Micro-nano hybrid filler synergistically reinforced pantograph slide rail and preparation method thereof

Abstract

This application relates to a micro / nano hybrid filler synergistically reinforcing pantograph slide plate and its preparation method, belonging to the field of composite materials. The method includes: modifying graphene oxide with ethylenediamine to obtain modified graphene oxide; modifying carbon nanotubes with an acid solution to obtain modified carbon nanotubes; modifying nano-silica with a silane coupling agent to obtain modified silica; mixing the modified graphene oxide, modified nanotubes, and modified silica, and performing electrostatic self-assembly to obtain a micro / nano hybrid filler; and mixing, rolling, pressing, and sintering the micro / nano hybrid filler, pitch coke, graphite powder, and coal tar pitch to obtain a micro / nano hybrid filler synergistically reinforcing pantograph slide plate. This invention prepares a micro / nano hybrid filler by electrostatic self-assembly of modified graphene oxide, carboxyl-functionalized carbon nanotubes, and modified nano-silica, thereby improving the flexural strength, compressive strength, electrical conductivity, and thermal conductivity of the pantograph slide plate.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and in particular to a micro / nano hybrid filler synergistically reinforced pantograph slide plate and its preparation method. Background Technology

[0002] Pantograph pantograph sliders have undergone several development stages, including metal sliders, pure carbon sliders, powder metallurgy sliders, metal-impregnated carbon sliders, and new composite material sliders. Carbon-based composite materials possess excellent properties such as low density, high strength, wear resistance, and high temperature resistance, showing broad application prospects in high-speed train pantograph sliders. However, carbon-based composite materials generally suffer from problems such as porosity, cracks, and weak interfacial bonding, affecting material performance and resulting in higher resistivity and lower mechanical properties, which cannot fully meet the usage requirements of high-speed train pantograph sliders. Therefore, there is an urgent need to develop carbon-based composite pantograph sliders with excellent mechanical and electrical properties to meet the service performance requirements of equipment in the rail transit field. Summary of the Invention

[0003] The purpose of this invention is to provide a micro / nano hybrid filler synergistically enhanced pantograph slider and its preparation method, in order to improve the above-mentioned problems. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0004] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0005] Graphene oxide was modified with ethylenediamine to obtain modified graphene oxide.

[0006] Carbon nanotubes were modified using an acid solution to obtain modified carbon nanotubes.

[0007] Nano-silica was modified using a silane coupling agent to obtain modified silica;

[0008] The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0009] The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

[0010] Optionally, the particle size of the nano-silica 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.

[0011] Optionally, the modification of graphene oxide with ethylenediamine to obtain modified graphene oxide includes:

[0012] Graphene oxide was added to N,N-dimethylformamide and dispersed. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and dispersed again to obtain a graphene dispersion.

[0013] The graphene dispersion was reacted at 55-65℃ for 6-10 hours. After the reaction was completed, the mixture was filtered, washed and dried to obtain modified graphene oxide.

[0014] Optionally, the modification of carbon nanotubes with an acid solution includes:

[0015] The carbon nanotubes were added to a mixture of concentrated nitric acid and concentrated sulfuric acid, and the mixture was reacted at 40-60°C for 3-5 hours before filtration and drying.

[0016] Optionally, the modification of nano-silica with a silane coupling agent includes:

[0017] Nano-silica was pre-soaked in anhydrous ethanol for 30-60 minutes, and then stirred and dispersed to obtain a silica dispersion.

[0018] The silica dispersion was stirred while water was added dropwise. Then, a mixed solution of silane coupling agent and ethanol was added dropwise to the silica dispersion, and the mixture was stirred at 60-80°C for 6-10 hours. After centrifugation and washing, the mixture was dried.

[0019] 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).

[0020] Optionally, the modified graphene oxide, modified carbon nanotubes, and modified silica are mixed and electrostatically self-assembled to obtain a micro / nano hybrid filler, comprising:

[0021] The modified carbon nanotubes, modified graphene oxide, and modified silica were respectively added to water and dispersed for 1-1.5 hours to obtain the first suspension, the second suspension, and the third suspension, respectively.

[0022] Mix the first suspension and the second suspension and stir for 10-15 hours, then add the third suspension and continue stirring for 20-28 hours;

[0023] After stirring, let stand for 4-8 hours, remove the upper liquid, and freeze-dry to obtain micro-nano hybrid filler.

[0024] 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; and the concentration of the third suspension is 0.02-0.03 g / mL.

[0025] The volume ratio of the first suspension, the second suspension, and the third suspension is 1:1:(0.4-0.7).

[0026] Optionally, the step of mixing, rolling, pressing, and sintering the micro / nano hybrid filler, pitch coke, graphite powder, and coal tar pitch includes:

[0027] The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed at 180-220℃ and 800-1200 rpm for 0.5-2 hours to obtain a mixed powder.

[0028] The mixed powder is compacted and pressed to obtain a green body;

[0029] The green body is gradually heated to 1000-1150℃ and sintered at 1000-1150℃ for 100-130 hours, then naturally cooled to room temperature.

[0030] Based on the same inventive concept, this application also provides a pantograph slider with micro-nano hybrid filler synergistic enhancement, which is prepared by the above-mentioned preparation method of pantograph slider with micro-nano hybrid filler synergistic enhancement.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention utilizes ethylenediamine-grafted graphene oxide, carboxyl-functionalized multi-walled carbon nanotubes, and modified nano-silica to prepare a micro / nano hybrid filler via electrostatic self-assembly, thereby improving the flexural and compressive strength, electrical conductivity, and thermal conductivity of pantograph contactors. This micro / nano hybrid filler uses sheet-like graphene oxide as the base surface, grafts carbon nanotubes onto the graphene substrate, and then modifies the surfaces of both the graphene oxide and carbon nanotubes with nano-silica, forming a multi-scale ternary hybrid three-dimensional micro / nano structure. The high aspect ratio of the carbon nanotubes effectively transmits stress and alters its direction, while the sheet-like graphene oxide disperses stress to other parts of the matrix, preventing stress concentration-induced crack initiation and propagation. Silica increases the surface roughness of the graphene oxide and carbon nanotubes, modulates the interface structure with the matrix, enhances the interfacial bonding strength, and facilitates stress transmission between the graphene oxide / carbon nanotubes and the matrix, thus improving the mechanical properties of the pantograph contactor, such as flexural and compressive strength.

[0033] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0035] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0036] High-speed railways are the lifeblood of the national economy, playing a vital role in my country's economic development. The pantograph contactor, as a key component of the pantograph / overhead contact system of high-speed trains, plays a crucial role in transferring energy from the overhead contact system to the train. During service, the pantograph contactor not only operates in a critical position but is also exposed to harsh natural environments for extended periods. Therefore, it must possess a range of superior properties, including high mechanical strength and high conductivity. With the development of railways towards high speed and heavy loads, even higher performance requirements are being placed on the pantograph contactor.

[0037] Current carbon-based composite pantograph contactors generally suffer from problems such as porosity, cracks, and weak interfacial bonding, resulting in high resistivity and low mechanical properties, which cannot fully meet the requirements for use in high-speed train pantograph contactors.

[0038] To address the problems of existing technologies, this application provides a method for preparing a pantograph slider that is synergistically enhanced by micro / nano hybrid fillers, comprising:

[0039] Graphene oxide was modified with ethylenediamine to obtain modified graphene oxide.

[0040] Carbon nanotubes were modified using an acid solution to obtain modified carbon nanotubes.

[0041] Nano-silica was modified using a silane coupling agent to obtain modified silica;

[0042] The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0043] The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

[0044] This invention utilizes ethylenediamine-grafted graphene oxide, carboxyl-functionalized multi-walled carbon nanotubes, and modified nano-silica to prepare multi-scale micro / nano fillers via electrostatic self-assembly, aiming to improve the flexural strength, compressive strength, electrical conductivity, and thermal conductivity of pantograph sliders. These multi-scale micro / nano fillers are based on sheet-like graphene oxide, with carbon nanotubes grafted onto the graphene substrate, and then the surfaces of both the graphene oxide and carbon nanotubes are modified with nano-silica, forming a multi-scale ternary hybrid three-dimensional micro / nano structure.

[0045] Carbon nanotubes with a high aspect ratio can effectively transfer stress and change its direction. Sheet-like graphene oxide can disperse the transferred stress to other parts of the matrix, avoiding crack initiation and propagation caused by stress concentration. The introduction of silica increases the surface roughness of graphene oxide and carbon nanotubes, adjusts the interface structure with the matrix, enhances the interfacial bonding strength, and facilitates stress transfer between graphene oxide and carbon nanotubes and the matrix, thereby improving the mechanical properties of the pantograph sliding plate, such as its flexural and compressive strength.

[0046] As an optional implementation, the nano-silica has a particle size of less than or equal to 20 nm; the carbon nanotubes have an outer diameter of 50-80 nm and a length of 5-10 μm; and the graphene oxide has a sheet diameter > 5 μm. Using large-diameter graphene oxide is more effective, as it increases the number of connection sites between the carbon nanotubes and graphene oxide, resulting in better transfer between them. During electrostatic self-assembly, the carbon nanotubes are first grafted onto the surface of the sheet-like graphene oxide, and then small-diameter nano-silica is dispersed and coated on the surfaces of the carbon nanotubes and graphene oxide, improving surface roughness.

[0047] As an optional implementation, the modification of graphene oxide with ethylenediamine to obtain modified graphene oxide includes:

[0048] Graphene oxide was added to N,N-dimethylformamide and dispersed. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and dispersed again to obtain a graphene dispersion.

[0049] The graphene dispersion was reacted at 55-65℃ for 6-10 hours. After the reaction was completed, it was filtered, washed and dried to obtain modified graphene oxide, which is obtained by grafting ethylenediamine onto the surface of graphene oxide.

[0050] Graphene oxide can be prepared by chemically exfoliating natural graphite flakes using a modified Hummers method. Specifically, flake graphite is mixed with concentrated sulfuric acid, and potassium permanganate is added in small amounts several times over 20 minutes. The solution turns dark green. The mixture is stirred in an ice-water bath for 15-20 minutes, and then stirred at room temperature for 24 hours. Deionized water is added under ice-water bath conditions to achieve flake exfoliation. Then, hydrogen peroxide is slowly added dropwise to reduce potassium permanganate. After filtration, the solid is washed with 3wt% hydrochloric acid and deionized water, and then freeze-dried to obtain graphene oxide.

[0051] As an optional implementation, the modification of carbon nanotubes with an acid solution includes:

[0052] The carbon nanotubes are added to a mixture of concentrated nitric acid and concentrated sulfuric acid, and after mixing and reacting at 40-60°C for 3-5 hours, they are filtered and dried, which is to modify the carbon nanotubes by grafting carboxyl groups onto the surface through acid treatment.

[0053] As an optional implementation, the modification of nano-silica with a silane coupling agent includes:

[0054] Nano-silica was pre-soaked in anhydrous ethanol for 30-60 minutes, and then stirred and dispersed to obtain a silica dispersion.

[0055] The silica dispersion is stirred while water is added dropwise. Then, a mixed solution of silane coupling agent and ethanol is added dropwise to the silica dispersion and stirred at 60-80°C for 6-10 hours. After centrifugation, washing, and drying, amino groups are grafted onto the surface of nano-silica.

[0056] As an optional implementation, 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.

[0057] As an optional implementation, the modified graphene oxide, modified carbon nanotubes, and modified silica are mixed and electrostatically self-assembled to obtain a micro / nano hybrid filler, comprising:

[0058] The modified carbon nanotubes, modified graphene oxide, and modified silica were respectively added to water and dispersed for 1-1.5 hours to obtain the first suspension, the second suspension, and the third suspension, respectively.

[0059] Mix the first suspension and the second suspension and stir for 10-15 hours, then add the third suspension and continue stirring for 20-28 hours;

[0060] After stirring, let stand for 4-8 hours, remove the upper liquid, and freeze-dry to obtain micro-nano hybrid filler.

[0061] As an optional implementation, 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; and the concentration of the third suspension is 0.02-0.03 g / mL.

[0062] The volume ratio of the first suspension, the second suspension, and the third suspension is 1:1:(0.4-0.7). As an optional implementation, the process of mixing, rolling, pressing, and sintering the micro / nano hybrid filler, pitch coke, graphite powder, and coal tar pitch includes:

[0063] The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed at 180-220℃ and 800-1200 rpm for 0.5-2 hours to obtain a mixed powder.

[0064] The mixed powder is compacted and pressed to obtain a green body; the pressing pressure is set to 18 MPa and the holding time is 2 hours. The compaction operation is as follows: the mixed powder is compacted using a rolling mill, the sheet is broken and compacted again, and this process is repeated at least three times to obtain composite powder.

[0065] The green embryo is gradually heated to 1000-1150℃ and sintered at 1000-1150℃ for 100-130 hours, then naturally cooled to room temperature. The gradient heating operation is as follows: First stage: heating to 150-160℃ at a rate of 40℃ / h; Second stage: heating to 510-550℃ at a rate of 10-15℃ / h; Third stage: heating to 720℃-750℃ at a rate of 35-50℃ / h; Fourth stage: heating to 1000-1150℃ at a rate of 70-80℃ / h.

[0066] Preferably, the particle size of the pitch coke and graphite powder is <70μm, and the particle size of the composite powder is <100μm.

[0067] During the carbonization and sintering process, asphalt undergoes pyrolysis and polycondensation, which easily leads to cracks and porosity defects within the pantograph sliding plate. These cracks, porosity defects, and stress concentration are the main reasons affecting the mechanical properties of the pantograph sliding plate. In this invention, the surface modification and self-assembly of graphene oxide, carbon nanotubes, and nano-silica avoid the aggregation of nanomaterials, allowing them to be uniformly dispersed within the sliding plate. Simultaneously, the prepared multi-scale micro / nano fillers can fill and regulate the cracks and pores within the sliding plate, reducing porosity, promoting densification, and improving the plate's flexural and compressive strength.

[0068] In composite materials, electrical and thermal conductivity primarily relies on electrons and phonons. Microcracks and pores within the pantograph slider severely hinder electron and phonon transport, affecting its electrical and thermal conductivity. In this invention, the introduction of multi-scale micro / nano hybrid fillers reduces cracks and pores in the matrix, facilitating electron and phonon transport and improving the pantograph slider's electrical and thermal conductivity. Simultaneously, some graphene oxide is reduced to reduced graphene oxide during sintering. The sheet-like structure of reduced graphene oxide / graphene oxide has a high surface area, increasing the contact area with the matrix and facilitating the reception of electrons and phonons. These collected electrons and phonons are then transported through carbon nanotubes grafted onto the graphene oxide surface. The hollow tubular structure of the carbon nanotubes provides a more efficient transport channel for electrons and phonons. Furthermore, the large aspect ratio of carbon nanotubes and the sheet-like structure of graphene oxide are more conducive to bridging between multi-scale micro-nano hybrid fillers, forming a three-dimensional conductive and thermally conductive network inside the slide plate, thereby further improving the conductive and thermally conductive performance of the slide plate.

[0069] The following specific examples illustrate the implementation of the present invention.

[0070] Example 1:

[0071] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0072] S1. Graphene oxide is modified with ethylenediamine to obtain modified graphene oxide;

[0073] The prepared graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed for 1.5 h. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and ultrasonically dispersed for another 0.5 h.

[0074] The mixture was transferred to an oil bath at 60°C and reacted for 8 hours. After the reaction was completed, it was immediately filtered. The filter was then washed four times with N,N-dimethylformamide and dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0075] S2. Carbon nanotubes are modified with acid solution to obtain modified carbon nanotubes;

[0076] Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3. Multi-walled carbon nanotubes (10 μm in length) were slowly added to the mixture. The temperature was controlled at 40 °C. After sonication for 4 hours, the mixture was filtered and dried at 80 °C for 24 hours to obtain modified carbon nanotubes.

[0077] S3. Modify nano-silica with a silane coupling agent to obtain modified silica;

[0078] Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and then the silica powder was fully dispersed in anhydrous ethanol using intermittent ultrasound (10 minutes of ultrasound, 5 minutes of rest, for a total of 1 hour).

[0079] Slowly add deionized water dropwise to the ultrasonically dispersed system while stirring to avoid local over-concentration. Adjust the pH of the solution to 9 by adding a 1% NaOH solution.

[0080] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added dropwise to the reaction system, which was stirred at 60 °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.

[0081] S4. The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0082] Specifically, modified carbon nanotubes, modified graphene oxide, and modified silica were added to deionized water and sonicated 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; and the concentration of the third suspension was 0.025 g / mL.

[0083] The first and second suspensions were mixed and magnetically stirred at room temperature for 12 hours. Then, the third suspension was added, and magnetic stirring was continued for another 24 hours. The volume ratio of the first, second, and third suspensions was 1:1:0.5.

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

[0085] S5. The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

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

[0087] The prepared micro / nano hybrid filler, raw material particles, and coal tar pitch were added to a mixing device in a certain proportion and mixed at 200℃ 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 filler was 65:3:25:1.

[0088] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0089] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0090] The green body was subjected to high-temperature firing in the following stages: first stage: heating to 160℃ at a rate of 40℃ / h; second stage: heating to 530℃ at a rate of 12℃ / h; third stage: heating to 750℃ at a rate of 40℃ / h; fourth stage: heating to 1050℃ at a rate of 75℃ / h; fifth stage: sintering at 1050℃ for 120h, and then naturally cooling to room temperature.

[0091] Example 2:

[0092] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0093] S1. Graphene oxide is modified with ethylenediamine to obtain modified graphene oxide;

[0094] The prepared graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed for 1.5 h. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and ultrasonically dispersed for another 0.5 h.

[0095] The mixture was transferred to an oil bath at 60°C and reacted for 8 hours. After the reaction was completed, it was immediately filtered. The filter was then washed three times with N,N-dimethylformamide and dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0096] S2. Carbon nanotubes are modified with acid solution to obtain modified carbon nanotubes;

[0097] Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3. Multi-walled carbon nanotubes (7 μm in length) were slowly added to the mixture. The temperature was controlled at 60 °C. After sonication for 4 hours, the mixture was filtered and dried at 80 °C for 24 hours to obtain modified carbon nanotubes.

[0098] S3. Modify nano-silica with a silane coupling agent to obtain modified silica;

[0099] Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and then the silica powder was fully dispersed in anhydrous ethanol using intermittent ultrasound (10 minutes of ultrasound, 5 minutes of rest, for a total of 1 hour).

[0100] Slowly add deionized water dropwise to the ultrasonically dispersed system while stirring to avoid local over-concentration. Adjust the pH of the solution to 5 by adding a 1% HCl solution.

[0101] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added dropwise to the reaction system, which was stirred at 80 °C for 6 h. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0102] S4. The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0103] Specifically, modified carbon nanotubes, modified graphene oxide, and modified silica were added to deionized water and sonicated 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; and the concentration of the third suspension was 0.028 g / mL.

[0104] The first and second suspensions were mixed and magnetically stirred at room temperature for 12 hours. Then, the third suspension was added, and magnetic stirring was continued for another 24 hours. The volume ratio of the first, second, and third suspensions was 1:1:0.6.

[0105] After stirring, the mixture was allowed to stand for 6 hours, the supernatant was removed, and the mixture was freeze-dried for 36 hours to obtain the micro-nano hybrid filler.

[0106] S5. The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

[0107] Specifically, the pitch coke and graphite powder are crushed, ground, and sieved to obtain raw material particles with a particle size of <70μm.

[0108] The prepared micro / nano hybrid filler, raw material particles, and coal tar pitch were added to a mixing device in a certain proportion and mixed at 200℃ 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 filler was 65:3:23:2.

[0109] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0110] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0111] The green body was subjected to high-temperature firing in the following stages: first stage: heating to 150℃ at a rate of 40℃ / h; second stage: heating to 550℃ at a rate of 15℃ / h; third stage: heating to 720℃ at a rate of 50℃ / h; fourth stage: heating to 1000℃ at a rate of 70℃ / h; fifth stage: sintering at 1050℃ for 130h, followed by natural cooling to room temperature.

[0112] Example 3:

[0113] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0114] S1. Graphene oxide is modified with ethylenediamine to obtain modified graphene oxide;

[0115] The prepared graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed for 1.5 h. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and ultrasonically dispersed for another 0.5 h.

[0116] The mixture was transferred to an oil bath at 60°C and reacted for 8 hours. After the reaction was completed, it was immediately filtered. The filter was then washed five times with N,N-dimethylformamide and dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0117] S2. Carbon nanotubes are modified with acid solution to obtain modified carbon nanotubes;

[0118] Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3. Multi-walled carbon nanotubes (5 μm in length) were slowly added to the mixture. The temperature was controlled at 50 °C. After sonication for 4 hours, the mixture was filtered and dried at 80 °C for 24 hours to obtain modified carbon nanotubes.

[0119] S3. Modify nano-silica with a silane coupling agent to obtain modified silica;

[0120] Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and then the silica powder was fully dispersed in anhydrous ethanol using intermittent ultrasound (10 minutes of ultrasound, 5 minutes of rest, for a total of 1 hour).

[0121] Slowly add deionized water dropwise to the ultrasonically dispersed system while stirring to avoid local over-concentration.

[0122] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added dropwise to the reaction system, which was stirred at 70°C for 7 h. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 min, washed three times with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0123] S4. The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0124] Specifically, modified carbon nanotubes, modified graphene oxide, and modified silica were added to deionized water and sonicated 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; and the concentration of the third suspension was 0.02 g / mL.

[0125] The first and second suspensions were mixed and magnetically stirred at room temperature for 12 hours. Then, the third suspension was added, and magnetic stirring was continued for another 12 hours. The volume ratio of the first, second, and third suspensions was 1:1:0.4.

[0126] After stirring, the mixture was allowed to stand for 6 hours, the supernatant was removed, and the mixture was freeze-dried for 36 hours to obtain the micro-nano hybrid filler.

[0127] S5. The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

[0128] Specifically, the pitch coke and graphite powder are crushed, ground, and sieved to obtain raw material particles with a particle size of <70μm.

[0129] The prepared micro / nano hybrid filler, raw material particles, and coal tar pitch were added to a mixing device in a certain proportion and mixed at 200℃ 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 filler was 65:3:26:1.

[0130] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0131] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0132] The green body was subjected to high-temperature firing in the following stages: first stage: heating to 155℃ at a rate of 40℃ / h; second stage: heating to 510℃ at a rate of 10℃ / h; third stage: heating to 730℃ at a rate of 35℃ / h; fourth stage: heating to 1150℃ at a rate of 80℃ / h; fifth stage: sintering at 1050℃ for 120h, and then naturally cooling to room temperature.

[0133] Example 4:

[0134] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0135] S1. Graphene oxide is modified with ethylenediamine to obtain modified graphene oxide;

[0136] The prepared graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed for 1.5 h. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and ultrasonically dispersed for another 0.5 h.

[0137] The mixture was transferred to an oil bath at 60°C and reacted for 8 hours. After the reaction was completed, it was immediately filtered. The filter was then washed three times with N,N-dimethylformamide and dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0138] S2. Carbon nanotubes are modified with acid solution to obtain modified carbon nanotubes;

[0139] Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3. Multi-walled carbon nanotubes (10 μm in length) were slowly added to the mixture. The temperature was controlled at 45 °C. After sonication for 4 hours, the mixture was filtered and dried at 80 °C for 24 hours to obtain modified carbon nanotubes.

[0140] S3. Modify nano-silica with a silane coupling agent to obtain modified silica;

[0141] Specifically, the silica powder is fully dispersed in anhydrous ethanol;

[0142] Slowly add deionized water dropwise to the silica dispersion while stirring to avoid localized over-concentration.

[0143] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added dropwise to the reaction system, which was stirred at 65°C for 8 hours. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 minutes, washed twice with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0144] S4. The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0145] Specifically, modified carbon nanotubes, modified graphene oxide, and modified silica were added to deionized water and sonicated 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; and the concentration of the third suspension was 0.02 g / mL.

[0146] The first and second suspensions were mixed and magnetically stirred at room temperature for 12 hours. Then, the third suspension was added, and magnetic stirring was continued for another 24 hours. The volume ratio of the first, second, and third suspensions was 1:1:0.7.

[0147] After stirring, the mixture was allowed to stand for 6 hours, the upper liquid was removed, and the lower solid was freeze-dried for 36 hours to obtain the micro-nano hybrid filler.

[0148] S5. The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

[0149] Specifically, the pitch coke and graphite powder are crushed, ground, and sieved to obtain raw material particles with a particle size of <70μm.

[0150] The prepared micro / nano hybrid filler, raw material particles, and coal tar pitch were added to a mixing device in a certain proportion and mixed at 200℃ 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 filler was 65:5:24:2.

[0151] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0152] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0153] The green body was subjected to high-temperature firing in the following stages: first stage: heating to 155℃ at a rate of 40℃ / h; second stage: heating to 520℃ at a rate of 12℃ / h; third stage: heating to 740℃ at a rate of 45℃ / h; fourth stage: heating to 1050℃ at a rate of 70℃ / h; fifth stage: sintering at 1050℃ for 120h, and then naturally cooling to room temperature.

[0154] Example 5:

[0155] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0156] S1. Graphene oxide is modified with ethylenediamine to obtain modified graphene oxide;

[0157] The prepared graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed for 1.5 h. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and ultrasonically dispersed for another 0.5 h.

[0158] The mixture was transferred to an oil bath at 60°C and reacted for 8 hours. After the reaction was completed, it was immediately filtered. The filter was then washed three times with N,N-dimethylformamide and dried at 80°C for 12 hours to obtain ethylenediamine-grafted graphene oxide.

[0159] S2. Carbon nanotubes are modified with acid solution to obtain modified carbon nanotubes;

[0160] Concentrated nitric acid and concentrated sulfuric acid were mixed in a ratio of 1:3. Multi-walled carbon nanotubes (10 μm in length) were slowly added to the mixture. The temperature was controlled at 45 °C. After sonication for 4 hours, the mixture was filtered and dried at 80 °C for 24 hours to obtain modified carbon nanotubes.

[0161] S3. Modify nano-silica with a silane coupling agent to obtain modified silica;

[0162] Specifically, the silica powder is fully dispersed in anhydrous ethanol;

[0163] Slowly add deionized water dropwise to the silica dispersion while stirring to avoid localized over-concentration.

[0164] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added dropwise to the reaction system, which was stirred at 65°C for 8 hours. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 minutes, washed twice with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0165] S4. The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers.

[0166] Specifically, modified carbon nanotubes, modified graphene oxide, and modified silica were added to deionized water and sonicated 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; and the concentration of the third suspension was 0.02 g / mL.

[0167] The first and second suspensions were mixed and magnetically stirred at room temperature for 12 hours. Then, the third suspension was added, and magnetic stirring was continued for another 24 hours. The volume ratio of the first, second, and third suspensions was 1:1:0.7.

[0168] After stirring, the mixture was allowed to stand for 6 hours, the upper liquid was removed, and the lower solid was freeze-dried for 36 hours to obtain the micro-nano hybrid filler.

[0169] S5. The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

[0170] Specifically, the pitch coke and graphite powder are crushed, ground, and sieved to obtain raw material particles with a particle size of <70μm.

[0171] The prepared micro / nano hybrid filler, raw material particles, and coal tar pitch were added to a mixing device in a certain proportion and mixed at 200℃ 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 filler was 65:2:27:3.

[0172] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0173] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0174] The green body was subjected to high-temperature firing in the following stages: first stage: heating to 150℃ at a rate of 40℃ / h; second stage: heating to 540℃ at a rate of 14℃ / h; third stage: heating to 745℃ at a rate of 50℃ / h; fourth stage: heating to 1100℃ at a rate of 80℃ / h; fifth stage: sintering at 1100℃ for 120h, and then naturally cooling to room temperature.

[0175] Comparative Example 1:

[0176] A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers includes:

[0177] S1. Graphene oxide is modified with ethylenediamine to obtain modified graphene oxide;

[0178] The prepared graphene oxide was added to N,N-dimethylformamide and ultrasonically dispersed for 1.5 h. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and ultrasonically dispersed for another 0.5 h.

[0179] The mixture was transferred to an oil bath at 60°C and reacted for 8 hours. After the reaction was completed, it was immediately filtered. The filter was then washed 3-5 times with N,N-dimethylformamide and dried at 80°C for 12 hours to obtain modified graphene oxide.

[0180] S2. Modify nano-silica with a silane coupling agent to obtain modified silica;

[0181] Specifically, the nano-silica powder was pre-soaked in anhydrous ethanol for 40 minutes, and then the silica powder was fully dispersed in anhydrous ethanol using intermittent ultrasound (10 minutes of ultrasound, 5 minutes of rest, for a total of 1 hour).

[0182] Slowly add deionized water dropwise to the ultrasonically dispersed system while stirring to avoid local over-concentration. Adjust the pH of the solution to 9 by adding a 1% NaOH solution.

[0183] γ-aminopropyltriethoxysilane was dissolved in a small amount of ethanol and slowly added dropwise to the reaction system, which was stirred at 60°C for 8 hours. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 minutes, washed 2-3 times with anhydrous ethanol and deionized water, and dried to obtain modified silica.

[0184] S3. The modified graphene oxide and modified silicon dioxide are mixed and electrostatically self-assembled to obtain the filler.

[0185] Specifically, modified graphene oxide and modified silica were added to deionized water and sonicated 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 silica suspension was 0.025 g / mL.

[0186] The first and second suspensions were mixed and magnetically stirred at room temperature for 12 hours. After stirring, the mixture was allowed to stand for 6 hours, the upper liquid was removed, leaving the remaining solution, which was then freeze-dried for 36 hours to obtain the filler.

[0187] S4. The filler, pitch coke, graphite powder, and coal tar pitch are mixed, kneaded, rolled, pressed, and sintered to obtain a reinforced pantograph sliding plate. The mass ratio of pitch coke, graphite powder, coal tar pitch, and filler is 65:3:25:1.

[0188] Specifically, the pitch coke and graphite powder are crushed, ground, and sieved to obtain raw material particles with a particle size of <70μm.

[0189] The prepared filler, raw material particles, and coal tar pitch were added into a mixing device in proportion and mixed at 200℃ and 1000rpm for 1 hour to obtain a mixed powder.

[0190] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0191] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0192] The green body was subjected to high-temperature firing, with the temperature increased to 160℃ at a rate of 40℃ / h; the second stage: the temperature was increased to 530℃ at a rate of 12℃ / h; the third stage: the temperature was increased to 750℃ at a rate of 40℃ / h; the fourth stage: the temperature was increased to 1050℃ at a rate of 75℃ / h; the fifth stage: sintering at 1050℃ for 120h, and then naturally cooled to room temperature.

[0193] Comparative Example 2:

[0194] A method for manufacturing a pantograph slider, comprising:

[0195] S1. The graphene oxide, nanotubes, and silicon dioxide were added to deionized water and sonicated for 1 hour to obtain suspensions A, B, and C, respectively. The concentration of suspension A was 0.01 g / mL; the concentration of suspension B was 0.01 g / mL; and the concentration of suspension C was 0.025 g / mL.

[0196] Suspension A and suspension B were mixed and magnetically stirred at room temperature for 12 hours. Then suspension C was added, and magnetic stirring was continued for another 24 hours. The volume ratio of suspension A, suspension B, and suspension C was 1:1:0.5.

[0197] After stirring, the mixture was allowed to stand for 6 hours. The upper liquid layer was removed, and the lower solid layer was freeze-dried for 36 hours to obtain the filler.

[0198] S2. The filler, pitch coke, graphite powder and coal tar pitch are mixed, kneaded, rolled, pressed and sintered to obtain the pantograph slide plate.

[0199] Specifically, the pitch coke and graphite powder are crushed, ground, and sieved to obtain raw material particles with a particle size of <70μm.

[0200] The prepared filler, raw material particles, and coal tar pitch were added to a mixing device in a certain proportion and mixed at 200℃ 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.

[0201] The prepared mixed powder was compacted using a sheet rolling mill, the sheet was broken up and compacted again, and this process was repeated three times to obtain composite powder. The composite powder was then sieved to ensure that the particle size was <100μm.

[0202] The obtained composite powder was placed into a molding die and pressed into shape using a hydraulic flat vulcanizing machine. The pressing pressure was set to 18 MPa and the holding time was 2 hours to form a green compact.

[0203] The green body was subjected to high-temperature firing, with the temperature increased to 160℃ at a rate of 40℃ / h; the second stage: the temperature was increased to 530℃ at a rate of 12℃ / h; the third stage: the temperature was increased to 750℃ at a rate of 40℃ / h; the fourth stage: the temperature was increased to 1050℃ at a rate of 75℃ / h; the fifth stage: sintering at 1050℃ for 120h, and then naturally cooled to room temperature.

[0204] Comparative Example 3:

[0205] The preparation method of the pantograph sliding plate in this comparative example is basically the same as that in Example 1, except that no filler is added and only pitch coke, graphite powder and coal tar pitch are used as raw materials.

[0206] The pantograph sliding plate samples prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The compressive strength, flexural strength, and impact toughness were tested using an electronic universal testing machine (compressive strength sample size: 10mm × 10mm × 10mm; flexural and impact strength sample sizes: 32mm × 8mm × 4mm). The resistivity was tested using a high-precision resistivity meter (sample size: 32mm × 8mm × 4mm), and the thermal conductivity was tested using a laser thermal conductivity meter (sample size: 10mm × 10mm × 1.5mm). The test results are shown in Table 1.

[0207] Table 1

[0208]

[0209] As shown in Table 1, the pantograph sliders prepared in the examples generally outperform the comparative examples 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 overall performance of the pantograph sliders. In Comparative Example 1, silica-modified graphene oxide was used as a filler without the introduction of carbon nanotubes. The filler could not form a three-dimensional structure in the matrix, resulting in a decrease in stress dispersion and electrical and thermal conductivity. The pantograph slider prepared in Comparative Example 2 had the lowest mechanical properties because the added filler was not assembled and could not play a synergistic reinforcing role. Instead, it formed agglomerates inside the slider, leading to stress concentration and thus affecting the slider's mechanical properties.

[0210] Based on the same inventive concept, this application also provides a pantograph slider with micro-nano hybrid filler synergistic enhancement, which is prepared by the preparation method of the pantograph slider with micro-nano hybrid filler synergistic enhancement of this application.

[0211] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a pantograph slider with synergistic enhancement by micro / nano hybrid fillers, characterized in that... ,include: Graphene oxide was modified with ethylenediamine to obtain modified graphene oxide. Carbon nanotubes were modified using an acid solution to obtain modified carbon nanotubes. Nano-silica was modified using a silane coupling agent to obtain modified silica; The nano-silica has a particle size of less than or equal to 20 nm; the carbon nanotubes have an outer diameter of 50-80 nm and a length of 5-10 μm; and the graphene oxide has a sheet diameter of greater than 5 μm. The modified graphene oxide, modified nanotubes and modified silica are mixed and electrostatically self-assembled to obtain micro-nano hybrid fillers. During electrostatic self-assembly, carbon nanotubes are first grafted onto the surface of sheet-like graphene oxide, and then nano-silica is dispersed and wrapped on the surface of carbon nanotubes and graphene oxide. The modified graphene oxide, modified carbon nanotubes, and modified silica are mixed and electrostatically self-assembled to obtain a micro / nano hybrid filler, comprising: The modified carbon nanotubes, modified graphene oxide, and modified silica were respectively added to water and dispersed for 1-1.5 hours to obtain the first suspension, the second suspension, and the third suspension, respectively. Mix the first suspension and the second suspension and stir for 10-15 hours, then add the third suspension and continue stirring for 20-28 hours; After stirring, let stand for 4-8 hours, remove the upper liquid, and freeze-dry to obtain micro-nano hybrid filler; The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed, rolled, pressed and sintered to obtain a micro-nano hybrid filler synergistically enhanced pantograph slide plate.

2. The method for preparing the pantograph slider with synergistic enhancement of micro / nano hybrid fillers according to claim 1, characterized in that... The modification of graphene oxide with ethylenediamine to obtain modified graphene oxide includes: Graphene oxide was added to N,N-dimethylformamide and dispersed. Then, N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and ethylenediamine were added and dispersed again to obtain a graphene dispersion. The graphene dispersion was reacted at 55-65℃ for 6-10 hours. After the reaction was completed, the mixture was filtered, washed and dried to obtain modified graphene oxide.

3. The method for preparing the pantograph slider with synergistic enhancement of micro / nano hybrid fillers according to claim 1, characterized in that... The modification of carbon nanotubes using an acid solution includes: The carbon nanotubes were added to a mixture of concentrated nitric acid and concentrated sulfuric acid, and the mixture was reacted at 40-60°C for 3-5 hours before filtration and drying.

4. The method for preparing the pantograph slider with synergistic enhancement of micro / nano hybrid fillers according to claim 1, characterized in that... The modification of nano-silica using a silane coupling agent includes: Nano-silica was pre-soaked in anhydrous ethanol for 30-60 minutes, and then stirred and dispersed to obtain a silica dispersion. The silica dispersion was stirred while water was added dropwise. Then, a mixed solution of silane coupling agent and ethanol was added dropwise to the silica dispersion, and the mixture was stirred at 60-80°C for 6-10 hours. After centrifugation and washing, the mixture was dried.

5. The method for preparing the pantograph slider with synergistic enhancement of 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).

6. The method for preparing the pantograph slider with synergistic enhancement of micro / nano hybrid fillers according to claim 1, characterized in that... The process involves mixing, rolling, pressing, and sintering the micro / nano hybrid filler, pitch coke, graphite powder, and coal tar pitch, including: The micro-nano hybrid filler, pitch coke, graphite powder and coal tar pitch are mixed at 180-220℃ and 800-1200 rpm for 0.5-2 hours to obtain a mixed powder. The mixed powder is compacted and pressed to obtain a green body; The green body is gradually heated to 1000-1150℃ and sintered at 1000-1150℃ for 100-130 hours, then naturally cooled to room temperature.

7. A micro / nano hybrid filler synergistically enhances the pantograph slider, characterized in that, It is prepared by the method of preparing a pantograph slider with synergistic enhancement of micro-nano hybrid fillers as described in any one of claims 1-6.

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