dried to obtain amino-based graphene.

[0059] The aminated graphene was added to deionized water and ultrasonically dispersed evenly. Cerium nitrate and ammonia were added, with the mass ratio of aminated graphene, cerium nitrate and ammonia being 1:15:1. The mixture was hydrothermally reacted at 180°C for 24 hours. After filtration, washing and drying, cerium oxide powder loaded on the surface of graphene was obtained.

[0060] The mixed powder was transferred into a graphite mold and molded at 700 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1200℃ for 1.5 h. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 h to obtain the graphene-reinforced copper-based electrical contact material.

[0061] Comparative Example 1

[0062] This comparative example presents a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0063] The mixture of 25wt% tungsten powder (average particle size 3.5μm), 5wt% chromium powder (average particle size 42μm), 3wt% molybdenum powder (average particle size 3μm), 0.5wt% cerium oxide powder (average particle size 0.5μm), 65.5wt% electrolytic copper powder (average particle size 67μm), and 1wt% flake graphite powder (average particle size 25μm) was added to a ball mill jar and ball-milled at 300 r / min for 2 h under argon protection to obtain a mixed powder.

[0064] The mixed powder was transferred into a graphite mold and molded at 700 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1200℃ for 1.5 h. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 h to obtain the graphene-reinforced copper-based electrical contact material.

[0065] Comparative Example 2

[0066] This comparative example presents a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0067] (1) Preparation of copper-based graphene powder:

[0068] Flake graphite (average particle size of 25 μm) and sodium nitrate were added to concentrated sulfuric acid at a mass ratio of 1:0.2. After stirring in an ice bath for 1 h, potassium permanganate was added at a mass ratio of 1:0.8. After stirring in an ice bath for 2 h, hydrogen peroxide (5 wt%) was added for reduction. The mixture was then filtered, washed with water, and dried to obtain graphene oxide.

[0069] The graphene oxide was added to dichloromethane and ultrasonically dispersed evenly. Hydrogen gas was introduced, and the mixture was heated to 90°C and stirred for 4 hours. The mixture was then filtered, washed, and dried to obtain reduced graphene oxide.

[0070] The reduced graphene oxide was added to deionized water and ultrasonically dispersed evenly. Copper acetate and ascorbic acid were added, with a mass ratio of reduced graphene oxide, copper acetate and ascorbic acid of 1:1.5:1. After stirring and dispersing evenly, sodium hydroxide solution (concentration of 1 mol / L) was added to adjust the pH to 11. The mixture was then subjected to hydrothermal reaction at 120℃ for 6 hours. After filtration, washing and drying, the copper-based graphene powder was obtained.

[0071] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0072] The mixture of 25wt% tungsten powder (average particle size 3.5μm), 5wt% chromium powder (average particle size 42μm), 3wt% molybdenum powder (average particle size 3μm), 0.5wt% cerium oxide powder (average particle size 0.5μm), 65.5wt% electrolytic copper powder (average particle size 67μm) and 1wt% copper-based graphene powder was added to a ball mill jar and ball milled at 300 r / min for 2 h under argon protection to obtain a mixed powder.

[0073] The mixed powder was transferred into a graphite mold and molded at 700 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1200℃ for 1.5 h. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 h to obtain the graphene-reinforced copper-based electrical contact material.

[0074] Comparative Example 3

[0075] This comparative example presents a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0076] (1) Preparation of copper-based graphene powder:

[0077] Flake graphite (average particle size of 25 μm) and sodium nitrate were added to concentrated sulfuric acid at a mass ratio of 1:0.2. After stirring in an ice bath for 1 h, potassium permanganate was added at a mass ratio of 1:0.8. After stirring in an ice bath for 2 h, hydrogen peroxide (5 wt%) was added for reduction. The mixture was then filtered, washed with water, and dried to obtain graphene oxide.

[0078] The graphene oxide was added to dichloromethane and ultrasonically dispersed evenly. Hydrogen gas was introduced, and the mixture was heated to 90°C and stirred for 4 hours. The mixture was then filtered, washed, and dried to obtain reduced graphene oxide.

[0079] The reduced graphene oxide was added to deionized water and ultrasonically dispersed evenly. Copper acetate, ascorbic acid, and polyvinylimidazole (PVI) were then added, with a mass ratio of 1:1.5:1:0.5. After stirring and dispersing evenly, sodium hydroxide solution (1 mol / L) was added to adjust the pH to 11. The mixture was then subjected to hydrothermal reaction at 120°C for 6 hours. After filtration, washing, and drying, the copper-based graphene powder was obtained.

[0080] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0081] The mixture of 25wt% tungsten powder (average particle size 3.5μm), 5wt% chromium powder (average particle size 42μm), 3wt% molybdenum powder (average particle size 3μm), 0.5wt% cerium oxide powder (average particle size 0.5μm), 65.5wt% electrolytic copper powder (average particle size 67μm) and 1wt% copper-based graphene powder was added to a ball mill jar and ball milled at 300 r / min for 2 h under argon protection to obtain a mixed powder.

[0082] The mixed powder was transferred into a graphite mold and molded at 700 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1200℃ for 1.5 h. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 h to obtain the graphene-reinforced copper-based electrical contact material.

[0083] Comparative Example 4

[0084] This comparative example presents a method for preparing a graphene-reinforced copper-based electrical contact material, specifically including:

[0085] (1) The preparation of copper-based graphene powder is as described in Example 1;

[0086] (2) Preparation of graphene-reinforced copper-based electrical contact materials:

[0087] 25wt% of tungsten powder (average particle size 3.5μm), 5wt% of chromium powder (average particle size 42μm), 3wt% of molybdenum powder (average particle size 3μm), 0.5wt% of cerium oxide powder, 65.5wt% of electrolytic copper powder (average particle size 67μm) and 1wt% of the above copper-based graphene powder were mixed and added to a ball mill jar. The mixture was ball milled at 300 r / min for 2 h under argon protection to obtain a mixed powder.

[0088] The cerium oxide powder described above is loaded onto the surface of graphene and is prepared by the following method:

[0089] Flake graphite (average particle size of 25 μm) and sodium nitrate were added to concentrated sulfuric acid at a mass ratio of 1:0.2. After stirring in an ice bath for 1 h, potassium permanganate was added at a mass ratio of 1:1.2. After stirring in an ice bath for 2 h, hydrogen peroxide (5 wt%) was added for reduction. The mixture was then filtered, washed with water, and dried to obtain graphene oxide.

[0090] The graphene oxide was added to N-methylpyrrolidone and ultrasonically dispersed evenly. Hydrogen gas was introduced, the temperature was raised to 90°C, and the mixture was stirred for 6 hours. The mixture was then filtered, washed, and dried to obtain reduced graphene oxide.

[0091] The reduced graphene oxide was added to deionized water and ultrasonically dispersed evenly. Cerium nitrate and ammonia were added, with the mass ratio of reduced graphene oxide, cerium nitrate and ammonia being 1:15:1. The mixture was subjected to hydrothermal reaction at 180°C for 24 hours. After filtration, washing and drying, cerium oxide powder loaded on the surface of graphene was obtained.

[0092] The mixed powder was transferred into a graphite mold and molded at 700 MPa to obtain a blank. The blank was then sintered at high temperature under argon protection at 1200℃ for 1.5 h. After cooling to room temperature, the temperature was increased to 600℃ at a rate of 10℃ / min and held for 2 h to obtain the graphene-reinforced copper-based electrical contact material.

[0093] The density, conductivity, hardness, and oxidation resistance of the graphene-reinforced copper-based electrical contact materials obtained in the above embodiments and comparative examples were determined using the following methods:

[0094] The density of the electrical contact material was measured and calculated using Archimedes' displacement method with a hydrostatic balance; the conductivity of the electrical contact material was tested using a digital conductivity meter; the Brinell hardness of the electrical contact material was tested using a Brinell hardness tester according to GB / T231.1-2009; the tensile strength of the electrical contact material was tested using an electronic universal testing machine according to GBT228.1-2010; and the weight gain after oxidation of the electrical contact material at 400℃ for 20 hours was tested.

[0095] Table 1. Performance of the graphene-reinforced copper-based electrical contact materials described in the examples and comparative examples.

[0096]

[0097] As can be seen from the results in the table above, the electrical contact material described in this invention has excellent mechanical, electrical conductivity, and antioxidant properties.

[0098] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A graphene-reinforced copper-based electrical contact material, characterized in that, Its raw materials, by mass percentage, include: 15-35% tungsten powder, 1-10% chromium powder, 1-5% molybdenum powder, 0.1-1% cerium oxide powder or graphene-supported cerium oxide powder, 0.5-2% copper-based graphene powder, and the balance being copper powder; The copper-based graphene powder is obtained by grafting polyvinylimidazole onto the surface of graphene oxide and then reducing it with copper salt. Specifically, the graphene oxide surface grafted with polyvinylimidazolium is prepared by esterifying and condensing graphene oxide with 2-bromoisobutyryl bromide, followed by polymerization with 1-vinylimidazolium.

2. The graphene-reinforced copper-based electrical contact material according to claim 1, characterized in that, The tungsten powder and molybdenum powder have a particle size of 1-10 μm, and the chromium powder has a particle size of 10-50 μm.

3. The graphene-reinforced copper-based electrical contact material according to claim 1 or 2, characterized in that, The copper powder is electrolytic copper powder or atomized copper powder with a particle size of 40-80μm.

4. The graphene-reinforced copper-based electrical contact material according to claim 1 or 2, characterized in that, The graphene-supported cerium oxide powder is obtained by amination of graphene and hydrothermal reaction with cerium salt. The graphene amination specifically involves a condensation reaction between graphene oxide and ethylenediamine, followed by a reduction reaction.

5. The graphene-reinforced copper-based electrical contact material according to claim 1, characterized in that, The reducing agent for the reduction reaction is at least one of ascorbic acid, formaldehyde, or hydrazine hydrate. The reduction reaction is carried out at a temperature of 100-150℃ for 6-12 hours.

6. A method for preparing the graphene-reinforced copper-based electrical contact material according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Tungsten powder, chromium powder, molybdenum powder, cerium oxide powder or graphene-supported cerium oxide powder, copper-based graphene powder and copper powder are mixed and then ball-milled to obtain a mixed powder. S2. After molding the mixed powder, it is then sintered at high temperature to obtain the graphene-reinforced copper-based electrical contact material.

7. The method for preparing the graphene-reinforced copper-based electrical contact material according to claim 6, characterized in that, In step S1, the ball mill rotates at a speed of 100-500 r / min for 1-3 h.

8. The method for preparing the graphene-reinforced copper-based electrical contact material according to claim 6, characterized in that, In step S2, the pressure of the compression molding is 600-800 MPa.

9. The method for preparing the graphene-reinforced copper-based electrical contact material according to claim 6, characterized in that, In step S2, the high-temperature sintering temperature is 1000-1300℃ and the time is 1-2h.

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