Composite graphite cluster / copper-based pantograph slide material and preparation method thereof

Abstract

The present application belongs to the field of interface bonding materials, and particularly relates to a composite graphite cluster / copper-based pantograph slide plate material and a preparation method thereof. The slide plate material comprises a copper base and copper-resin-graphite clusters dispersed in the copper base; in terms of mass percentage, the raw material components of the slide plate material are as follows: copper-resin-graphite clusters 2-6%, and the balance is the copper base. The method comprises the preparation of copper-resin-graphite clusters, mixing, compression molding, and sintering. The present application uses resin to bond a certain amount of copper on the surface of graphite, strengthens the interface between the copper base and graphite, improves the dispersion uniformity of the solid lubricant in the base, and has the advantages of simple process, low cost, low friction coefficient, excellent mechanical properties, and the like.

Description

Technical Field

[0001] This invention belongs to the field of interface bonding materials, specifically relating to a composite graphite cluster / copper-based pantograph sliding plate material and its preparation method. Background Technology

[0002] Currently, the main key issues in the preparation of pantograph materials using powder metallurgy are the poor interfacial bonding between the copper matrix and the solid lubricant (poor compatibility with the metal matrix) and the uniform dispersion of the solid lubricant in the matrix. The poor wettability and tendency to agglomerate between graphite and copper severely affect the performance of the composite material. An effective solution is to reduce the wetting angle between the lubricant and the matrix, thereby improving the interfacial strength. Chemically coating the graphite surface with metal is a common method to improve the sintering performance of copper alloy-graphite composites. Hengqing Li et al. [Hengqing L, Yangzhen L, Baochao Z, et al. On the tribological behaviors of Cu matrixcomposites with different Cu-coated graphite content[J]. Journal of Materials Research and Technology, 2023, 2583-94.] improved the wettability between graphite and copper through chemical copper plating and prepared graphite / copper composites using powder metallurgy, achieving a good match between graphite and copper. They found that the copper-coated graphite content significantly affects the tribological properties of the copper-based composite material. Yiran Wang et al. [Yiran W, Yimin G, Jun T, et al. The study of microstructure characterization: Cu modified Cu-Ni-graphite composite[J]. Composite Interfaces, 2020, 27(3):249-262.] prepared copper-plated graphite using chemical plating and copper-modified copper-nickel graphite composites using powder metallurgy. They studied the interface modification mechanism of the copper coating in the copper-modified copper-nickel graphite composites and found that the modification mechanism of the copper coating in the composites was to reduce the diffusion activity in graphite and the matrix, increase the interfacial diffusion driving force, and change the interfacial connection mode from mechanical connection to a combination of mechanical connection and diffusion connection. The copper coating effectively reduced the diffusion activity in graphite and the matrix and increased the interfacial diffusion driving force.Chu et al. [HY Chu, JF Lin, Experimental analysis of thetribological behavior of electroless nickelcoated graphite particles in aluminum matrix composites under reciprocating motion, Wear, 2000, 126-142.] and Guo et al. [MLT Guo, CYA Tsao, Tribological behavior of aluminum / SiC / nickel-coated graphite hybrid composites, Mater. Sci. Eng. A 333 (2002) 134-145.] studied the use of nickel-plated graphite to improve the tribological properties of graphite / aluminum composites. However, while the above studies improved the interface between the solid lubricant and the copper matrix through alloying or surface modification, the dispersion uniformity of the solid lubricant still needs to be improved. Yi Ding et al. [Yi D, Jianfeng G, Yu H, et al. Study on the microstructure and properties of copper / graphite composites with two-step method and copper-modified graphite[J]. Journal of Physics: Conference Series, 2023, 2639(1).] used chemically plated copper-modified graphite as the core, combined with a two-step mixing method (magnetic stirring + high-energy ball milling) and SPS sintering to prepare samples. The results showed that the copper-plated carbon-copper composite powder prepared by the two-step mixing method did not have the copper plating layer peeled off on the graphite surface. Compared with C / Cu composite powder with the same graphite content, the dispersion of graphite particles in the copper-plated C / Cu composite powder was improved, indicating that the copper plating layer prepared by this process is more dense and uniform.

[0003] In summary, while modifying graphite is one of the effective methods to solve this problem, the chemical plating method is relatively complex and costly. Therefore, there is an urgent need for a graphite modification method that is low in cost and simple to prepare, and that can improve the bonding between graphite and the matrix and the uniformity of graphite distribution in the obtained pantograph sliding plate material. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a composite graphite cluster / copper-based pantograph sliding plate material and its preparation method. This method employs a physical-chemical combination approach, using resin to bond a certain amount of copper to the surface of graphite, thereby enhancing the interface between the copper matrix and graphite and improving the uniformity of solid lubricant dispersion in the matrix. It has advantages such as simple process, low cost, low coefficient of friction, and excellent mechanical properties.

[0005] The technical solution of the present invention is as follows: On one hand, the present invention provides a composite graphite cluster / copper-based pantograph sliding plate material, wherein the sliding plate material comprises a copper matrix and copper-resin-graphite clusters dispersed in the copper matrix; by mass percentage, the raw material composition of the sliding plate material is: 2%~6% copper-resin-graphite clusters, with the remainder being the copper matrix.

[0006] This scheme is further improved, wherein the copper-resin-graphite cluster is prepared by flake graphite powder, copper powder and phenolic resin powder in a mass ratio of 6:3:1.

[0007] This solution is further improved in that the flake graphite powder is 400-800 mesh flake graphite powder; the copper powder and copper matrix are both atomized spherical copper powder with a particle size of 200-400 mesh.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned composite graphite cluster / copper-based pantograph contactor material, comprising the following steps: Preparation of S1 copper-resin-graphite clusters: The resin powder was placed in a container, and anhydrous ethanol was added to completely dissolve the resin powder. Then copper powder and graphite powder were added. After mixing, the mixture was stirred in a water bath at a constant temperature to obtain a mixed slurry. The mixed slurry was dried and cured to obtain a cured product. The cured product was crushed and sieved to obtain copper-resin-graphite clusters. S2 Mixing: Copper-resin-graphite clusters and copper matrix are uniformly mixed with atomized spherical copper powder to obtain mixed powder; S3 Compression Molding: The mixed powder is placed in a mold and cold-pressed. After demolding, a compact is obtained. S4 Sintering: The pressed billet is placed in a vacuum sintering equipment for vacuum sintering, and after cooling in the furnace, copper-based pantograph sliding plate material is obtained.

[0009] This scheme is further improved. In step S1, the control conditions for the water bath constant temperature stirring are: stirring time 3.5h, water bath temperature 60℃; the conditions for drying and curing are: the temperature is controlled at 60℃, which is sufficient to reduce the viscosity of the resin solution and improve its fluidity to facilitate the wetting of copper powder and graphite particles, while being lower than the rapid cross-linking curing temperature of the resin (usually above 80℃), avoiding premature gelation of the resin during stirring, which would lead to uneven mixing. The stirring time of 3.5h is a balanced time point: if the time is too short (e.g., <2h), the resin molecular chains will not be fully extended, and the copper powder and graphite aggregates will not be broken by shear force, resulting in microscopic component segregation; if the time is too long (e.g., >5h), the solvent will evaporate excessively at 60℃, and the viscosity of the solution will increase, which will affect the uniformity of subsequent coating or mixing. The conditions for drying and curing are: drying temperature 60℃, drying time 24h. The drying temperature was set at 60℃, consistent with the stirring temperature. This temperature is in the stage of slow solvent removal, rather than rapid curing. Excessively high drying temperatures (e.g., >80℃) would cause the surface resin to rapidly solidify and form a skin, preventing the internal solvent from escaping. This would easily lead to pores or cracks during subsequent crushing and would also cause stress concentration within the resin. A drying time of 24 hours ensured that the solvent could slowly migrate to the surface through capillary action and completely evaporate, while simultaneously allowing the resin to complete initial molecular chain rearrangement in a near-linear state, providing structural stability for subsequent cluster structures.

[0010] In a further improvement to this scheme, in step S1, the crushed material is sieved through a 100-mesh sieve to obtain copper-resin-graphite cluster powder with a particle size ≤100 mesh.

[0011] This scheme is further improved. In step S3, the cold pressing conditions are: unit pressing pressure of 400~600MPa and holding time of 2-5min. A holding time of 2-5min can effectively expel residual air inside the compact, relieve internal stress, and ensure the density uniformity of the compact in the height direction. Too short a holding time will lead to a "density gradient" phenomenon where the surface of the compact is dense and the interior is loose. Preferably, it is 2~4min.

[0012] This scheme is further improved. In step S4, the vacuum sintering conditions are: sintering temperature of 900-1050℃, preferably 900-1000℃, more preferably 950℃, heating rate of 8℃ / min, and holding time of 2h. During vacuum sintering, the resin components undergo thermal decomposition in the range of 350℃-500℃, generating small gas molecules. The heating rate of 8℃ / min provides sufficient time for these gases to slowly escape from the compact along the pore channels, avoiding defects such as cracking, bubbling, or surface peeling caused by rapid gas generation. The 2h holding time aims to achieve sufficient densification. During this time, grain boundary diffusion and volume diffusion continue, and the pores gradually shrink and spheroidize. If the time is too short (e.g., <1h), diffusion is incomplete, the pores are interconnected, and the material density and electrical and thermal conductivity do not meet the standards; if the time is too long (e.g., >4h), although it will further increase the density, it will induce excessive grain growth, resulting in grain coarsening.

[0013] This scheme is further improved, and the preparation method of composite graphite cluster / copper-based pantograph slider material includes the following steps: Preparation of S1 copper-resin-graphite clusters: Weighed phenolic resin powder was placed in a container, and alcohol was added to completely dissolve the resin powder. Then, atomized spherical copper powder was added, followed by the weighed flake graphite powder while stirring. After the flake graphite powder was added, a water bath constant temperature stirring method was used, and the stirring time was controlled at 3.5 h and the water bath temperature was 60℃. After completion, the mixed solution was placed in an oven to dry at 60℃ for 24 h. Then, the mixture was crushed by grinding rods and sieved through a sieve to obtain 100-mesh copper-resin-graphite cluster powder. S2 Mixing: Copper-resin-graphite clusters and copper-based atomized spherical copper powder are placed in a planetary ball mill and mixed for 2 hours. The ball mill speed is set to 200-300 r / min to achieve uniform mixing and obtain mixed powder. S3 Compression molding: A universal testing hydraulic press was used. Specific test conditions: 10 g of mixed powder was weighed and placed in the compression mold. The unit compression pressure was 600 MPa and the holding time was 2 min. After demolding, a sample with a diameter of 20 mm was made. S4 Sintering: The sample was sintered in a vacuum tube sintering furnace at a temperature of 950℃, a heating rate of 8℃ / min, a holding time of 2h, and then cooled in the furnace.

[0014] The beneficial effects of this invention are as follows: Compared with the prior art, the present invention has the following advantages: (1) This invention innovatively uses copper-resin-graphite clusters to replace traditional flake graphite as a solid lubricant. Through the bonding effect of phenolic resin, graphite and copper powder are pre-formed into a cluster structure, fundamentally solving the industry problem of poor wettability and weak interfacial bonding between graphite and copper matrix. The copper powder in the cluster can achieve metallurgical bonding with the copper matrix, and the carbonaceous interface formed after sintering and carbonization of phenolic resin can achieve bridging between graphite and metal phase, greatly improving the interfacial bonding strength between graphite and copper matrix and avoiding the problem of graphite peeling off during service.

[0015] (2) This invention achieves uniform dispersion of the graphite phase in a copper matrix by prefabricating clusters, effectively suppressing graphite agglomeration and segregation, and significantly improving the uniformity of the material structure. Compared with the traditional method of directly adding flake graphite, the C element in the cluster-modified material is uniformly dispersed in the matrix, rather than just agglomerated at the grain boundaries, and the mechanical and tribological properties of the material are greatly improved.

[0016] (3) The powder metallurgy copper-based pantograph slider material prepared by this invention uses copper-resin-graphite clusters instead of simple flake graphite as a solid lubricant, possessing both excellent mechanical properties and friction-reducing and wear-resistant properties. In one embodiment, it can have a stable and low coefficient of friction of 0.157 at room temperature and a low wear rate of 0.1212 mm. 3 / (N·m), while also possessing high surface hardness (64.29 HV). 0.2 The coefficient of friction was significantly reduced, the mechanical properties were significantly improved, and the wear resistance was greatly improved compared with the traditional flake graphite modified sample with the same amount of graphite. The results showed a high coefficient of friction and a high compressive strength (239.75 MPa). Compared with the traditional flake graphite modified sample with the same amount of graphite, the coefficient of friction was significantly reduced, the mechanical properties were significantly improved, and the wear resistance was greatly improved. This overcomes the problems of weak interfacial bonding between copper and graphite and uneven dispersion of solid lubricant in the matrix.

[0017] (4) The preparation method of the present invention adopts a physical-chemical combined pre-cluster process, which completely abandons the complex chemical plating process, does not require the addition of precious metals, has a short process flow, easy control of process parameters, low production cost, and no pollutants such as electroplating wastewater are generated. It is green and environmentally friendly. The copper-based pantograph sliding plate material prepared by the present invention uses fewer alloying elements, the process is simple, and the production cost is reduced. It is conducive to the large-scale preparation of copper-based pantograph sliding plate materials and the expansion of application fields, and has extremely high engineering application value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 SEM images of flake graphite, the raw material for Examples 1-5; Figure 2 SEM and EDS images of the copper-resin-graphite clusters prepared in this invention; Figure 3 XRD patterns of Examples 3 and 8; Figure 4 Metallographic images of Examples 1-5; Figure 5 Metallographic images of Examples 6-10; Figure 6 SEM and EDS images of Example 3; Figure 7 SEM and EDS images of Example 8; Figure 8 This is a comparison diagram of the friction coefficient curves and wear track interface size diagrams for Examples 1-5; Figure 9 Comparison diagrams of friction coefficient curves and wear track interface size diagrams for Examples 6-10; Figure 10 SEM images of the worn surfaces of the materials in Examples 1-5; Figure 11 SEM images of the worn surfaces of materials in Examples 6-10. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0021] In the following examples and comparative examples, all raw materials used were commercially available industrial-grade products, including: atomized spherical copper powder with a particle size of 200-400 mesh; and high-purity flake graphite powder with a particle size of 400-800 mesh. The phenolic resin powder was P195710 type thermoplastic phenolic resin powder produced by Aladdin Co., Ltd.

[0022] Examples 1-5 (Comparative Examples) Examples 1-5: Atomized spherical copper powder and flake graphite powder were weighed according to the proportions in Table 1, with flake graphite mass fractions ranging from 2-6%. The powders were mixed, pressed, and sintered to prepare experimental samples. Specific preparation methods are as follows: (1) Mixing: Atomized spherical copper powder and flake graphite powder are put into a planetary ball mill and mixed for 2 hours. The speed of the ball mill is set to 200-300 r / min to obtain mixed powder.

[0023] (2) Pressing: A 60T universal testing hydraulic press was used. The specific test parameters were: 10 g of mixed powder was weighed and placed in the pressing mold. The unit pressing pressure was 600 MPa and the holding time was 2 min. After demolding, a sample with a diameter of 20 mm was prepared.

[0024] (3) Sintering: The sintering temperature is 950℃. To prevent oxidation during the sintering process, a vacuum tube sintering furnace is used to sinter the sample. The heating rate is 8℃ / min, the holding time is 2h, and the sample is cooled with the furnace to obtain graphite / copper-based pantograph sliding plate material.

[0025] Examples 6-10 (This invention) In Examples 6-10, the mass ratio of raw material flake graphite, atomized spherical copper powder, and phenolic resin is 6:3:1.

[0026] The preparation method of copper-resin-graphite clusters is as follows: (1) According to the mass ratio of phenolic resin powder and alcohol of 2:8, the weighed phenolic resin powder is put into a beaker, and an appropriate amount of anhydrous ethanol is added to completely dissolve the phenolic resin powder. Then, atomized spherical copper powder is added, and then the weighed flake graphite powder is added while stirring. After the graphite powder is added, the stirring time is controlled to be 3.5 h and the water bath temperature is 60℃, so that the flake graphite powder is evenly dispersed in the phenolic resin powder alcohol solution. After completion, the mixed solution is put into the oven for drying. The temperature is set to 60℃ and the drying time is 24 h. When preparing resin-coated graphite powder, since it is obtained by drying and curing graphite in liquid phase resin alcohol solution, the phenolic resin binds the graphite together. It needs to be crushed by grinding rod and then sieved through a screen to obtain copper-resin-graphite cluster powder of about 100 mesh. The morphology of pure flake graphite is as follows Figure 1 As shown, the morphology of the prepared copper-resin-graphite clusters is as follows: Figure 2 As shown.

[0027] (2) Mixing and pressing: Weigh the atomized spherical copper powder for copper matrix and the above-mentioned agglomerated powder according to the proportion in Table 1, put them into a planetary ball mill and mix for 2 hours. The speed of the ball mill is set to 200-300 r / min. A 60T universal testing hydraulic press is used. Specific test parameters: Weigh 10 g of mixed powder, place it in the pressing mold, the unit pressing pressure is 600 MPa, the holding time is 2 min, and after demolding, a sample with a diameter of 20 mm is made.

[0028] (3) Sintering: The sintering temperature is 950℃. To prevent oxidation during the sintering process, a vacuum tube sintering furnace is used to sinter the sample. The heating rate is 8℃ / min, the holding time is 2h, and the sample is cooled with the furnace to obtain composite graphite cluster / copper-based pantograph sliding plate material.

[0029] Table 1 Mass fraction of each raw material Through Examples 1-10, the following samples were obtained: Example 1 was a sample with 2% by mass of flake graphite; Example 2 was a Cu-based sample with 3% graphite; Example 3 was a Cu-based sample with 4% graphite; Example 4 was a Cu-based sample with 5% graphite; Example 5 was a Cu-based sample with 6% graphite; Example 6 was a Cu-based sample with 2% copper-resin-graphite clusters as a solid lubricant; Example 7 was a Cu-based sample with 3% copper-resin-graphite clusters; Example 8 was a Cu-based sample with 4% copper-resin-graphite clusters; Example 9 was a Cu-based sample with 5% copper-resin-graphite clusters; Example 10 was a Cu-based sample with 6% copper-resin-graphite clusters.

[0030] Example 11 Microstructure Characterization The microstructure and wear surface morphology of the samples were observed using metallographic microscopy and scanning electron microscopy (SEM), and elemental distribution analysis was performed using energy dispersive spectroscopy (EDS). Phase analysis was performed using X-ray diffraction (XRD).

[0031] Figure 1 shows the SEM image of the flake graphite used in the comparative example, which shows that the graphite has a typical layered flake structure; Figure 2 shows the SEM and EDS images of the pre-fabricated copper-resin-graphite clusters, which shows that graphite and copper powder are bonded by resin to form a stable cluster structure, and C and Cu elements are evenly distributed in the clusters.

[0032] Figure 3 shows the XRD patterns of Comparative Example 3 and Example 8. Compared with Example 3, the copper diffraction peak in Example 8 shifts to the right and becomes narrower, indicating that the degree of deformation and defect formation of copper particles is reduced in Example 8, the average microstrain is reduced, and the grain integrity is better. In the XRD phase diagram, the phase composition is as follows: Figure 3 As shown. Figure 4 The metallographic images of Examples 1-5 show that the graphite phase in the Cu-based pantograph material with added flake graphite powder is unevenly distributed in the Cu matrix, and with the increase of the amount added, the graphite phase in the copper matrix exhibits certain agglomeration and segregation.

[0033] Figure 5 The metallographic images of Examples 6-10 show that the graphite distribution uniformity of the copper-based material with added copper-resin-graphite clusters is significantly improved. Furthermore, with the increase of the amount of copper-resin-graphite clusters added, the segregation phenomenon is effectively improved, and the C element is uniformly dispersed on the matrix surface, rather than only distributed at the matrix boundary.

[0034] Figure 6 and Figure 7 The SEM and EDS elemental scan images of Examples 3 and 8 are shown respectively. Comparative analysis reveals that the matrix copper powder used in this invention is atomized spherical copper powder. Figure 6 It can be seen that the copper matrix bonding in Example 3, which added pure flake graphite, is poor because adding excessive graphite would disrupt the matrix continuity; while... Figure 7 It can be seen that the matrix bonding of the sample with added copper-resin-graphite clusters is significantly improved. Example 12 Performance Test

[0035] Density test: The density of the sample was tested using the Archimedes displacement method, according to GB / T 5163-2018 Determination of effective density of metal powder.

[0036] Mechanical property testing: The compressive strength of the specimens was tested using a universal testing machine. The compressive strength measurement was carried out in accordance with GB / T7314-2017 "Metallic Materials - Compression Test at Room Temperature" with a loading rate of 0.5 mm / min. The hardness of the specimens was tested using a micro Vickers hardness tester. The hardness was measured in accordance with GB / T 4340.1-2024 "Metallic Materials - Vickers Hardness Test and Measurement" Part 1, with a load of 0.2 kgf and a holding time of 15 s. The average value of 5 test points was taken.

[0037] Friction and wear performance testing: Dry sliding friction experiments were conducted at room temperature on a GCr15 cylindrical pin with a friction pair of Φ5.6×8.5 mm. The experimental parameters were set as follows: frequency: 2 Hz, stroke: 9 mm, applied load: 50 N, and wear time: 30 min. The friction coefficient was dynamically acquired, and the wear morphology was photographed using a white light interferometer. The data were then imported into Gwydditon software to measure the wear track depth, wear track width, wear volume, and three-dimensional profile of the sample. Finally, the friction coefficient curve and wear profile curve were obtained using Origin software.

[0038] The experimental data for all the above embodiments are shown in Table 2.

[0039] Table 2. Properties of powder metallurgy Cu-based pantograph trolley materials prepared in each embodiment. Based on the experimental results in Table 2 and combined with Figure 8 , 9As can be seen from the friction coefficient curve and wear track interface size diagram, the Cu-based material with copper-resin-graphite clusters prepared according to the present invention exhibits superior mechanical properties and good tribological properties. Compared to the pure flake graphite samples of Examples 1, 2, and 3, the Cu-based materials with copper-resin-graphite clusters prepared according to the present invention in Examples 6, 7, and 8 show a significant reduction in friction coefficient and a substantial improvement in mechanical properties. Meanwhile, Examples 9 and 10, compared to the samples with pure flake graphite, do not show a significant improvement in friction coefficient, but their mechanical properties are significantly enhanced.

[0040] Figure 8 and Figure 9 As can be seen, compared with the materials of Examples 1, 2, and 3, Examples 6, 7, and 8, which added a certain amount of copper-resin-graphite clusters, can effectively reduce the wear track width and depth of the samples, and significantly improve wear resistance. This is because the addition of graphite clusters significantly improves the matrix uniformity of the samples, effectively improving the interfacial bonding between graphite and the copper matrix, and significantly enhancing the frictional performance of the friction surface. Therefore, the copper-resin-graphite clusters prepared in this invention, when added to a copper matrix, exhibit good tribological properties.

[0041] Figure 10 and Figure 11 SEM images of the worn surfaces after dry friction and wear tests in Examples 1-10. The wear mechanism was mainly abrasive wear + oxidative wear. In Examples 4-5, which added 4-6 wt.% pure flake graphite, the scratch surface showed peeling due to the reduced bonding between graphite and the matrix. Although the addition of copper-resin-graphite clusters had a limited effect on improving the wear track depth, it effectively improved the above phenomenon by increasing the bonding between graphite and the matrix. The friction surfaces were mainly characterized by uniform furrows, and the peeling phenomenon was effectively reduced. Example 13

[0042] The difference from Example 8 is that the preparation method of the copper-resin-graphite clusters is as follows: The preparation method of copper-resin-graphite clusters is as follows: (1) According to the mass ratio of phenolic resin powder to alcohol of 2:8, the weighed phenolic resin powder is put into a beaker, and an appropriate amount of anhydrous ethanol is added to completely dissolve the phenolic resin powder. Then, atomized spherical copper powder is added, and then the weighed flake graphite powder is added while stirring. After the graphite powder is added, the stirring time is controlled to be 3.5 h and the water bath temperature is 60℃, so that the flake graphite powder is evenly dispersed in the phenolic resin powder alcohol solution. After completion, the mixed solution is put into the oven for drying. The temperature is set to 60℃ and the drying time is 24 h. When preparing resin-coated graphite powder, since it is obtained by drying and curing graphite in liquid phase resin alcohol solution, the phenolic resin binds the graphite together. It needs to be crushed by grinding rod and then sieved through a screen to obtain copper-resin-graphite cluster powder of about 100 mesh.

[0043] (2) Mixing and pressing: Weigh the atomized spherical copper powder and the above-mentioned clustered powder, put them into a planetary ball mill and mix for 2 hours. The speed of the ball mill is set to 200-300 r / min. A 60T universal testing hydraulic press is used. Specific test parameters: Weigh 10 g of mixed powder, place it in the pressing mold, the unit pressing pressure is 400 MPa, the holding time is 5 min, and after demolding, a sample with a diameter of 20 mm is made.

[0044] (3) Sintering: The sintering temperature was 900℃. To prevent oxidation during the sintering process, a vacuum tube sintering furnace was used to sinter the sample. The heating rate was 8℃ / min, the holding time was 2h, and the sample was cooled with the furnace to obtain a composite graphite cluster / copper-based pantograph sliding plate material with a wear rate of 0.1297mm. 3 / (N·m). Example 14

[0045] The difference from Example 8 is that the preparation method of the copper-resin-graphite clusters is as follows: (1) The preparation method of copper-resin-graphite clusters is as follows: (1) According to the mass ratio of phenolic resin powder to alcohol of 2:8, the weighed phenolic resin powder is put into a beaker, and an appropriate amount of anhydrous ethanol is added to completely dissolve the phenolic resin powder. Then, atomized spherical copper powder is added, and then the weighed flake graphite powder is added while stirring. After the graphite powder is added, the stirring time is controlled to be 3.5 h and the water bath temperature is 60℃, so that the flake graphite powder is evenly dispersed in the phenolic resin powder alcohol solution. After completion, the mixed solution is put into the oven for drying. The temperature is set to 60℃ and the drying time is 24 h. When preparing resin-coated graphite powder, since it is obtained by drying and curing graphite in liquid phase resin alcohol solution, the phenolic resin binds the graphite together. It needs to be crushed by grinding rod and then sieved through a screen to obtain copper-resin-graphite cluster powder of about 100 mesh.

[0046] (2) Mixing and pressing: Weigh the atomized spherical copper powder and the above-mentioned clustered powder, put them into a planetary ball mill and mix for 2 hours. The speed of the ball mill is set to 200-300 r / min. A 60T universal testing hydraulic press is used. Specific test parameters: Weigh 10 g of mixed powder, place it in the pressing mold, the unit pressing pressure is 500 MPa, the holding time is 3 min, and after demolding, a sample with a diameter of 20 mm is made.

[0047] (3) Sintering: The sintering temperature was 1050℃. To prevent oxidation during the sintering process, a vacuum tube sintering furnace was used to sinter the sample. The heating rate was 8℃ / min, the holding time was 2h, and the sample was cooled with the furnace to obtain a composite graphite cluster / copper-based pantograph sliding plate material with a wear rate of 0.1278mm. 3 / (N·m).

[0048] In summary, this invention relates to a powder metallurgy copper-based pantograph sliding plate material that uses copper-resin-graphite clusters instead of pure flake graphite as the solid lubricant. The graphite and copper powder are bonded together with phenolic resin to form graphite clusters, which, when added to the copper matrix, improve the interfacial bonding of the copper-based composite material. This results in a low coefficient of friction and strong wear resistance. This invention can be applied to the preparation of powder metallurgy copper-based pantograph sliding plate materials. By improving the wettability of the solid lubricant to the substrate, it enhances interfacial bonding, reduces wear on parts and energy consumption of equipment, exhibits excellent tribological properties, and has a simple preparation method with easily controllable process parameters.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite graphite cluster / copper-based pantograph sliding plate material, characterized in that, The skateboard material comprises a copper matrix and copper-resin-graphite clusters dispersed in the copper matrix; by mass percentage, the raw material composition of the skateboard material is: 2%~6% copper-resin-graphite clusters, with the remainder being the copper matrix.

2. The composite graphite cluster / copper-based pantograph sliding plate material according to claim 1, characterized in that, The copper-resin-graphite cluster is prepared from flake graphite powder, copper powder, and phenolic resin powder in a mass ratio of 6:3:

1.

3. The composite graphite cluster / copper-based pantograph sliding plate material according to claim 2, characterized in that, The flake graphite powder is 400-800 mesh flake graphite powder; the copper powder and copper matrix are both atomized spherical copper powder with a particle size of 200-400 mesh.

4. A method for preparing the composite graphite cluster / copper-based pantograph slider material according to any one of claims 1-3, characterized in that, Includes the following steps: Preparation of S1 copper-resin-graphite clusters: The resin powder was placed in a container, and anhydrous ethanol was added to completely dissolve the resin powder. Then copper powder and graphite powder were added. After mixing, the mixture was stirred in a water bath at a constant temperature to obtain a mixed slurry. The mixed slurry was dried and cured to obtain a cured product. The cured product was crushed and sieved to obtain copper-resin-graphite clusters. S2 Mixing: Copper-resin-graphite clusters and copper matrix are uniformly mixed with copper powder to obtain a mixed powder; S3 Compression Molding: The mixed powder is placed in a mold and cold-pressed. After demolding, a compact is obtained. S4 Sintering: The pressed billet is placed in a vacuum sintering equipment for vacuum sintering, and after cooling in the furnace, copper-based pantograph sliding plate material is obtained.

5. The preparation method according to claim 4, characterized in that, In step S1, the control conditions for the water bath constant temperature stirring are: stirring time 3.5h, water bath temperature 60℃; the conditions for drying and curing are: drying temperature 60℃, drying time 24h.

6. The preparation method according to claim 4, characterized in that, In step S1, the crushed material is sieved through a 100-mesh sieve to obtain copper-resin-graphite cluster powder with a particle size ≤100 mesh.

7. The preparation method according to claim 4, characterized in that, In step S3, the conditions for cold pressing are: unit pressing pressure 400~600MPa, holding time 2-5 min.

8. The preparation method according to claim 4, characterized in that, In step S4, the conditions for vacuum sintering are: sintering temperature 900-1050℃, heating rate 8℃ / min, and holding time 2h.

9. The preparation method according to claim 4, characterized in that, Includes the following steps: Preparation of S1 copper-resin-graphite clusters: Weighed phenolic resin powder was placed in a container, and alcohol was added to completely dissolve the phenolic resin powder. Then, atomized spherical copper powder was added, followed by the weighed flake graphite powder while stirring. After the flake graphite powder was added, a water bath constant temperature stirring method was used, and the stirring time was controlled at 3.5 h and the water bath temperature was 60℃. After completion, the mixed solution was placed in an oven to dry at 60℃ for 24 h. Then, the mixture was crushed by grinding rods and sieved through a sieve to obtain 100-mesh copper-resin-graphite cluster powder. S2 Mixing: Copper-resin-graphite clusters and copper-based atomized spherical copper powder are placed in a planetary ball mill and mixed for 2 hours. The ball mill speed is set to 200-300 r / min to achieve uniform mixing and obtain mixed powder. S3 Compression molding: A universal testing hydraulic press was used. Specific test conditions: 10 g of mixed powder was weighed and placed in the compression mold. The unit compression pressure was 600 MPa and the holding time was 2 min. After demolding, a sample with a diameter of 20 mm was made. S4 Sintering: The sample was sintered in a vacuum tube sintering furnace at a temperature of 950℃, a heating rate of 8℃ / min, a holding time of 2h, and then cooled in the furnace.

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