Electric contact conductor and preparation method and application thereof

Abstract

The invention provides an electric contact conductor and a preparation method and application thereof. The electric contact conductor comprises a metal matrix and a coating on the surface of the metal matrix. The coating layer comprises a first coating layer and a second coating layer, the first coating layer and the second coating layer extend in the depth direction of the surface of the metal matrix, and the first coating layer and the second coating layer are connected in the width direction; the first coating layer is a metal and conductive particle mixed layer, and the second coating layer is a metal and graphene mixed layer. The coating layer of the electric contact conductor provided by the invention is composed of the first coating layer and the second coating layer which are connected in the width direction, so that the wear resistance of the coating layer is enhanced, and the coating layer with relatively high wear resistance is obtained; meanwhile, due to the fact that the conductive particles in the first coating and the graphene in the first coating have conductivity, the conductive effect is achieved, and the defect that the conductivity of the metal electroplated layer is insufficient is overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field, and relates to an electrical contact conductor, in particular to an electrical contact conductor, a preparation method thereof and an application thereof. Background Art

[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, making graphene have great application prospects in many aspects.

[0003] During the actual use of an electrical contact conductor, it needs to face the invasion of dust, rain, snow, water vapor, dirt, etc., the erosion of corrosive gases such as sulfur dioxide, hydrogen sulfide, nitrogen dioxide, etc., or oxygen corrosion, etc. These external actual conditions will cause the contact resistance of the electrical contact conductor to increase or corrode the electrical contact conductor, resulting in poor electrical conductivity, and ultimately facing the risk of arc burnout. The prior art increases an anti-corrosion film layer by electroplating on the surface of the electrical contact conductor, but the increase of the anti-corrosion film layer will cause the electrical conductivity of the electrical contact conductor to decrease. In the existing design, by improving the structural distribution of the anti-corrosion film, a part of the material with strong electrical conductivity in the anti-corrosion film is directly connected to the internal electrical contact conductor to play a conductive role, and the substance with strong electrical conductivity can also prevent corrosion, such as the addition of graphene, graphene oxide or carbon nanotubes, in the hope of both preventing the corrosion of the electrical contact conductor and reducing the electrical conductivity. Although this design can solve the corrosion problem of the electrical contact conductor under certain conditions, however, since the electrical contact conductor usually needs to be closed and opened, facing repeated impact and friction, and the life of this film design is short under the action of repeated impact and friction. When the protective film is worn to expose the internal electrical contact conductor material, it still faces the problems of corrosion or dirt pollution, and cannot fundamentally solve the complex use environment of the electrical contact conductor.

[0004] The prior art discloses a method for electroplating a silver-graphene composite material onto a substrate. The method includes preparing a plating bath, which contains: a dissolved water-soluble silver salt, dispersed graphene sheets, and an aqueous electrolyte, and the electrolyte contains a silver complexing agent, a cationic surfactant, and a pH adjusting compound. By means of the cationic surfactant and the pH adjusting compound, the ζ potential at the graphene - electrolyte interface in the plating bath is adjusted to be positive and is 10 - 30 mV. The method also includes applying a negative potential on the surface of the substrate to cause electrophoresis of the graphene sheets, and the graphene sheets and silver are co-deposited during their electroplating to form a silver-graphene composite material coating on the surface of the substrate. However, the silver-graphene composite material coating obtained by the method of electroplating the silver-graphene composite material onto the substrate has poor wear resistance and a short life under the action of repeated impact and friction.

[0005] In the prior art, a preparation method of a composite coating is also disclosed, including the following steps: using a composite plating solution as an electroplating solution, performing brush plating on the surface of a substrate to obtain a composite coating; wherein, the composite plating solution includes silver nitrate, graphene, and carbon nanotubes; the silver in the obtained composite coating has a cellular structure; graphene and carbon nanotubes are distributed on the surface of the cellular structure, and the thickness of the composite coating is 20 - 25 μm. Through the cooperation of carbon nanotubes and graphene to wrap and cover silver particles, the coating becomes denser, improving the sulfur resistance and arc ablation resistance of the composite coating. Similarly, although the composite coating prepared by the preparation method of the composite coating improves the corrosion resistance and conductivity to a certain extent, its wear resistance is poor and cannot meet the requirements of actual production practice.

[0006] There are certain defects in the electrocontact conductors in the prior art, and there is a problem that it is impossible to simultaneously have good conductivity and excellent wear resistance. Therefore, it is crucial to develop and design a new type of electrocontact conductor and its preparation method. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an electrocontact conductor, its preparation method and its application. The coating of the electrocontact conductor provided by the present invention is composed of a first coating and a second coating connected in the width direction, enhancing the corrosion resistance and wear resistance of the coating, thereby obtaining a coating with strong wear resistance; at the same time, since the conductive particles in the first coating and the graphene in the first coating both have conductivity, they also play a conductive role, making up for the weakness of insufficient conductivity of the metal plating layer.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides an electrocontact conductor, which includes a metal substrate and a coating on the surface of the metal substrate; the coating includes a first coating and a second coating, the first coating and the second coating extend along the depth direction of the metal substrate surface, and the first coating and the second coating are connected in the width direction; the first coating is a mixed layer of metal and conductive particles, and the second coating is a mixed layer of metal and graphene.

[0010] The coating of the electrocontact conductor provided by the present invention is composed of a first coating and a second coating connected in the width direction, enhancing the corrosion resistance and wear resistance of the coating, thereby obtaining a coating with strong wear resistance; at the same time, since the conductive particles in the first coating and the graphene in the first coating both have conductivity, they also play a conductive role, making up for the weakness of insufficient conductivity of the metal plating layer.

[0011] Preferably, the conductive particles include a first metal core, a first graphene layer wrapped outside the first metal core, a first metal layer wrapped outside the first graphene layer, and a second graphene layer wrapped outside the first metal layer, wherein the coverage rate of the second graphene layer on the surface of the first metal layer is 38-49%;

[0012] The particle size of the first metal core is 0.03-10 μm, the thickness of the first graphene layer is 0.175-0.25 nm, and the thickness of the first metal layer is 100-800 nm;

[0013] The material of the first metal core includes a metal element and / or an alloy, and the material of the first metal layer includes silver and / or copper.

[0014] In the present invention, the second graphene layer is wrapped around the outer part of the first metal layer by vapor deposition, and the coverage rate of the second graphene layer on the surface of the first metal layer is 38-49%, for example, it can be 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% or 49.5%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] The particle size of the first metal core in the present invention is 0.03 to 10 μm, for example, it can be 0.03 μm, 0.04 μm, 0.05 μm, 0.07 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, 7 μm or 10 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] In the present invention, the thickness of the first graphene layer is 0.175-0.25 nm, for example, it can be 0.175 nm, 0.18 nm, 0.185 nm, 0.19 nm, 0.20 nm, 0.21 nm, 0.22 nm, 0.23 nm, 0.24 nm or 0.25 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In the present invention, the thickness of the first metal layer is 100-800nm, for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm or 800nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] The metal element in the present invention includes any one of nickel, copper or silver.

[0019] The alloy described in the present invention includes any one or a combination of at least two of nickel alloy, cobalt alloy, copper alloy, silver alloy, chromium alloy, zinc alloy or tin alloy. Typical but non-limiting combinations include the combination of nickel alloy and cobalt alloy, the combination of copper alloy and silver alloy, the combination of chromium alloy and zinc alloy, the combination of zinc alloy and tin alloy, or the combination of nickel alloy, cobalt alloy and copper alloy.

[0020] In a second aspect, the present invention provides a method for preparing the electrical contact conductor described in the first aspect. The preparation method includes:

[0021] (1) Using the substrate as the cathode, electro-depositing in a plating solution containing conductive particles to obtain a substrate with a composite coating attached to its surface;

[0022] (2) Using the substrate with the composite coating attached to its surface obtained in step (1) as the anode, performing anodic electrolytic deposition in an electrolyte solution containing graphene and conductive particles to obtain a substrate with a precursor coating attached to its surface;

[0023] (3) Subjecting the substrate with the precursor coating attached to its surface obtained in step (2) to hot press sintering to obtain the electrical contact conductor.

[0024] During the electro-deposition in step (1) of the present invention, the conductive particles form crystallization points in the electroplated layer, and the electroplated layer coats the conductive particles to form a composite coating. The formed composite coating not only has a strong bonding force with the substrate, but also has strong wear resistance and conductivity, and at the same time plays a role of fixing and positioning, preventing the graphene and conductive particles deposited in step (2) from partially detaching from the surface of the substrate, so that they cannot play a protective role.

[0025] At the beginning of the anodic electrolytic deposition in step (2) of the present invention, graphene and conductive particles are adsorbed to the surface of the composite coating by the oxidized metal ions in the composite coating and cover the composite coating; after the conductive particles are adsorbed to the anode, the outermost metal of the conductive particles is anodically oxidized to form new metal ions, which continue to adsorb graphene and conductive particles, and finally a second composite coating is formed in the gaps in the composite coating.

[0026] In step (3) of the present invention, hot press sintering reduces the internal gaps of the coating. After hot press sintering, a first coating and a second coating connected in the width direction are obtained. The connection between the first coating and the second coating is relatively tight, and the structures of the first coating and the second coating are relatively dense, thereby enhancing the overall performance of the coating.

[0027] The preparation method provided by the present invention carries out electrodeposition in a plating solution containing conductive particles to form a composite coating, and then uses a substrate with the composite coating attached to the surface as an anode, and fills graphene and conductive particles in the gaps of the composite coating by anodic electrolytic deposition to form a second composite coating, and then performs hot pressing and sintering to finally form a first coating and a second coating connected in the width direction on the surface of the substrate. Under the premise of not affecting the conductivity of the substrate, the coating has both good anti-corrosion effect and strong wear resistance.

[0028] Preferably, the conductive particles in step (2) include a second metal core, a third graphene layer wrapped outside the second metal core, and a second metal layer partially wrapped outside the third graphene layer, and the coverage rate of the second metal layer on the surface of the third graphene layer is 30-40%;

[0029] The particle size of the second metal core is 500nm-40μm, the third graphene layer includes 3-8 layers of graphene, and the thickness of the second metal layer is 10-25nm;

[0030] The material of the second metal core includes a metal element and / or an alloy, and the material of the second metal layer includes silver and / or copper.

[0031] In the present invention, the coverage rate of the second metal layer on the surface of the third graphene layer is 30-40%, for example, it can be 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] The particle size of the second metal core in the present invention is 500nm to 40μm, for example, it can be 500nm, 700nm, 1μm, 2μm, 5μm, 10μm, 20μm or 40μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] The third graphene layer in the present invention includes 3 to 8 graphene layers, for example, 3, 4, 5, 6, 7 or 8 layers, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] The thickness of the second metal layer in the present invention is 10 to 25 nm, for example, it can be 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm or 25 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the concentration of the conductive particles in the plating solution in step (1) is 0.06 - 1.2 g / L;

[0036] The plating solution includes any one of silver plating solution, copper plating solution or nickel plating solution;

[0037] When the plating solution is a silver plating solution, the concentration of silver ions is 60 - 90 g / L, the pH value is 8 - 10, the temperature is 16 - 24 °C, and the current density of the electrodeposition is 0.8 - 0.9 A / dm 2 .

[0038] When the plating solution is a nickel plating solution, the concentration of nickel ions is 300 - 320 g / L, the pH is 4.0 - 5, the temperature is 40 - 55 °C, and the current density of the electrodeposition is 0.8 - 0.9 A / dm 2 .

[0039] In step (1) of the present invention, the concentration of the conductive particles in the plating solution is 0.06 - 1.2 g / L. For example, it can be 0.06 g / L, 0.07 g / L, 0.08 g / L, 0.09 g / L, 0.1 g / L, 0.11 g / L or 0.12 g / L, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0040] When the plating solution in the present invention is a silver plating solution, the concentration of silver ions is 60 - 90 g / L. For example, it can be 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L or 90 g / L, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0041] When the plating solution in the present invention is a silver plating solution, the pH value is 8 - 10. For example, it can be 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8 or 10, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0042] When the plating solution in the present invention is a silver plating solution, the temperature is 16 - 24 °C. For example, it can be 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 24 °C, 23 °C or 24 °C, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0043] When the plating solution in the present invention is a silver plating solution, the current density of the electrodeposition is 0.8 - 0.9 A / dm 2 , for example, it can be 0.8 A / dm 2 , 0.81 A / dm 2 , 0.82 A / dm 2 , 0.83 A / dm 2, 0.84 A / dm 2 , 0.85 A / dm 2 , 0.86 A / dm 2 , 0.87 A / dm 2 or 0.8 A / dm 2 , but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0044] When the plating solution in the present invention is a nickel plating solution, the concentration of nickel ions is 300 - 320 g / L. For example, it can be 300 g / L, 302 g / L, 305 g / L, 307 g / L, 310 g / L, 312 g / L, 315 g / L, 317 g / L or 320 g / L. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0045] When the plating solution in the present invention is a nickel plating solution, the pH is 4.0 - 5.0. For example, it can be 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 or 5.0. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0046] When the plating solution in the present invention is a nickel plating solution, the temperature is 40 - 55 °C. For example, it can be 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, 52 °C, 54 °C or 55 °C. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0047] When the plating solution in the present invention is a nickel plating solution, the current density of the electro - deposition is 0.8 - 0.9 A / dm 2 , for example, it can be 0.8 A / dm 2 , 0.81 A / dm 2 , 0.82 A / dm 2 , 0.83 A / dm 2 , 0.84 A / dm 2 , 0.85 A / dm 2 , 0.86 A / dm 2 , 0.87 A / dm 2 , 0.88 A / dm 2 , 0.89 A / dm 2 or 0.9 A / dm 2 , but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0048] Preferably, the plating solution further includes a first dispersant with a concentration of 1.3 to 3.4 g / L. The first dispersant includes any one or a combination of at least two of N-acyl amino acid salts, sulfonated fatty amides, substituted amides of alkyl phosphates, or sulfonated esters of dicarboxylic acids;

[0049] During the electroplating, stirring and ultrasonic treatment are carried out simultaneously. The rotation speed of the stirring is 510 to 625 r / min, and the frequency of the ultrasonic treatment is 25 to 32 kHz.

[0050] In the present invention, the plating solution further includes a first dispersant with a concentration of 1.3 to 3.4 g / L. For example, it can be 1.3 g / L, 1.5 g / L, 1.7 g / L, 1.9 g / L, 2 g / L, 2.2 g / L, 2.4 g / L, 2.6 g / L, 2.8 g / L, 3.0 g / L, 3.2 g / L or 3.4 g / L, but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0051] In the present invention, the first dispersant includes any one or a combination of at least two of N-acyl amino acid salts, sulfonated fatty amides, substituted amides of alkyl phosphates, or sulfonated esters of dicarboxylic acids. Typical but non-limiting combinations include the combination of N-acyl amino acid salts and sulfonated fatty amides, the combination of substituted amides of alkyl phosphates and sulfonated esters of dicarboxylic acids, or the combination of N-acyl amino acid salts, sulfonated fatty amides and substituted amides of alkyl phosphates.

[0052] In the present invention, the rotation speed of the stirring is 510 to 625 r / min. For example, it can be 510 r / min, 520 r / min, 530 r / min, 540 r / min, 550 r / min, 5600 r / min, 570 r / min, 580 r / min, 590 r / min, 600 r / min, 610 r / min, 620 r / min or 625 r / min, but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0053] In the present invention, the frequency of the ultrasonic treatment is 25 to 32 kHz. For example, it can be 25 kHz, 26 kHz, 27 kHz, 28 kHz, 29 kHz, 30 kHz, 31 kHz or 32 kHz, but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0054] Preferably, the composite coating described in step (1) has a coral reef shape and a thickness of 5 - 850 μm. For example, it can be 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm or 800 μm. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0055] Preferably, in the electrolyte described in step (2), the concentration of graphene is 3.1 - 4.2 mg / L, the concentration of conductive particles is 1.8 - 4.3 g / L. The electrolyte further includes a conductive salt, and the pH of the electrolyte is 6 - 8;

[0056] The electrolyte further includes a second dispersant with a concentration of 1.3 - 3.4 g / L. The second dispersant includes any one or a combination of at least two of N-acyl amino acid salts, sulfonated fatty amides, substituted amides of alkyl phosphates, or sulfonated esters of dicarboxylic acids;

[0057] The voltage of the anodic electrodeposition in step (2) is 25 - 30 V, and the temperature is 30 - 35 °C.

[0058] In the present invention, the concentration of graphene in the electrolyte described in step (2) is 3.1 - 4.2 mg / L. For example, it can be 3.1 mg / L, 3.2 mg / L, 3.3 mg / L, 3.4 mg / L, 3.5 mg / L, 3.6 mg / L, 3.7 mg / L, 3.8 mg / L, 3.9 mg / L, 4.0 mg / L, 4.1 mg / L or 4.2 mg / L. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0059] In the present invention, the concentration of conductive particles in the electrolyte described in step (2) is 1.8 - 4.3 g / L. For example, it can be 1.8 g / L, 2.0 g / L, 2.2 g / L, 2.4 g / L, 2.6 g / L, 2.8 g / L, 3 g / L, 3.2 g / L, 3.4 g / L, 3.6 g / L, 3.8 g / L, 4.0 g / L, 4.2 g / L or 4.3 g / L. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0060] In the present invention, the pH of the electrolyte described in step (2) is 6 - 8. For example, it can be 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4, 7.6, 7.8 or 8. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0061] The electrolyte in step (2) of the present invention further includes a second dispersant with a concentration of 1.3 to 3.4 g / L. For example, it can be 1.3 g / L, 1.5 g / L, 1.7 g / L, 1.3 g / L, 1.9 g / L, 2.1 g / L, 2.3 g / L, 2.5 g / L, 2.7 g / L, 2.9 g / L, 3 g / L, 3.2 g / L or 3.4 g / L. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0062] The second dispersant in the present invention includes any one or a combination of at least two of N-acyl amino acid salts, sulfonated fatty amides, substituted amides of alkyl phosphates or sulfonated esters of dicarboxylic acids. Typical but non-limiting combinations include the combination of N-acyl amino acid salts and sulfonated fatty amides, the combination of substituted amides of alkyl phosphates and sulfonated esters of dicarboxylic acids, or the combination of N-acyl amino acid salts, sulfonated fatty amides and substituted amides of alkyl phosphates.

[0063] The conductive salt in the present invention can be, for example, a copper salt.

[0064] The voltage of the anodic electrolytic deposition in step (2) of the present invention is 25 to 30 V. For example, it can be 25 V, 26 V, 27 V, 28 V, 29 V or 30 V. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0065] The temperature of the anodic electrolytic deposition in step (2) of the present invention is 30 to 35 °C. For example, it can be 30 °C, 31 °C, 32 °C, 33 °C, 34 °C or 35 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0066] Preferably, between the anodic electrolytic deposition and the hot pressing sintering in step (3), there are also a first temperature rise and a second temperature rise carried out in sequence. The rate of the first temperature rise is 5 to 15 °C / min, and the end temperature is 450 to 600 °C; the rate of the second temperature rise is 15 to 25 °C / min, and the end temperature is 900 to 1100 °C;

[0067] The temperature of the hot pressing sintering in step (3) is the end temperature of the second temperature rise. The pressure of the hot pressing sintering is 25 to 35 MPa, the time is 40 to 50 min, and a mixed gas of hydrogen and a protective gas is used for pressurization in the hot pressing sintering.

[0068] In the present invention, the rate of the first temperature increase is 5 to 15 °C / min. For example, it can be 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min, 10 °C / min, 11 °C / min, 12 °C / min, 13 °C / min, 14 °C / min or 15 °C / min. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0069] In the present invention, the end temperature of the first temperature increase is 450 to 600 °C. For example, it can be 450 °C, 460 °C, 470 °C, 480 °C, 490 °C, 500 °C, 510 °C, 520 °C, 530 °C, 540 °C, 550 °C, 560 °C, 570 °C, 580 °C, 590 °C or 600 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0070] In the present invention, the rate of the second temperature increase is 15 to 25 °C / min. For example, it can be 15 °C / min, 16 °C / min, 17 °C / min, 18 °C / min, 19 °C / min, 20 °C / min, 21 °C / min, 22 °C / min, 23 °C / min, 24 °C / min or 25 °C / min. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0071] In the present invention, the end temperature of the first temperature increase is 900 to 1100 °C. For example, it can be 900 °C, 920 °C, 940 °C, 960 °C, 980 °C, 1000 °C, 1020 °C, 1040 °C, 1060 °C, 1080 °C or 1200 °C. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0072] In the present invention, the pressure of the hot press sintering is 25 to 35 MPa. For example, it can be 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa or 35 MPa. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0073] In the present invention, the time of the hot press sintering is 40 to 50 min. For example, it can be 40 min, 41 min, 42 min, 43 min, 44 min, 45 min, 46 min, 47 min, 48 min, 49 min or 50 min. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0074] In a third aspect, the present invention provides an application of the electrical contact conductor described in the first aspect, and the electrical contact conductor is applied to an electronic device or a circuit.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] (1) The cladding of the electrical contact conductor provided by the present invention is composed of a first cladding and a second cladding connected in the width direction, which enhances the corrosion resistance and wear resistance of the cladding, thereby obtaining a cladding with strong wear resistance; at the same time, since the conductive particles in the first cladding and the graphene in the first cladding are both conductive, they also play a conductive role, making up for the weakness of insufficient conductivity of the metal plating layer;

[0077] (2) The preparation method provided by the present invention is to perform electrodeposition in a plating solution containing conductive particles to form a composite coating, and then use the substrate with the composite coating attached to the surface as the anode. Through anodic electrolytic deposition, graphene and conductive particles are filled in the gaps of the composite coating to form a second composite coating, and then hot pressing and sintering are carried out. Finally, a cladding composed of a first cladding and a second cladding connected in the width direction is formed on the surface of the substrate. Without affecting the conductivity of the substrate, it has both good anti-corrosion effect and strong wear resistance. Specific embodiments

[0078] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0079] Example 1

[0080] This embodiment provides an electrical contact conductor, which includes a metal substrate and a cladding on the surface of the metal substrate;

[0081] The cladding includes a first cladding and a second cladding, the first cladding and the second cladding extend along the depth direction of the metal substrate surface, and the first cladding and the second cladding are connected in the width direction;

[0082] The first cladding is a mixed layer of silver and conductive particles, and the second cladding is a mixed layer of silver and graphene;

[0083] The conductive particles include a first silver core with a particle size of 5 μm, a first graphene layer with a thickness of 0.2 nm wrapped outside the first silver core, a first silver layer with a thickness of 450 nm wrapped outside the first graphene layer, and a second graphene layer partially wrapped outside the first silver layer, and the coating rate of the second graphene layer on the surface of the first silver layer is 43%.

[0084] The preparation method of the electrical contact conductor includes:

[0085] (1) Using the substrate as the cathode, electro-deposit in a silver plating solution containing conductive particles with a concentration of 0.6 g / L. During the electro-deposition, stirring and ultrasonic treatment are carried out simultaneously. The rotation speed of the stirring is 560 r / min, and the frequency of the ultrasonic treatment is 28 kHz, to obtain a substrate with a coral reef-shaped composite coating with a thickness of 400 μm attached to its surface;

[0086] The concentration of silver ions in the silver plating solution is 75 g / L, the pH value is 9, the temperature is 20 °C, and the current density of the electro-deposition is 0.85 A / dm 2 ; The silver plating solution also includes N-acyl amino acid salt with a concentration of 2.2 g / L;

[0087] (2) Using the substrate with the composite coating attached to its surface obtained in step (1) as the anode, in an electrolyte solution with a pH of 7 containing 3.6 mg / L of graphene, 3.1 g / L of conductive particles, and 2.3 g / L of sulfonated fatty amide, perform anodic electrolytic deposition at a voltage of 28 V at 32 °C to obtain a substrate with a precursor coating attached to its surface;

[0088] The conductive particles include a second silver core with a particle size of 10 μm, a third graphene layer wrapped outside the second silver core, the third graphene layer includes 5 layers of graphene, and a second silver layer with a thickness of 18 nm partially wrapped outside the third graphene layer. The coating rate of the second silver layer on the surface of the third graphene layer is 35%;

[0089] (3) Heat the substrate with the precursor coating attached to its surface obtained in step (2) to 520 °C at a rate of 10 °C / min, then heat it to 1000 °C at a rate of 10 °C / min, and then perform hot pressing sintering at a pressure of 30 MPa for 45 min. In the hot pressing sintering, a mixed gas of hydrogen and nitrogen is used for pressurization to obtain an electrical contact conductor.

[0090] Example 2

[0091] This example provides an electrical contact conductor, which includes a metal substrate and a coating on the surface of the metal substrate;

[0092] The coating includes a first coating and a second coating. The first coating and the second coating extend along the depth direction of the metal substrate surface, and the first coating and the second coating are connected in the width direction;

[0093] The first coating is a mixed layer of nickel and conductive particles, and the second coating is a mixed layer of copper and graphene;

[0094] The conductive particles include a first nickel core with a particle size of 0.03 μm, a first graphene layer with a thickness of 0.25 nm wrapped around the outside of the first nickel core, a first copper layer with a thickness of 800 nm wrapped around the outside of the first graphene layer, and a second graphene layer partially wrapping around the outside of the first copper layer, with the coverage rate of the second graphene layer on the surface of the first copper layer being 38%.

[0095] The preparation method of the electrical contact conductor includes:

[0096] (1) Using the substrate as the cathode, electroplating is carried out in a nickel plating solution containing conductive particles with a concentration of 1.2 g / L. Stirring and ultrasonic treatment are carried out synchronously during the electroplating. The rotation speed of the stirring is 625 r / min, and the frequency of the ultrasonic treatment is 32 kHz, to obtain a substrate with a coral reef-shaped composite coating with a surface attachment thickness of 850 μm;

[0097] The concentration of nickel ions in the nickel plating solution is 310 g / L, the pH is 4.5, the temperature is 48 °C, and the current density of the electroplating is 0.85 A / dm 2 ; The plating solution also includes N-acyl amino acid salt with a concentration of 3.4 g / L;

[0098] (2) Using the substrate with the surface-attached composite coating obtained in step (1) as the anode, in an electrolyte with a pH of 6 containing 3.1 mg / L of graphene, 1.8 g / L of conductive particles, and 1.3 g / L of alkyl phosphate substituted amide, anodic electrodeposition is carried out at 35 °C with a voltage of 25 V to obtain a substrate with a surface-attached precursor coating;

[0099] The conductive particles include a second copper core with a particle size of 500 nm, a third graphene layer wrapped around the outside of the second copper core, the third graphene layer includes 8 layers of graphene, and a second copper layer with a thickness of 10 nm partially wrapping around the outside of the third graphene layer, with the coverage rate of the second copper layer on the surface of the third graphene layer being 40%;

[0100] (3) Heating the substrate with the surface-attached precursor coating obtained in step (2) to 450 °C at a rate of 5 °C / min, then heating to 1100 °C at a rate of 15 °C / min, and then performing hot press sintering at a pressure of 25 MPa for 50 min. A mixed gas of hydrogen and argon is used for pressurization during the hot press sintering to obtain the electrical contact conductor.

[0101] Example 3

[0102] This example provides an electrical contact conductor, which includes a metal substrate and a coating on the surface of the metal substrate;

[0103] The cladding layer includes a first cladding layer and a second cladding layer. The first cladding layer and the second cladding layer extend along the depth direction of the surface of the metal matrix, and the first cladding layer is connected to the second cladding layer in the width direction;

[0104] The first cladding layer is a mixed layer of silver and conductive particles, and the second cladding layer is a mixed layer of copper and graphene;

[0105] The conductive particles include a first silver core with a particle size of 10 μm, a first graphene layer with a thickness of 0.175 nm wrapped outside the first silver core, a first silver layer with a thickness of 100 nm wrapped outside the first graphene layer, and a second graphene layer partially wrapped outside the first silver layer. The coating rate of the second graphene layer on the surface of the first silver layer is 49%.

[0106] The preparation method of the electrical contact conductor includes:

[0107] (1) Using the matrix as the cathode, electro-deposit in a silver plating solution containing conductive particles with a concentration of 0.06 g / L. During the electro-deposition, stirring and ultrasonic treatment are carried out simultaneously. The rotation speed of the stirring is 510 r / min, and the frequency of the ultrasonic is 25 kHz, to obtain a matrix with a coral reef-shaped composite coating layer with a thickness of 5 μm attached to the surface;

[0108] The concentration of silver ions in the silver plating solution is 90 g / L, the pH value is 10, the temperature is 24 °C, and the current density of the electro-deposition is 0.8 A / dm 2 ; The silver plating solution also includes a sulfonated ester of dicarboxylic acid with a concentration of 1.3 g / L;

[0109] (2) Using the matrix with the composite coating layer attached to the surface obtained in step (1) as the anode, in an electrolyte solution with a pH of 8 containing 4.2 mg / L of graphene, 4.3 g / L of conductive particles, and 3.4 g / L of N-acyl amino acid salt, carry out anodic electro-deposition at 30 °C with a voltage of 30 V to obtain a matrix with a precursor coating layer attached to the surface;

[0110] The conductive particles include a second copper core with a particle size of 40 μm, a third graphene layer wrapped outside the second copper core. The third graphene layer includes 3 layers of graphene, and a second copper layer with a thickness of 25 nm partially wrapped outside the third graphene layer. The coating rate of the second copper layer on the surface of the third graphene layer is 30%;

[0111] (3) Heat the matrix with the precursor coating layer attached to the surface obtained in step (2) to 600 °C at a rate of 15 °C / min, then heat it to 900 °C at a rate of 5 °C / min, and then carry out hot pressing sintering at a pressure of 35 MPa for 40 min. In the hot pressing sintering, a mixed gas of hydrogen and nitrogen is used for pressurization to obtain the electrical contact conductor.

[0112] Example 4

[0113] This example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the concentration of conductive particles in the silver plating solution in step (1) of the preparation method of the electrical contact conductor is 0.02 g / L.

[0114] Example 5

[0115] This example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the concentration of conductive particles in the silver plating solution in step (1) of the preparation method of the electrical contact conductor is 1.5 g / L.

[0116] Example 6

[0117] This example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the concentration of conductive particles in the electrolyte solution in step (2) of the preparation method of the electrical contact conductor is 1.4 g / L.

[0118] Example 7

[0119] This example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the concentration of conductive particles in the electrolyte solution in step (2) of the preparation method of the electrical contact conductor is 4.8 g / L.

[0120] Example 8

[0121] This example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the particle size of the first silver core in the conductive particles is 0.01 μm.

[0122] Example 9

[0123] This example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the particle size of the first silver core in the conductive particles is 15 μm.

[0124] Comparative Example 1

[0125] This comparative example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the conductive particles in the first coating are replaced with silver particles of the same size.

[0126] Comparative Example 2

[0127] This comparative example provides an electrical contact conductor, which is the same as Example 1 in all aspects except that the graphene in the second coating is replaced with silicon carbide of the same mass.

[0128] Comparative Example 3

[0129] This comparative example provides an electrical contact conductor, which is the same as Example 1 except that graphene in the second coating layer is omitted.

[0130] Comparative Example 4

[0131] This comparative example provides an electrical contact conductor, which is the same as Example 1 except that step (3) in the preparation method is omitted.

[0132] The electrical contact conductors obtained in Examples 1-9 and Comparative Examples 1-4 were subjected to conductivity tests and wear resistance tests;

[0133] The method for the conductivity test is as follows: The conductivity test was carried out by the method of T / CSTM00591-2022, and the conductivity obtained by the test is shown in Table 1;

[0134] The method for the wear resistance test is as follows: The wear resistance of the coating was detected by a steel wool friction tester, and the number of wear resistance times obtained by the test is shown in Table 1.

[0135] Table 1

[0136] Conductivity (%IACS) Number of wear-resistant cycles (times) Example 1 112 900 Example 2 107 890 Example 3 109 850 Example 4 94 812 Example 5 105 831 Example 6 101 819 Example 7 106 824 Example 8 108 815 Example 9 107 809 Comparative Example 1 105 803 Comparative Example 2 98 886 Comparative Example 3 95 796 Comparative Example 4 105 712

[0137] It can be seen from Table 1 that:

[0138] (1) The electrical contact conductors prepared in Examples 1-3 have strong conductivity and wear resistance, and thus have a long service life;

[0139] (2) By comparing Example 1 with Examples 4 and 5, it can be seen that the concentration of conductive particles in the silver plating solution in step (1) of the preparation method of the electrical contact conductor of the present invention will affect the performance of the electrical contact conductor; when the concentration of conductive particles is too small, it will lead to poor conductivity and wear resistance of the electrical contact conductor. This is because when the concentration of conductive particles is too low, the content of graphene and silver in the coating layer is relatively small, resulting in a decrease in conductivity. And because the content of graphene is small, it is difficult to achieve the effect of enhancing wear resistance; when the concentration of conductive particles is too large, it will also lead to poor conductivity and wear resistance of the electrical contact conductor. This is because when the concentration of conductive particles is too high, the required concentration of the dispersant is relatively high. If the dispersant is not increased, the conductive particles cannot be dispersed, resulting in the agglomeration of conductive particles, ultimately causing poor coating quality. If the dispersant is increased, it will lead to an increase in the ion migration resistance in the plating solution, which will poison the plating solution. And when the concentration exceeds a certain level, the dispersant cannot disperse the conductive particles, ultimately resulting in the inability to electroplate or a low density of the coating, leading to a decrease in both conductivity and wear resistance;

[0140] (3) It can be seen from the comparison between Example 1 and Examples 6 and 7 that the concentration of conductive particles in the electrolyte in step (2) of the preparation method of the electric contact conductor of the present invention will affect the performance of the electric contact conductor; when the concentration of conductive particles is too small, it will lead to a decrease in the conductivity of the electric contact conductor and poor wear resistance. This is because when the concentration of conductive particles is too low, the content of graphene and silver in the coating is relatively small, resulting in a decrease in conductivity. Moreover, due to the small content of graphene, it is difficult to achieve the effect of enhancing wear resistance; when the concentration of conductive particles is too large, it will also lead to a decrease in the conductivity and wear resistance of the electric contact conductor. This is because when the concentration of conductive particles is too high, the required concentration of the dispersant is relatively high. If the dispersant is not increased, the conductive particles cannot be dispersed, resulting in the agglomeration of conductive particles, and ultimately deteriorating the quality of the precursor coating. If the dispersant is increased, it will lead to an increase in the ion migration resistance in the electrolyte, poisoning the electrolyte. And when the concentration exceeds a certain level, the dispersant cannot disperse the conductive particles, ultimately resulting in the inability to perform anodic electrolytic deposition or a relatively low density of the precursor coating, leading to a decrease in both conductivity and wear resistance;

[0141] (4) It can be seen from the comparison between Example 1 and Examples 8 and 9 that the particle size of the first metal core in the conductive particles of the present invention will affect the performance of the electric contact conductor; when the particle size of the first metal core is too small, it will lead to a relatively small change in the conductivity of the electric contact conductor and a decrease in wear resistance. This is because when the particle size of the first metal core is too small, the size of the conductive particles will be too small. On the one hand, the too-small conductive particles will increase the difficulty of dispersion, resulting in the agglomeration of conductive particles and the inability to form a coating with high quality. On the other hand, the too-small conductive particles in the coating are difficult to enhance the hardness and wear resistance of the coating; when the particle size of the first metal core is too large, it will also lead to a relatively small change in the conductivity of the electric contact conductor and a decrease in wear resistance. This is because when the particle size of the first metal core is too large, the size of the conductive particles will be too large. When the size of the conductive particles is too large, they are unevenly distributed in the coating and usually show an agglomeration phenomenon. These agglomerates will form protrusions on the surface of the coating, which will have an adverse impact on the flatness, smoothness and density of the coating surface; in addition, when the size of the conductive particles in the coating is too large, many voids and air bubbles will be left, resulting in a rougher coating surface and increasing the risk of scratching and wear of the coating;

[0142] (5) It can be seen from the comparison between Example 1 and Comparative Example 1 that the structure of the conductive particles in the present invention will affect the performance of the electric contact conductor; when the conductive particles are replaced with silver particles of the same particle size, it will lead to a decrease in the conductivity of the electric contact conductor and poor wear resistance. This is because the conductivity of silver is lower than that of graphene. When the conductive particles are replaced with silver particles of the same particle size, it will lead to a decrease in the conductivity of the conductive particles, thus resulting in a decrease in the conductivity of the electric contact conductor. At the same time, since the graphene that plays a lubricating role in the conductive particles is omitted, the wear resistance decreases;

[0143] (6) It can be seen from the comparison between Example 1 and Comparative Examples 2 and 3 that the graphene in the second coating of the electric contact conductor described in the present invention will affect the performance of the electric contact conductor; when graphene is replaced with silicon carbide, the conductivity of the electric contact conductor will decrease and the wear resistance will become worse, because the conductivity and wear resistance of silicon carbide are both lower than those of graphene, so the enhancement effects on the conductivity and wear resistance of the electric contact conductor are both worse than those of graphene;; when graphene is omitted, the conductivity of the electric contact conductor will decrease and the wear resistance will become worse, because graphene has excellent conductivity and wear resistance, realizing the enhancement effects on the conductivity and wear resistance of the electric contact conductor. If graphene is omitted, the conductivity and wear resistance of the electric contact conductor will inevitably decrease;

[0144] (7) It can be seen from the comparison between Example 1 and Comparative Example 4 that the hot press sintering carried out after anodic electrolytic deposition in the present invention will affect the performance of the electric contact conductor; when the hot press sintering is omitted, the conductivity, corrosion resistance and wear resistance of the electric contact conductor will decrease, because in step (3) of the present invention, the hot press sintering reduces the internal gaps of the electric contact conductor and makes the structures of the conductive wear-resistant material, the second conductive particles and the porous coating more compact, thereby enhancing the overall performance of the electric contact conductor.

[0145] The above are only the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An electrical contact conductor, It is characterized in that The electrical contact conductor comprises a metal substrate and a coating on the surface of the metal substrate; The coating comprises a first coating and a second coating, wherein the first coating and the second coating extend in a depth direction of the surface of the metal substrate, and the first coating is connected to the second coating in a width direction; The first coating layer is a mixed layer of metal and conductive particles, and the second coating layer is a mixed layer of metal and graphene.

2. The electrical contact conductor according to claim 1, It is characterized in that The conductive particles include a first metal core, a first graphene layer wrapped outside the first metal core, a first metal layer wrapped outside the first graphene layer, and a second graphene layer partially wrapped outside the first metal layer, wherein the coverage rate of the second graphene layer on the surface of the first metal layer is 38-49%; The particle size of the first metal core is 0.03-10 μm, the thickness of the first graphene layer is 0.175-0.25 nm, and the thickness of the first metal layer is 100-800 nm; The material of the first metal core includes a metal element and / or an alloy, and the material of the first metal layer includes silver and / or copper.

3. A method for preparing the electrical contact conductor according to claim 1 or 2, It is characterized in that The preparation method comprises: (1) using the substrate as a cathode, performing electrodeposition in a plating solution containing conductive particles to obtain a substrate with a composite coating attached to the surface; (2) using the substrate with the composite coating attached to the surface obtained in step (1) as an anode, performing anodic electrolytic deposition in an electrolyte containing graphene and conductive particles to obtain a substrate with a precursor coating attached to the surface; (3) hot pressing and sintering the substrate with the precursor coating attached to the surface obtained in step (2) to obtain an electrical contact conductor.

4. The preparation method according to claim 3, It is characterized in that The conductive particles in step (2) include a second metal core, a third graphene layer wrapped outside the second metal core, and a second metal layer partially wrapped outside the third graphene layer, wherein the coverage of the second metal layer on the surface of the third graphene layer is 30-40%; The particle size of the second metal core is 500nm-40μm, the third graphene layer includes 3-8 layers of graphene, and the thickness of the second metal layer is 10-25nm; The material of the second metal core includes a metal element and / or an alloy, and the material of the second metal layer includes silver and / or copper.

5. The preparation method according to claim 3 or 4, It is characterized in that The concentration of the conductive particles in the plating solution in step (1) is 0.06 to 1.2 g / L; The plating solution includes any one of a silver plating solution, a copper plating solution or a nickel plating solution; The plating solution is a silver plating solution, the concentration of silver ions is 60 to 90 g / L, the pH value is 8 - 10, the temperature is 16 to 24 °C, and the current density of the electrodeposition is 0.8 to 0.9 A / dm 2 ; The plating solution is a nickel plating solution, the concentration of nickel ions is 300-320 g / L, the pH is 4.0-5, the temperature is 40-55 °C, and the current density of the electrodeposition is 0.8-0.9 A / dm 2 .

6. The preparation method according to any one of claims 3 to 5, It is characterized in that The plating solution also includes a first dispersant with a concentration of 1.3 to 3.4 g / L, wherein the first dispersant includes any one or a combination of at least two of N-acylamino acid salts, sulfonated fatty amides, substituted amides of alkyl phosphates, or sulfonated esters of dicarboxylic acids; During the electrodeposition, stirring and ultrasonic treatment are carried out simultaneously. The rotation speed of the stirring is 510 - 625 r / min, and the frequency of the ultrasonic treatment is 25 - 32 kHz.

7. The preparation method according to any one of claims 3 - 6, characterized in that, the shape of the composite coating in step (1) is coral reef - shaped, and the thickness is 5 - 850 μm.

8. The preparation method according to any one of claims 3 - 7, characterized in that, in step (2), the concentration of graphene in the electrolyte is 3.1 - 4.2 mg / L, the concentration of conductive particles is 1.8 - 4.3 g / L. The electrolyte further includes a conductive salt, and the pH of the electrolyte is 6 - 8; the electrolyte further includes a second dispersant with a concentration of 1.3 - 3.4 g / L. The second dispersant includes any one or a combination of at least two of N - acyl amino acid salts, sulfonated fatty amides, substituted amides of alkyl phosphates, or sulfonated esters of dicarboxylic acids; in step (2), the voltage for anodic electrodeposition is 25 - 30 V, and the temperature is 30 - 35 °C.

9. The preparation method according to any one of claims 3 - 8, characterized in that, between the anodic electrodeposition and hot - press sintering in step (3), there are also a first temperature rise and a second temperature rise carried out successively. The rate of the first temperature rise is 5 - 15 °C / min, and the end temperature is 450 - 600 °C; the rate of the second temperature rise is 15 - 25 °C / min, and the end temperature is 900 - 1100 °C; the temperature of the hot - press sintering in step (3) is the end temperature of the second temperature rise. The pressure of the hot - press sintering is 25 - 35 MPa, the time is 40 - 50 min, and a mixed gas of hydrogen and a protective gas is used for pressurization during the hot - press sintering.

10. An application of the electrical contact conductor according to claim 1 or 2, characterized in that, the electrical contact conductor is applied to electronic devices or circuits.