Preparation method of graphene high-conductivity contact line

Abstract

The invention discloses a preparation method of a graphene high-conductivity contact wire, which is characterized in that graphene agglomeration is reduced, the distribution uniformity of graphene in a copper matrix is improved and the formation of nano twin copper is promoted by introducing graphene into a contact wire product copper-based alloy and intermittently depositing pulse current by a pulse electrodeposition method. The strength and conductivity of the composite material are improved, the electrical performance of the material is improved to the maximum extent while the strength and hardness of the material are guaranteed, meanwhile, the graphene second phase can effectively improve the wear resistance of the contact wire in the using process and reduce the wear of the contact wire, the strength of the contact wire can reach 500 MPa or above, the conductivity is controlled to be 90% IACS or above, and the surface hardness of the contact wire can reach 85 HB or above. According to electrical performance estimation, the energy consumption of the contact network is predicted to be reduced by more than 10%, and the service life of the contact line is prolonged by more than one time and far exceeds that of other types of contact line products.

Description

TECHNICAL FIELD

[0001] The embodiment of the application relates to the technical field of contact wire, and in particular to a preparation method of a graphene high-conductivity contact wire. BACKGROUND

[0002] The contact wire is an important part of the traction power supply of the overhead contact system of the rail transit, and the conductivity of the contact wire directly affects the energy consumption of the whole overhead contact system. The annual energy consumption of the overhead contact system in 2023 reaches 80 billion kilowatt hours, and according to the development of the railway system, the peak power consumption of the overhead contact system in 2025 is expected to reach 100 billion kilowatt hours. At present, the most effective way to save energy is to reduce the resistance value of the overhead contact system and improve the conductivity of the overhead contact system.

[0003] At present, the way to reduce the resistance value of the overhead contact system can only be achieved by optimizing the material and reducing the resistivity of the material to reduce the resistance. The existing copper-based alloy has limited improvement means, and can only reduce the influence on the resistivity by introducing a second phase. The application aims to improve the hardness and strength of the copper-based alloy by introducing the graphene as the conductive second phase, and improve the conductivity of the copper-based alloy. On the basis of ensuring the mechanical and electrical properties of the raw material, the conductivity and wear resistance of the contact wire product are enhanced by introducing the graphene phase, the service life of the contact wire is improved, and the energy consumption of the overhead contact system is reduced. SUMMARY

[0004] Therefore, the embodiment of the application provides a preparation method of a graphene high-conductivity contact wire, which enhances the conductivity and wear resistance of the contact wire product by introducing the graphene phase.

[0005] In order to achieve the above purpose, the embodiment of the application provides the following technical scheme: According to the first aspect of the embodiment of the application, the embodiment of the application provides a preparation method of a graphene high-conductivity contact wire, and the preparation method comprises the following steps: Preparation of graphene / copper composite material by pulse complex electrodeposition; Mixing copper powder and silver powder to obtain copper-silver alloy powder, and then mixing the prepared graphene / copper composite material and the copper-silver alloy powder to obtain synthetic powder; Isostatic pressing and sintering of the synthetic powder to form an alloy blank; Hot forging of the sintered alloy blank to eliminate internal casting defects of the material; Pushing of the hot-forged alloy blank to refine the grain size of the material; Surface treatment of the pushed alloy blank to remove surface oxidation, cracking and extrusion defects of the material; Rolling of the surface-treated alloy blank to improve the strength and hardness of the material; Drawing and shaping of the rolled alloy blank to obtain a finished product contact wire.

[0006] Further, the graphene / copper composite material is prepared by pulse composite electrodeposition, specifically comprising: CuSO4 is used as the main salt, polysulfur organic sulfonate is used as the brightener, mercapto heterocyclic compound is used as the leveling agent, sodium dodecyl sulfate and hydrogen peroxide are used as the cuprous ion oxidant, and graphene is added; the current density, on-time, off-time and temperature are set; stirring and ultrasonic are performed to prevent graphene from agglomeration; and the graphene / copper composite material is obtained.

[0007] Further, the graphene / copper composite material is prepared by pulse composite electrodeposition, specifically comprising: CuSO4 is used as the main salt, 0.01-0.1 g / L polysulfur organic sulfonate is used as the brightener, 0.01-0.1 g / L mercapto heterocyclic compound is used as the leveling agent, 0.05-0.1 g / L sodium dodecyl sulfate and 1-10 mL / L hydrogen peroxide are used as the cuprous ion oxidant, and 0.5 g / L graphene is added; the current density is set to 500-1000 mA / , the on-time is set to 0.1-0.3 s, the off-time is set to 1-2 s, and the temperature is controlled to 20-25℃; stirring and ultrasonic are performed at 200-1000 rpm mechanical stirring + 10-40 kHz ultrasonic assistance.

[0008] Further, the copper powder and the silver powder are mixed to obtain a copper-silver alloy powder, and the prepared graphene / copper composite material is mixed with the copper-silver alloy powder to obtain a synthetic powder, specifically comprising: The Cu powder with a purity of >99.98% and a particle size of 500 mesh is mixed with the Ag powder with a purity of >99.99% and a particle size of 500 mesh at a ratio of 999:1 to prepare a copper-silver alloy powder; The prepared graphene / copper composite material is mixed into the prepared copper-silver alloy powder to obtain a synthetic powder.

[0009] Further, the synthetic powder is isostatic sintered to sinter an alloy blank, specifically comprising: The mixed alloy powder is isostatic sintered at a sintering temperature of 800℃, a pressure of 5MPa and a sintering time of 1h, and the mixed powder is sintered into a φ80mm rod.

[0010] Further, the sintered alloy blank is hot forged to eliminate internal casting defects of the material, specifically comprising: The sintered blank is heated to 500℃ for rotary forging, and the outer diameter is forged from φ80mm to φ70mm to eliminate internal casting defects of the material.

[0011] Further, the hot forged alloy blank is pushed to refine the internal grain size of the material, specifically comprising: The forged blank is preheated to 480 DEG C and kept for 30 minutes, and then put into the pushing equipment to push the blank into a φ30mm rod, refine the internal grain size of the material, and make the average grain size in the rod reach 0.03mm.

[0012] Further, the pushed alloy blank is subjected to surface treatment to remove the surface oxidation, cracking and extrusion defects of the material, specifically including: The extruded rod is subjected to roll straightening and skinning, and skinned 4 times with a skinning thickness of 1mm, so as to sufficiently remove the surface oxidation, cracking and extrusion defects of the material.

[0013] Further, the alloy blank after surface treatment is subjected to rolling to improve the strength and hardness of the material, specifically including: The skinned blank is subjected to rolling to make a φ20mm rod, and the strength of the material is improved through cold rolling.

[0014] Further, the rolled alloy blank is drawn to shape to obtain a finished contact line, specifically including: The rolled blank is drawn, and the drawing pass is 4 passes, so as to finally obtain the finished contact line.

[0015] Compared with the prior art, the preparation method of the graphene high-conductivity contact line provided by the application introduces graphene into the contact line product alloy material, greatly improves the strength and wear resistance of the material while reducing the conductivity of the material as much as possible, reduces the maintenance cost of the contact network, provides a new material selection for rail transit speedup, breaks the original processing technology, and provides a new alloy series. DETAILED DESCRIPTION

[0016] The application will be described in detail below with examples. It should be noted that the examples in the application and the features in the examples can be combined with each other without conflict.

[0017] The following detailed description is exemplary description, which is intended to provide further detailed description of the application. Unless otherwise specified, all technical terms used in the application have the same meaning as generally understood by those skilled in the art to which the application belongs. The terms used in the application are only for the description of the specific embodiments, and are not intended to limit the exemplary embodiments according to the application.

[0018] The embodiment of the present application proposes a preparation method of a graphene high-conductivity contact line. The graphene, Ag and Cu powder are mixed in a corresponding proportion, and then sintered, so that the ceramic powder is fully distributed in the copper and silver, and the purpose of full dispersion and uniform distribution is achieved. The specific steps are as follows: Step one, preparation of high-purity graphene / copper composite material: CuSO4 is used as the main salt, 0.01-0.1 g / L of polysulfur organic sulfonate is used as the brightener, 0.01-0.1 g / L of mercapto heterocyclic compound is used as the leveling agent, 0.05-0.1 g / L of sodium dodecyl sulfate, 1-10 mL / L of hydrogen peroxide is used as the cuprous ion oxidizing agent, 0.5 g / L of graphene, current density 500-1000 mA / , on time 0.1-0.3 s, off time 1-2 s, control temperature 20-25 degrees, stirring and ultrasonic auxiliary: 200-1000 rpm mechanical stirring + 10-40 kHz ultrasonic auxiliary, to prevent graphene agglomeration. Obtain graphene / copper composite material.

[0019] Step two, powdering The Cu powder with a purity of >99.98% and a particle size of 500 mesh is mixed with the Ag powder with a purity of >99.99% and a particle size of 500 mesh in a ratio of 999:1 to prepare a copper-silver alloy powder; the obtained graphene / copper composite material is mixed with the copper-silver alloy powder with a purity of 99.3% to obtain a synthesis powder.

[0020] Step three, sintering The mixed alloy powder is sintered by isostatic pressing, the sintering temperature is 800℃, the pressure is 5MPa, and the sintering time is 1h. The mixed powder is sintered into a φ80mm rod.

[0021] Step four, forging The sintered blank is heated to 500℃ for rotary forging, and the outer diameter is forged from φ80mm to φ70mm to eliminate internal casting defects of the material.

[0022] Step five, pushing The forged blank is preheated to 480℃ and kept for 30min, and then put into the pushing equipment, the blank is pushed into a φ30mm rod, and the internal grain size of the material is refined, so that the average grain size of the rod is 0.03mm.

[0023] Step six, surface treatment The extruded rod is straightened and skinned, and skinned 4 times, with a skin thickness of 1mm, to fully remove surface defects such as cracking and oxidation.

[0024] Step seven, rolling The peeled blank is rolled to form a φ20mm rod, and the material strength is improved by cold rolling.

[0025] Step eight, drawing The rolled blank is drawn, and the drawing pass is 4, finally the CTAH150 contact line product is obtained, the product strength is 500-520MPa, the 20℃ resistivity is 0.01900-0.01974Ωmm2 / m, and the Brinell hardness is 85-90HB.

[0026] The graphene is introduced into the contact line product copper-based alloy, the intermittent deposition of the pulse current is realized by the pulse electrodeposition method, the graphene agglomeration is reduced, the uniformity of the graphene in the copper matrix is improved, the formation of nano-twin copper is promoted, and the strength and conductivity of the composite material are improved. While ensuring the strength and hardness of the material, the electrical performance of the material is maximized, and the second phase of graphene can effectively improve the wear resistance of the contact line during use, reduce the wear of the contact line, and the strength can reach more than 500MPa, the conductivity is controlled to be more than 90%IACS, the surface hardness can reach more than 85HB, according to the electrical performance estimation, the overhead contact line energy consumption is expected to be reduced by more than 10%, the service life of the contact line is improved by more than 1 times, and it is far superior to other types of contact line products.

[0027] Finally, it should be noted that: the above examples are used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can be modified or replaced, without departing from the spirit and scope of the present application, any modification or equivalent replacement, which should be covered in the protection scope of the claims of the present application.

Claims

1. A method for preparing a graphene high-conductivity contact wire, characterized in that: The preparation method comprises: Preparation of graphene / copper composites by pulsed composite electrodeposition; The copper powder and the silver powder are fully mixed to obtain a copper-silver alloy powder, and the prepared graphene / copper composite material is then mixed with the copper-silver alloy powder to obtain a synthetic powder; isostatically pressing and sintering the synthesized powder into an alloy billet; hot forging the sintered alloy billet; The hot-forged alloy billet is pushed; The extruded alloy billet is subjected to surface treatment; The surface treated alloy billet is then rolled; The rolled alloy billet is formed by drawing to obtain the finished contact wire.

2. The method for preparing a graphene high-conductivity contact wire according to claim 1, characterized in that: Graphene / copper composite materials are prepared by pulse composite electrodeposition, specifically comprising: CuSO4 is used as the main salt, polysulfide organic sulfonate is used as the brightener, mercapto heterocyclic compound is used as the leveling agent, hydrogen peroxide is used as the cuprous ion oxidant, graphene and sodium dodecyl sulfate are added; the current density, on-time, off-time and temperature are set; stirring and ultrasound are performed to prevent graphene agglomeration; and a graphene / copper composite material is obtained.

3. The method for preparing a graphene high-conductivity contact wire according to claim 2, wherein: Graphene / copper composite materials are prepared by pulse composite electrodeposition, specifically comprising: CuSO4 was used as the main salt, 0.01-0.1 g / L polysulfide organic sulfonate was used as the brightener, 0.01-0.1 g / L mercapto heterocyclic compound was used as the leveling agent, 1-10 mL / L hydrogen peroxide was used as the cuprous ion oxidant, 0.5 g / L graphene and 0.05-0.1 g / L sodium dodecyl sulfate were added; the current density was set to 500-1000 mA / , on-time 0.1-0.3 s, off-time 1-2 s; control temperature 20-25℃; stirring and ultrasound: 200-1000 rpm mechanical stirring + 10-40 kHz ultrasonic assistance.

4. The method for preparing a graphene high-conductivity contact wire according to claim 1, wherein: The copper powder and the silver powder are fully mixed to obtain a copper-silver alloy powder, and the prepared graphene / copper composite material is then mixed with the copper-silver alloy powder to obtain a synthetic powder, specifically comprising: The copper-silver alloy powder is prepared by mixing Cu powder with a purity of more than 99.98% and a particle size of 500 mesh and Ag powder with a purity of more than 99.99% and a particle size of 500 mesh in a ratio of 999:1; The prepared graphene / copper composite material is then mixed into the prepared copper-silver alloy powder to obtain a synthetic powder.

5. The method for preparing a graphene high-conductivity contact wire according to claim 1, wherein: The synthetic powder is subjected to isostatic pressing and sintering to form an alloy billet, specifically including: The mixed alloy powder is subjected to isostatic pressing sintering at a sintering temperature of 800°C, a pressure of 5 MPa, and a sintering time of 1 hour, and the mixed powder is sintered into φ80 mm rods.

6. The method for preparing a graphene high-conductivity contact wire according to claim 1, wherein: The sintered alloy billet is hot forged, specifically comprising: The sintered blank was heated to 500°C and rotary forged to reduce the outer diameter from φ80mm to φ70mm.

7. The method for preparing a graphene high-conductivity contact wire according to claim 1, characterized in that: The hot forged alloy billet is pushed and extruded, specifically including: The forged billet is preheated to 480°C and kept warm for 30 minutes. It is then placed in an extrusion device and extruded into a φ30mm rod, so that the average grain size inside the rod reaches 0.03mm.

8. The method for preparing a graphene high-conductivity contact wire according to claim 1, characterized in that: The extruded alloy billet is subjected to surface treatment, specifically including: The extruded rods are rolled straight and peeled 4 times with a peeling thickness of 1mm to remove oxidation, cracking and extrusion defects on the material surface.

9. The method for preparing a graphene high-conductivity contact wire according to claim 1, characterized in that: The alloy billet after surface treatment is rolled, specifically including: The peeled billet is rolled into φ20mm bars, and the material strength is increased through cold rolling.

10. The method for preparing a graphene high-conductivity contact wire according to claim 1, characterized in that: The rolled alloy billet is drawn and formed to obtain a finished contact wire, specifically including: The rolled billet is drawn with 4 drawing passes to finally obtain the finished contact line.