Micro-nano hybrid filler synergistically enhanced pantograph slide plate and preparation method thereof

Abstract

The invention relates to a micro-nano hybrid filler synergistically enhanced pantograph slide plate and a preparation method thereof, and relates to the field of composites.The preparation method comprises the steps that graphene oxide is modified through ethidene diamine, and modified graphene oxide is obtained; the method comprises the following steps: modifying a carbon nano tube by adopting an acid solution to obtain a modified carbon nano tube; the preparation method comprises the following steps: modifying nano silicon dioxide by adopting a silane coupling agent to obtain modified silicon dioxide; mixing the modified graphene oxide, the modified nanotube and the modified silicon dioxide, and carrying out electrostatic self-assembly to obtain a micro-nano hybrid filler; the micro-nano hybrid filler, pitch coke, graphite powder and coal pitch are mixed, kneaded, rolled, pressed and sintered, and the pantograph slide plate synergistically enhanced by the micro-nano hybrid filler is obtained. The micro-nano hybrid filler is prepared from the modified graphene oxide, the carboxyl functionalized carbon nanotubes and the modified nano silicon dioxide through electrostatic self-assembly, so that the bending resistance, the compressive strength, the electric conductivity, the heat conductivity and other properties of the pantograph slide plate are improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers and a preparation method thereof. Background Art

[0002] The pantograph skateboard has gone through several development stages, including metal skateboard, pure carbon skateboard, powder metallurgy skateboard, metal-impregnated carbon skateboard and new composite skateboard. Carbon-based composite materials have excellent properties such as low density, high strength, wear resistance and high temperature resistance, showing broad application prospects in the pantograph skateboard of high-speed trains. However, carbon-based composite materials generally have problems such as pores, cracks, and weak interface bonding, which affect the performance of the material, making its resistivity large and its mechanical properties low, and cannot fully meet the use requirements of high-speed train pantograph skateboards. Therefore, it is urgent to develop carbon-based composite pantograph skateboards with excellent mechanical and electrical properties to meet the service performance requirements of equipment in the field of rail transportation. Summary of the invention

[0003] The purpose of the present invention is to provide a pantograph slide plate reinforced with micro-nano hybrid fillers and a preparation method thereof to improve the above problems. In order to achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; The carbon nanotubes are modified by using an acid solution to obtain modified carbon nanotubes; The nano-silicon dioxide is modified by using a silane coupling agent to obtain modified silicon dioxide; The modified graphene oxide, modified nanotubes and modified silicon dioxide are mixed and subjected to electrostatic self-assembly to obtain a micro-nano hybrid filler; The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed, kneaded, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0004] Optionally, the particle size of the nano-silicon dioxide is less than or equal to 20 nm; the outer diameter of the carbon nanotube is 50-80 nm, and the length is 5-10 μm.

[0005] Optionally, the method of modifying graphene oxide by using ethylenediamine to obtain modified graphene oxide comprises: Adding graphene oxide to N,N-dimethylformamide for dispersion, and then adding N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine for further dispersion to obtain a graphene dispersion; The graphene dispersion is reacted at 55-65° C. for 6-10 hours, and after the reaction is completed, the modified graphene oxide is obtained by filtering, washing and drying.

[0006] Optionally, the step of modifying the carbon nanotubes with an acid solution includes: The carbon nanotubes are added into a mixed solution of concentrated nitric acid and concentrated sulfuric acid, mixed and reacted at 40-60° C. for 3-5 hours, and then filtered and dried.

[0007] Optionally, the modification of nano-silicon dioxide by using a silane coupling agent includes: Pre-soaking nano-silicon dioxide in anhydrous ethanol for 30-60 minutes, and then stirring and dispersing to obtain a silicon dioxide dispersion; The silicon dioxide dispersion is stirred, and water is added dropwise thereto, and then a mixed solution of a silane coupling agent and ethanol is added dropwise to the silicon dioxide dispersion, and the mixture is stirred and reacted at 60-80° C. for 6-10 hours, and then dried after centrifugal washing.

[0008] Optionally, the mass ratio of the asphalt coke, graphite powder, coal tar pitch and micro-nano hybrid rice filler is 65:(2-5):(23-27):(1-3).

[0009] Optionally, the modified graphene oxide, modified carbon nanotubes and modified silicon dioxide are mixed and subjected to electrostatic self-assembly to obtain a micro-nano hybrid filler, comprising: The modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide are respectively added into water and dispersed for 1-1.5 hours to obtain a first suspension, a second suspension, and a third suspension, respectively; The first suspension and the second suspension are mixed, stirred for 10-15 hours, and then the third suspension is added, and stirring is continued for 20-28 hours; After stirring, the mixture was allowed to stand for 4-8 hours, the upper liquid was removed, and the mixture was freeze-dried to obtain the micro-nano hybrid filler.

[0010] Optionally, the concentration of the first suspension is 0.01-0.015 g / mL; the concentration of the second suspension is 0.01-0.015 g / mL; the concentration of the third suspension is 0.02-0.03 g / mL; The volume ratio of the first suspension, the second suspension and the third suspension is 1:1:(0.4-0.7).

[0011] Optionally, the mixing, kneading, sheeting, pressing and sintering of the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch comprises: The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed at 180-220° C. and 800-1200 rpm for 0.5-2 h to obtain a mixed powder; Compacting the mixed powder and pressing to obtain a green body; The green body is gradually heated to 1000-1150° C., sintered at 1000-1150° C. for 100-130 hours, and naturally cooled to room temperature.

[0012] Based on the same inventive concept, the present application also provides a pantograph slide plate reinforced with a micro-nano hybrid filler, which is prepared by the above-mentioned preparation method of a pantograph slide plate reinforced with a micro-nano hybrid filler.

[0013] The beneficial effects of the present invention are: The present invention prepares a micro-nano hybrid filler by electrostatic self-assembly of ethylenediamine-grafted graphene oxide, carboxyl-functionalized multi-walled carbon nanotubes and modified nano-silicon dioxide, so as to improve the flexural resistance, compressive strength, electrical conductivity, thermal conductivity and other properties of a pantograph slide plate. The micro-nano hybrid filler is a multi-scale ternary hybrid three-dimensional micro-nano structure formed by using flaky graphene oxide as a base surface, grafting carbon nanotubes on the graphene oxide base, and then modifying the surface of graphene oxide and carbon nanotubes with nano-silicon dioxide. Carbon nanotubes with a large aspect ratio can effectively transmit stress and change the stress direction, and flaky graphene oxide can disperse stress to other parts of the matrix, avoiding crack initiation and expansion caused by stress concentration. Silicon dioxide can increase the roughness of the surface of graphene oxide and carbon nanotubes, adjust the bonding interface structure with the matrix, enhance the interface bonding strength, and is conducive to the stress transmission between graphene oxide and carbon nanotubes and the matrix, thereby improving the mechanical properties of the pantograph slide plate such as flexural resistance and compressive strength.

[0014] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing embodiments of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0016] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0017] High-speed railways are the main arteries of the national economy and play a vital role in the economic development of our country. As a key component of the pantograph / contact network system of high-speed trains, the pantograph slide plate plays an important role in transferring energy from the contact network to the high-speed train. During service, the pantograph slide plate is not only in a critical working position, but also exposed to the natural environment for a long time, and the service environment is harsh. Therefore, the pantograph slide plate must have a series of excellent properties such as high mechanical strength and high conductivity. As the railway develops towards high speed and heavy load, higher requirements are also placed on the performance of the pantograph slide plate.

[0018] The current carbon-based composite pantograph slides generally have problems such as pores, cracks, and weak interface bonding, which makes their resistivity large and their mechanical properties low, and cannot fully meet the use requirements of high-speed train pantograph slides.

[0019] In order to solve the problems of the prior art, the present application provides a method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; The carbon nanotubes are modified by using an acid solution to obtain modified carbon nanotubes; The nano-silicon dioxide is modified by using a silane coupling agent to obtain modified silicon dioxide; The modified graphene oxide, modified nanotubes and modified silicon dioxide are mixed and subjected to electrostatic self-assembly to obtain a micro-nano hybrid filler; The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed, kneaded, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0020] The invention prepares a multi-scale micro-nano filler by electrostatic self-assembly of ethylenediamine-grafted graphene oxide, carboxyl-functionalized multi-walled carbon nanotubes and modified nano-silicon dioxide, so as to improve the bending resistance, compressive strength, electrical conductivity, thermal conductivity and other properties of the pantograph slide. The multi-scale micro-nano filler is a multi-scale ternary hybrid three-dimensional micro-nano structure formed by using flaky graphene oxide as the base surface, grafting carbon nanotubes on the graphene oxide base, and then modifying the graphene oxide and carbon nanotube surfaces with nano-silicon dioxide.

[0021] Carbon nanotubes with large aspect ratios can effectively transfer stress and change the direction of stress. Flake graphene oxide can disperse the transferred stress to other parts of the matrix, avoiding the initiation and expansion of cracks caused by stress concentration. The introduction of silicon dioxide increases the surface roughness of graphene oxide and carbon nanotubes, adjusts the interface structure with the matrix, and enhances the interface bonding strength, which is beneficial to the stress transfer between graphene oxide and carbon nanotubes and the matrix, thereby improving the mechanical properties of the pantograph slide, such as the flexural and compressive strength.

[0022] As an optional embodiment, the particle size of the nano-silicon dioxide is less than or equal to 20nm; the outer diameter of the carbon nanotube is 50-80nm, the length is 5-10μm, and the sheet diameter of the graphene oxide is>5μm. The use of large-diameter graphene oxide is more effective, which can increase the connection points between the carbon nanotube and the graphene oxide, and the transmission effect between the two is better. During electrostatic self-assembly, the carbon nanotube is first grafted on the surface of the flake graphene oxide, and then the small-diameter nano-silicon dioxide is dispersed and wrapped on the surface of the carbon nanotube and the graphene oxide, which improves the surface roughness.

[0023] As an optional embodiment, the method of modifying graphene oxide with ethylenediamine to obtain modified graphene oxide comprises: Adding graphene oxide to N,N-dimethylformamide for dispersion, and then adding N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine for further dispersion to obtain a graphene dispersion; The graphene dispersion is reacted at 55-65° C. for 6-10 hours. After the reaction is completed, the graphene is filtered, washed and dried to obtain modified graphene oxide, that is, ethylenediamine is grafted on the surface of the graphene oxide through modification.

[0024] The modified Hummers method can be used to chemically exfoliate natural graphite sheets to prepare graphene oxide. Specifically, after mixing flake graphite with concentrated sulfuric acid, potassium permanganate is added in small amounts and multiple times within 20 minutes, and the solution turns dark green. After continuing to stir in an ice-water bath for 15-20 minutes, stirring is continued at room temperature for 24 hours; deionized water is added under the conditions of an ice-water bath to achieve sheet exfoliation, and then hydrogen peroxide is slowly added dropwise to reduce potassium permanganate. After filtering, the solid is washed with 3wt% hydrochloric acid and deionized water, and freeze-dried to obtain graphene oxide.

[0025] As an optional implementation, the method of modifying the carbon nanotubes with an acid solution includes: The carbon nanotubes are added into a mixed solution of concentrated nitric acid and concentrated sulfuric acid, mixed and reacted at 40-60° C. for 3-5 hours, filtered and dried, that is, carboxyl groups are grafted onto the surface of the carbon nanotubes through acid treatment modification.

[0026] As an optional embodiment, the modification of nano-silicon dioxide using a silane coupling agent includes: Pre-soaking nano-silicon dioxide in anhydrous ethanol for 30-60 minutes, and then stirring and dispersing to obtain a silicon dioxide dispersion; The silica dispersion is stirred, and water is added thereto, and then a mixed solution of silane coupling agent and ethanol is added to the silica dispersion, and stirred at 60-80° C. for 6-10 hours, and then dried after centrifugal washing, so as to graft amino groups on the surface of nano-silica.

[0027] As an optional embodiment, the mass ratio of the asphalt coke, graphite powder, coal tar pitch and micro-nano hybrid rice filler is 65:(2-5):(23-27):(1-3), and more preferably, the mass ratio is 65:3:25:1.

[0028] As an optional embodiment, the modified graphene oxide, modified carbon nanotubes and modified silicon dioxide are mixed and electrostatically self-assembled to obtain a micro-nano hybrid filler, comprising: Adding the modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide into water and dispersing them for 1-1.5 hours respectively to obtain a first suspension, a second suspension, and a third suspension respectively; The first suspension and the second suspension are mixed, stirred for 10-15 hours, and then the third suspension is added, and stirring is continued for 20-28 hours; After stirring, the mixture was allowed to stand for 4-8 hours, the upper liquid was removed, and the mixture was freeze-dried to obtain the micro-nano hybrid filler.

[0029] As an optional embodiment, the concentration of the first suspension is 0.01-0.015 g / mL; the concentration of the second suspension is 0.01-0.015 g / mL; the concentration of the third suspension is 0.02-0.03 g / mL; The volume ratio of the first suspension, the second suspension and the third suspension is 1:1:(0.4-0.7). As an optional embodiment, the mixing, sheeting, pressing and sintering of the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch comprises: The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed at 180-220° C. and 800-1200 rpm for 0.5-2 h to obtain a mixed powder; The mixed powder is compacted and pressed to obtain a green body; when the green body is pressed, the pressing pressure is set to 18 MPa and the holding time is 2 hours. The compaction operation is: the mixed powder is compacted using a sheet rolling machine, the sheet is crushed and compacted again, and this process is repeated at least three times to obtain a composite powder.

[0030] The green body is gradually heated to 1000-1150°C, sintered at 1000-1150°C for 100-130h, and naturally cooled to room temperature. The operation of the gradient heating is as follows: the first stage: heating to 150-160°C at a rate of 40°C / h; the second stage: heating to 510-550°C at a rate of 10-15°C / h; the third stage: heating to 720-750°C at a rate of 35-50°C / h; the fourth stage: heating to 1000-1150°C at a rate of 70-80°C / h; Preferably, the particle size of the asphalt coke and graphite powder is less than 70 μm, and the particle size of the composite powder is less than 100 μm.

[0031] Asphalt undergoes thermal decomposition and polycondensation during the carbonization and sintering process, which can easily produce cracks and pore defects inside the pantograph slide. Crack pore structure defects and stress concentration are the main reasons affecting the mechanical properties of the pantograph slide. In the present invention, the surface modification and self-assembly of graphene oxide, carbon nanotubes, and nano-silicon dioxide are combined to avoid the agglomeration of nanomaterials and can be evenly dispersed in the slide. At the same time, the prepared multi-scale micro-nano filler can fill and adjust the cracks and pores inside the slide, reduce the porosity, promote the densification of the slide, and improve the flexural and compressive strength of the slide.

[0032] In composite materials, the main means of electrical and thermal conduction are electrons and phonons. Microcracks and pores inside the pantograph slide seriously hinder the transmission of electrons and phonons, affecting the electrical and thermal conductivity of the slide. In the present invention, the introduction of multi-scale micro-nano hybrid fillers reduces cracks and pores in the matrix, which is beneficial to the transmission of electrons and phonons in the matrix and improves the electrical and thermal conductivity of the pantograph slide. At the same time, part of the graphene oxide is reduced during the sintering process to generate reduced graphene oxide. The sheet structure of reduced graphene oxide / graphene oxide has a high surface area, which can increase the contact area with the matrix, which is beneficial to receiving electrons and phonons in the matrix. The collected electrons and phonons are transmitted through carbon nanotubes grafted on the surface of graphene oxide. The hollow tubular structure of carbon nanotubes can provide a more efficient transmission channel for the transport of electrons and phonons. In addition, the large aspect ratio of carbon nanotubes and the flaky structure of graphene oxide are more conducive to bridging between multi-scale micro-nano hybrid fillers, forming a three-dimensional conductive and thermal conductive network inside the skateboard, thereby further improving the conductive and thermal conductive properties of the skateboard.

[0033] The following describes the embodiments of the present invention through specific examples.

[0034] Embodiment 1: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: S1. Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; Add the prepared graphene oxide to N,N-dimethylformamide, and disperse it by ultrasonication for 1.5 h. Then, add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine, and continue to disperse it by ultrasonication for 0.5 h. The mixture was transferred to a 60°C oil bath for reaction for 8 hours. After the reaction was completed, the mixture was immediately filtered and then washed with N,N-dimethylformamide for 4 times. The mixture was dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0035] S2, modifying the carbon nanotubes with an acid solution to obtain modified carbon nanotubes; Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3, multi-walled carbon nanotubes (length of 10 μm) were slowly added into the mixture, the temperature was controlled at 40°C, ultrasonicated for 4 hours, filtered, and dried at 80°C for 24 hours to obtain modified carbon nanotubes.

[0036] S3, modifying nano silicon dioxide with a silane coupling agent to obtain modified silicon dioxide; Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and the silica powder was fully dispersed in the anhydrous ethanol using intermittent ultrasound (ultrasound for 10 minutes, rest for 5 minutes, a total of 1 hour); Deionized water was slowly added dropwise to the dispersed system after ultrasound while stirring was maintained to avoid local overconcentration, and a 1% NaOH solution was added dropwise to adjust the pH of the solution to 9.

[0037] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added to the reaction system, and stirred at 60° C. for 8 h. After the reaction, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0038] S4, mixing the modified graphene oxide, modified nanotubes and modified silicon dioxide, and performing electrostatic self-assembly to obtain a micro-nano hybrid filler; Specifically, the modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide were added to deionized water and ultrasonicated for 1 hour to obtain a first suspension, a second suspension, and a third suspension, respectively. The concentration of the first suspension was 0.01 g / mL; the concentration of the second suspension was 0.01 g / mL; the concentration of the third suspension was 0.025 g / mL; The first suspension and the second suspension were mixed, and magnetically stirred at room temperature for 12 hours, and then the third suspension was added, and magnetic stirring was continued for 24 hours. The volume ratio of the first suspension, the second suspension and the third suspension was 1:1:0.5.

[0039] After stirring, the mixture was allowed to stand for 6 h, the upper liquid layer was removed, and the lower solid layer was freeze-dried for 36 h to obtain the micro-nano hybrid filler.

[0040] S5, kneading the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch into sheets, pressing and sintering to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0041] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0042] The prepared micro-nano hybrid filler, raw material particles and coal tar pitch were put into a kneading device in proportion, mixed at 200°C and 1000 rpm for 1 hour to obtain a mixed powder. The mass ratio of pitch coke, graphite powder, coal tar pitch and micro-nano hybrid rice filler was 65:3:25:1.

[0043] The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0044] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0045] The green body is subjected to high-temperature sintering. The first stage: heating to 160°C at a rate of 40°C / h; the second stage: heating to 530°C at a rate of 12°C / h; the third stage: heating to 750°C at a rate of 40°C / h; the fourth stage: heating to 1050°C at a rate of 75°C / h; the fifth stage: sintering at 1050°C for 120h, and then naturally cooling to room temperature.

[0046] Embodiment 2: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: S1. Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; Add the prepared graphene oxide to N,N-dimethylformamide, and disperse it by ultrasonication for 1.5 h. Then, add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine, and continue to disperse it by ultrasonication for 0.5 h. The mixture was transferred to a 60°C oil bath and reacted for 8 hours. After the reaction was completed, the mixture was immediately filtered and then washed with N,N-dimethylformamide for 3 times. The mixture was dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0047] S2, modifying the carbon nanotubes with an acid solution to obtain modified carbon nanotubes; Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3, multi-walled carbon nanotubes (length 7 μm) were slowly added into the mixture, the temperature was controlled at 60°C, ultrasonicated for 4 hours, filtered, and dried at 80°C for 24 hours to obtain modified carbon nanotubes.

[0048] S3, modifying nano silicon dioxide with a silane coupling agent to obtain modified silicon dioxide; Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and the silica powder was fully dispersed in the anhydrous ethanol using intermittent ultrasound (ultrasound for 10 minutes, rest for 5 minutes, a total of 1 hour); Deionized water was slowly added dropwise to the dispersed system after ultrasound while stirring was maintained to avoid local overconcentration, and a 1% HCl solution was added dropwise to adjust the pH of the solution to 5.

[0049] γ-Aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added to the reaction system, and stirred at 80° C. for 6 hours. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 minutes, washed with anhydrous ethanol and deionized water for 3 times, and dried to obtain modified silica.

[0050] S4, mixing the modified graphene oxide, modified nanotubes and modified silicon dioxide, and performing electrostatic self-assembly to obtain a micro-nano hybrid filler; Specifically, the modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide were added to deionized water and ultrasonicated for 1 hour to obtain a first suspension, a second suspension, and a third suspension, respectively. The concentration of the first suspension was 0.012 g / mL; the concentration of the second suspension was 0.015 g / mL; the concentration of the third suspension was 0.028 g / mL; The first suspension and the second suspension were mixed, and magnetically stirred at room temperature for 12 hours, and then the third suspension was added, and magnetic stirring was continued for 24 hours. The volume ratio of the first suspension, the second suspension and the third suspension was 1:1:0.6.

[0051] After stirring, the mixture was allowed to stand for 6 h, the upper liquid was removed, and the mixture was freeze-dried for 36 h to obtain the micro-nano hybrid filler.

[0052] S5, kneading the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch into sheets, pressing and sintering to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0053] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0054] The prepared micro-nano hybrid filler, raw material particles, and coal tar pitch were put into a kneading device in proportion, and mixed at 200°C and 1000 rpm for 1 hour to obtain a mixed powder. The mass ratio of asphalt coke, graphite powder, coal tar pitch, and micro-nano hybrid rice filler was 65:3:23:2; The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0055] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0056] The green body is subjected to high-temperature sintering. The first stage: heating to 150°C at a rate of 40°C / h; the second stage: heating to 550°C at a rate of 15°C / h; the third stage: heating to 720°C at a rate of 50°C / h; the fourth stage: heating to 1000°C at a rate of 70°C / h; the fifth stage: sintering at 1050°C for 130h, and then naturally cooling to room temperature.

[0057] Embodiment 3: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: S1. Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; Add the prepared graphene oxide to N,N-dimethylformamide, and disperse it by ultrasonication for 1.5 h. Then, add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine, and continue to disperse it by ultrasonication for 0.5 h. The mixture was transferred to a 60°C oil bath for reaction for 8 hours. After the reaction was completed, the mixture was immediately filtered and then washed with N,N-dimethylformamide for 5 times. The mixture was dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0058] S2, modifying the carbon nanotubes with an acid solution to obtain modified carbon nanotubes; Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3, multi-walled carbon nanotubes (length 5 μm) were slowly added into the mixture, the temperature was controlled at 50°C, ultrasonicated for 4 hours, filtered, and dried at 80°C for 24 hours to obtain modified carbon nanotubes.

[0059] S3, modifying nano silicon dioxide with a silane coupling agent to obtain modified silicon dioxide; Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and the silica powder was fully dispersed in the anhydrous ethanol using intermittent ultrasound (ultrasound for 10 minutes, rest for 5 minutes, a total of 1 hour); Deionized water was slowly added dropwise to the dispersed system after ultrasound while maintaining stirring to avoid local overconcentration.

[0060] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added to the reaction system, and stirred at 70° C. for 7 hours. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 minutes, washed with anhydrous ethanol and deionized water for 3 times, and dried to obtain modified silica.

[0061] S4, mixing the modified graphene oxide, modified nanotubes and modified silicon dioxide, and performing electrostatic self-assembly to obtain a micro-nano hybrid filler; Specifically, the modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide were added to deionized water and ultrasonicated for 1 hour to obtain a first suspension, a second suspension, and a third suspension, respectively. The concentration of the first suspension was 0.015 g / mL; the concentration of the second suspension was 0.01 g / mL; the concentration of the third suspension was 0.02 g / mL; The first suspension and the second suspension were mixed, and magnetically stirred at room temperature for 12 hours, and then the third suspension was added, and magnetic stirring was continued for 12 hours. The volume ratio of the first suspension, the second suspension and the third suspension was 1:1:0.4.

[0062] After stirring, the mixture was allowed to stand for 6 h, the upper liquid was removed, and the mixture was freeze-dried for 36 h to obtain the micro-nano hybrid filler.

[0063] S5, kneading the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch into sheets, pressing and sintering to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0064] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0065] The prepared micro-nano hybrid filler, raw material particles, and coal tar pitch were put into a kneading device in proportion, and mixed at 200°C and 1000 rpm for 1 hour to obtain a mixed powder. The mass ratio of pitch coke, graphite powder, coal tar pitch, and micro-nano hybrid rice filler was 65:3:26:1; The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0066] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0067] The green body is subjected to high-temperature sintering. The first stage: heating to 155°C at a rate of 40°C / h; the second stage: heating to 510°C at a rate of 10°C / h; the third stage: heating to 730°C at a rate of 35°C / h; the fourth stage: heating to 1150°C at a rate of 80°C / h; the fifth stage: sintering at 1050°C for 120h, and then naturally cooling to room temperature.

[0068] Embodiment 4: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: S1. Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; Add the prepared graphene oxide to N,N-dimethylformamide, and disperse it by ultrasonication for 1.5 h. Then, add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine, and continue to disperse it by ultrasonication for 0.5 h. The mixture was transferred to a 60°C oil bath and reacted for 8 hours. After the reaction was completed, the mixture was immediately filtered and then washed with N,N-dimethylformamide for 3 times. The mixture was dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0069] S2, modifying the carbon nanotubes with an acid solution to obtain modified carbon nanotubes; Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3, multi-walled carbon nanotubes (length of 10 μm) were slowly added into the mixture, the temperature was controlled at 45°C, ultrasonicated for 4 hours, filtered, and dried at 80°C for 24 hours to obtain modified carbon nanotubes.

[0070] S3, modifying nano silicon dioxide with a silane coupling agent to obtain modified silicon dioxide; Specifically, the silicon dioxide powder is fully dispersed in anhydrous ethanol; Deionized water was slowly added dropwise to the silica dispersion while maintaining stirring to avoid local overconcentration.

[0071] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added to the reaction system, and stirred at 65° C. for 8 h. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0072] S4, mixing the modified graphene oxide, modified nanotubes and modified silicon dioxide, and performing electrostatic self-assembly to obtain a micro-nano hybrid filler; Specifically, the modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide were added to deionized water and ultrasonicated for 1 hour to obtain a first suspension, a second suspension, and a third suspension, respectively. The concentration of the first suspension was 0.015 g / mL; the concentration of the second suspension was 0.015 g / mL; the concentration of the third suspension was 0.02 g / mL; The first suspension and the second suspension were mixed, and magnetically stirred at room temperature for 12 hours, and then the third suspension was added, and magnetic stirring was continued for 24 hours. The volume ratio of the first suspension, the second suspension and the third suspension was 1:1:0.7.

[0073] After stirring, the mixture was allowed to stand for 6 h, the upper liquid layer was removed, and the lower solid layer was freeze-dried for 36 h to obtain the micro-nano hybrid filler.

[0074] S5, kneading the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch into sheets, pressing and sintering to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0075] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0076] The prepared micro-nano hybrid filler, raw material particles, and coal tar pitch were put into a kneading device in proportion, and mixed at 200°C and 1000 rpm for 1 hour to obtain a mixed powder. The mass ratio of asphalt coke, graphite powder, coal tar pitch, and micro-nano hybrid rice filler was 65:5:24:2; The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0077] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0078] The green body is subjected to high-temperature sintering. The first stage: heating to 155°C at a rate of 40°C / h; the second stage: heating to 520°C at a rate of 12°C / h; the third stage: heating to 740°C at a rate of 45°C / h; the fourth stage: heating to 1050°C at a rate of 70°C / h; the fifth stage: sintering at 1050°C for 120h, and then naturally cooling to room temperature.

[0079] Embodiment 5: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: S1. Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; Add the prepared graphene oxide to N,N-dimethylformamide, and disperse it by ultrasonication for 1.5 h. Then, add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine, and continue to disperse it by ultrasonication for 0.5 h. The mixture was transferred to a 60°C oil bath and reacted for 8 hours. After the reaction was completed, the mixture was immediately filtered and then washed with N,N-dimethylformamide for 3 times. The mixture was dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0080] S2, modifying the carbon nanotubes with an acid solution to obtain modified carbon nanotubes; Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3, multi-walled carbon nanotubes (length of 10 μm) were slowly added into the mixture, the temperature was controlled at 45°C, ultrasonicated for 4 hours, filtered, and dried at 80°C for 24 hours to obtain modified carbon nanotubes.

[0081] S3, modifying nano silicon dioxide with a silane coupling agent to obtain modified silicon dioxide; Specifically, the silicon dioxide powder is fully dispersed in anhydrous ethanol; Deionized water was slowly added dropwise to the silica dispersion while maintaining stirring to avoid local overconcentration.

[0082] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added to the reaction system, and stirred at 65° C. for 8 h. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 min, washed twice with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0083] S4, mixing the modified graphene oxide, modified nanotubes and modified silicon dioxide, and performing electrostatic self-assembly to obtain a micro-nano hybrid filler; Specifically, the modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide were added to deionized water and ultrasonicated for 1 hour to obtain a first suspension, a second suspension, and a third suspension, respectively. The concentration of the first suspension was 0.015 g / mL; the concentration of the second suspension was 0.015 g / mL; the concentration of the third suspension was 0.02 g / mL; The first suspension and the second suspension were mixed, and magnetically stirred at room temperature for 12 hours, and then the third suspension was added, and magnetic stirring was continued for 24 hours. The volume ratio of the first suspension, the second suspension and the third suspension was 1:1:0.7.

[0084] After stirring, the mixture was allowed to stand for 6 h, the upper liquid layer was removed, and the lower solid layer was freeze-dried for 36 h to obtain the micro-nano hybrid filler.

[0085] S5, kneading the micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch into sheets, pressing and sintering to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

[0086] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0087] The prepared micro-nano hybrid filler, raw material particles, and coal tar pitch were put into a kneading device in proportion, and mixed at 200°C and 1000 rpm for 1 hour to obtain a mixed powder. The mass ratio of asphalt coke, graphite powder, coal tar pitch, and micro-nano hybrid rice filler was 65:2:27:3; The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0088] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0089] The green body is subjected to high-temperature sintering. The first stage: heating to 150°C at a rate of 40°C / h; the second stage: heating to 540°C at a rate of 14°C / h; the third stage: heating to 745°C at a rate of 50°C / h; the fourth stage: heating to 1100°C at a rate of 80°C / h; the fifth stage: sintering at 1100°C for 120h, and then naturally cooling to room temperature.

[0090] Comparative Example 1: A method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers, comprising: S1. Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; Add the prepared graphene oxide to N,N-dimethylformamide, and disperse it by ultrasonication for 1.5 h. Then, add N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine, and continue to disperse it by ultrasonication for 0.5 h. The mixture was transferred to a 60°C oil bath for reaction for 8 hours. After the reaction was completed, the mixture was immediately filtered and then washed with N,N-dimethylformamide for 3-5 times. The modified graphene oxide was obtained after drying at 80°C for 12 hours.

[0091] S2, modifying nano silicon dioxide with a silane coupling agent to obtain modified silicon dioxide; Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and the silica powder was fully dispersed in the anhydrous ethanol using intermittent ultrasound (ultrasound for 10 minutes, rest for 5 minutes, a total of 1 hour); Deionized water was slowly added dropwise to the dispersed system after ultrasound while stirring was maintained to avoid local overconcentration, and a 1% NaOH solution was added dropwise to adjust the pH of the solution to 9.

[0092] Dissolve γ-aminopropyltriethoxysilane in a small amount of ethanol and slowly add it to the reaction system, and stir it at 60° C. for 8 hours. After the reaction is completed, centrifuge at 8000 rpm for 10 minutes, wash with anhydrous ethanol and deionized water 2-3 times, and dry to obtain modified silica.

[0093] S3, mixing the modified graphene oxide and modified silicon dioxide, and performing electrostatic self-assembly to obtain a filler; Specifically, modified graphene oxide and modified silicon dioxide were added to deionized water and ultrasonicated for 1 hour to obtain two suspensions. The concentration of the modified graphene oxide suspension was 0.01 g / mL and the concentration of the modified silicon dioxide suspension was 0.025 g / mL; The first suspension and the second suspension were mixed, and magnetically stirred at room temperature for 12 hours. After stirring, the mixture was allowed to stand for 6 hours, and the upper liquid was removed to leave the lower solution, which was freeze-dried for 36 hours to obtain the filler.

[0094] S4, kneading, sheeting, pressing and sintering the filler, pitch coke, graphite powder and coal tar pitch to obtain a reinforced pantograph slide plate. The mass ratio of the pitch coke, graphite powder, coal tar pitch and filler is 65:3:25:1.

[0095] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0096] The prepared filler, raw material particles and coal tar pitch were put into a kneading device in proportion, mixed at 200° C. and 1000 rpm for 1 hour to obtain a mixed powder.

[0097] The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0098] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0099] The green body is subjected to high-temperature calcination, with the temperature rising to 160°C at a rate of 40°C / h; the second stage: the temperature rises to 530°C at a rate of 12°C / h; the third stage: the temperature rises to 750°C at a rate of 40°C / h; the fourth stage: the temperature rises to 1050°C at a rate of 75°C / h; the fifth stage: sintering at 1050°C for 120h, and then naturally cooling to room temperature.

[0100] Comparative Example 2: A method for preparing a pantograph slide plate, comprising: S1. Add the graphene oxide, nanotubes and silicon dioxide into deionized water and ultrasonicate for 1 hour to obtain suspension A, suspension B and suspension C respectively. The concentration of suspension A is 0.01 g / mL; the concentration of suspension B is 0.01 g / mL; the concentration of suspension C is 0.025 g / mL; The suspension A and the suspension B were mixed, and magnetically stirred at room temperature for 12 hours, and then the suspension C was added, and magnetic stirring was continued for 24 hours. The volume ratio of the suspension A, the suspension B, and the suspension C was 1:1:0.5.

[0101] After stirring, the mixture was allowed to stand for 6 h, the upper liquid layer was removed, and the lower solid layer was freeze-dried for 36 h to obtain the filler.

[0102] S2, kneading the filler, asphalt coke, graphite powder and coal tar pitch into sheets, pressing and sintering to obtain a pantograph slide plate.

[0103] Specifically, the asphalt coke and graphite powder are crushed, ground and sieved respectively to obtain raw material particles with a particle size of less than 70 μm.

[0104] The prepared filler, raw material particles and coal tar pitch were put into a kneading device in proportion, mixed at 200°C and 1000 rpm for 1 hour to obtain a mixed powder. The mass ratio of pitch coke, graphite powder, coal tar pitch and filler was 65:3:25:1.

[0105] The prepared mixed powder is compacted using a sheet rolling machine, the flakes are crushed and compacted again, and this process is repeated three times to obtain a composite powder. Afterwards, the composite powder is sieved to ensure that the particle size of the composite powder is <100 μm.

[0106] The obtained composite powder was placed in a molding die and pressed using a hydraulic flat-plate vulcanizer, with the punching pressure set to 18 MPa and the holding time set to 2 h to form a green body.

[0107] The green body is subjected to high-temperature calcination, with the temperature rising to 160°C at a rate of 40°C / h; the second stage: the temperature rises to 530°C at a rate of 12°C / h; the third stage: the temperature rises to 750°C at a rate of 40°C / h; the fourth stage: the temperature rises to 1050°C at a rate of 75°C / h; the fifth stage: sintering at 1050°C for 120h, and then naturally cooling to room temperature.

[0108] Comparative Example 3: The preparation method of the pantograph slide plate of this comparative example is basically the same as that of Example 1, except that no filler is added, and only asphalt coke, graphite powder and coal tar are used as raw materials.

[0109] The performance tests were conducted on the pantograph slide samples prepared in Examples 1-3 and Comparative Examples 1-3. The compressive strength, flexural strength and impact toughness were tested using an electronic universal testing machine (the compressive strength sample size was 10mm×10mm×10mm, and the flexural and impact strength sample sizes were 32mm×8mm×4mm). The resistivity was tested using a high-precision resistivity tester (the sample size was 32mm×8mm×4mm), and the thermal conductivity was tested using a laser thermal conductivity meter (the sample size was 10mm×10mm×1.5mm). The tests are shown in Table 1.

[0110] Table 1

[0111] It can be seen from Table 1 that the pantograph slide plate prepared in the embodiment is generally superior to the comparative example in terms of compressive strength, flexural strength, impact toughness, resistivity and thermal conductivity. This is because the introduction of multi-scale micro-nano hybrid fillers significantly improves the comprehensive performance of the pantograph slide plate. In comparative example 1, silica-modified graphene oxide is used as a filler, and carbon nanotubes are not introduced. The filler cannot form a three-dimensional structure in the matrix, resulting in a decrease in the stress dispersion effect and electrical and thermal conductivity; the pantograph slide plate prepared in comparative example 2 has the lowest mechanical properties. This is because the added filler is not assembled and cannot play a synergistic enhancement role. Instead, it forms agglomerates inside the slide plate, resulting in stress concentration, thereby affecting the mechanical properties of the slide plate.

[0112] Based on the same inventive concept, the present application also provides a pantograph slide plate reinforced with a micro-nano hybrid filler, which is prepared by the preparation method of the pantograph slide plate reinforced with a micro-nano hybrid filler of the present application.

[0113] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers, characterized in that: include: Modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; The carbon nanotubes are modified by using an acid solution to obtain modified carbon nanotubes; The nano-silicon dioxide is modified by using a silane coupling agent to obtain modified silicon dioxide; The modified graphene oxide, modified nanotubes and modified silicon dioxide are mixed and subjected to electrostatic self-assembly to obtain a micro-nano hybrid filler; The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed, kneaded, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically reinforced pantograph slide plate.

2. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The particle size of the nano silicon dioxide is less than or equal to 20 nm; the outer diameter of the carbon nanotube is 50-80 nm, and the length is 5-10 μm.

3. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The method of modifying graphene oxide by using ethylenediamine to obtain modified graphene oxide comprises: Adding graphene oxide to N,N-dimethylformamide for dispersion, and then adding N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine for further dispersion to obtain a graphene dispersion; The graphene dispersion is reacted at 55-65° C. for 6-10 hours, and after the reaction is completed, the modified graphene oxide is obtained by filtering, washing and drying.

4. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The method of modifying the carbon nanotubes by using an acid solution comprises: The carbon nanotubes are added into a mixed solution of concentrated nitric acid and concentrated sulfuric acid, mixed and reacted at 40-60° C. for 3-5 hours, and then filtered and dried.

5. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The method of modifying nano silicon dioxide by using a silane coupling agent comprises: Pre-soaking nano-silicon dioxide in anhydrous ethanol for 30-60 minutes, and then stirring and dispersing to obtain a silicon dioxide dispersion; The silicon dioxide dispersion is stirred, and water is added dropwise thereto, and then a mixed solution of a silane coupling agent and ethanol is added dropwise to the silicon dioxide dispersion, and the mixture is stirred and reacted at 60-80° C. for 6-10 hours, and then dried after centrifugal washing.

6. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The mass ratio of the asphalt coke, graphite powder, coal tar pitch and micro-nano hybrid rice filler is 65:(2-5):(23-27):(1-3).

7. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The modified graphene oxide, modified carbon nanotubes and modified silicon dioxide are mixed and subjected to electrostatic self-assembly to obtain a micro-nano hybrid filler, comprising: The modified carbon nanotubes, modified graphene oxide, and modified silicon dioxide are respectively added into water and dispersed for 1-1.5 hours to obtain a first suspension, a second suspension, and a third suspension, respectively; The first suspension and the second suspension are mixed, stirred for 10-15 hours, and then the third suspension is added, and stirring is continued for 20-28 hours; After stirring, the mixture was allowed to stand for 4-8 hours, the upper liquid was removed, and the mixture was freeze-dried to obtain the micro-nano hybrid filler.

8. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 7, characterized in that: The concentration of the first suspension is 0.01-0.015 g / mL; the concentration of the second suspension is 0.01-0.015 g / mL; the concentration of the third suspension is 0.02-0.03 g / mL; the volume ratio of the first suspension, the second suspension and the third suspension is 1:1:(0.4-0.7).

9. The method for preparing a pantograph slide plate reinforced with micro-nano hybrid fillers according to claim 1, characterized in that: The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed, kneaded, sheeted, pressed and sintered, including: The micro-nano hybrid filler, asphalt coke, graphite powder and coal tar pitch are mixed at 180-220° C. and 800-1200 rpm for 0.5-2 h to obtain a mixed powder; Compacting the mixed powder and pressing to obtain a green body; The green body is gradually heated to 1000-1150° C., sintered at 1000-1150° C. for 100-130 hours, and naturally cooled to room temperature.

10. A pantograph slide plate reinforced with micro-nano hybrid fillers, characterized in that: The invention is prepared by the method for preparing a pantograph slide plate synergistically reinforced with micro-nano hybrid fillers as described in any one of claims 1 to 9.

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