Three-dimensional braided composite carbon-based skateboard and preparation method thereof

Abstract

The present invention discloses a three-dimensional woven composite carbon-based skateboard and a preparation method thereof. The preparation method comprises weaving carbon fibers and copper wires into a composite three-dimensional braided body having a porous cross-section through a three-dimensional braiding process, filling the pores with a mixture of graphite powder and copper powder or copper-plated graphite powder to prepare a preform, and subjecting the heat-treated preform to chemical vapor deposition, resin impregnation and curing, carbonization, and heat treatment to obtain a three-dimensional woven composite carbon-based skateboard. The three-dimensional woven composite carbon-based skateboard of the present invention has relatively higher mechanical properties, high electrical conductivity, low resistivity, and high wear resistance, and can be better applied to rail transit vehicles as a pantograph skateboard material.

Description

Technical Field

[0001] The present invention belongs to the technical field of pantograph slide plate material preparation for rail transit vehicles, and in particular relates to a three-dimensional braided composite carbon-based slide plate and a preparation method thereof. Background Art

[0002] The pantograph slide is a key component for rail transit vehicles (electric locomotives, subways, etc.) to obtain electricity from the power grid. It is installed on the top of the train pantograph and is in direct contact with the contact network. The slide is in long-term friction with the contact network wire during train operation, so the pantograph slide material must have properties such as conductivity, impact resistance, wear resistance, and arc resistance. At present, the pantograph slides widely used at home and abroad are mainly pure carbon slides and copper-impregnated carbon slides. The problem with pure carbon slides is that they have poor mechanical strength and are easy to break and fall off; copper-impregnated carbon slides have better conductivity, but insufficient impact resistance, are prone to collapse, and have high cost and maintenance costs. With the rapid development of high-speed electric locomotives, the current performance of pantograph slide materials has gradually failed to meet the needs of railway development, and has become one of the bottlenecks in the development of electric locomotives.

[0003] In recent years, researchers have designed a carbon fiber composite material that combines the advantages of pure carbon and copper-impregnated carbon materials. It reduces conductor wear, improves mechanical strength, and reduces resistivity to a certain extent, making it an ideal material for next-generation pantograph slides. However, the three-dimensional copper network structure in carbon fiber composite slides is still relatively poorly continuous and has a low overall density, which cannot effectively improve the material's conductivity. Furthermore, issues such as strength and wear resistance persist. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a three-dimensional woven composite carbon-based skateboard with relatively higher mechanical properties, low resistivity, and high wear resistance, and a preparation method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A method for preparing a three-dimensional braided composite carbon-based skateboard comprises the following steps:

[0007] (1) Preparation of a composite three-dimensional braid: carbon fibers and copper wires are mixed and woven into a composite three-dimensional braid having a porous cross-section through a three-dimensional braiding process;

[0008] (2) Preparation of a pantograph slide preform: filling the pores of the composite three-dimensional braided body with a mixture of graphite powder and copper powder or copper-plated graphite powder to obtain a pantograph slide preform;

[0009] (3) Heat treatment of the preform: After evacuating the pantograph slide preform, nitrogen is injected to break the vacuum, and then electrically heated to 900°C to 960°C. Argon is then filled in, and the preform is further heated to 950°C to 1000°C and kept warm. The preform is then cooled to 300°C to 320°C, and the argon is exhausted and then cooled to room temperature.

[0010] (4) Chemical vapor deposition: chemical vapor deposition is performed on the preform obtained after the above heat treatment using a carbon source gas and a diluent gas at a deposition temperature of 860°C to 900°C, and then heated to 950°C to 1000°C for heat treatment;

[0011] (5) Impregnation curing-carbonization: The deposited preform obtained in step (4) is heated to 60°C to 70°C under vacuum conditions, and then the preform is impregnated with a mixture of furan resin and curing agent at an impregnation pressure of 1.5MPa to 2MPa, and then the temperature is raised to 180°C to 200°C for heat preservation and curing, and the heat-cured preform is heated to 830°C to 900°C for carbonization treatment;

[0012] (6) Heat treatment: After evacuating the carbonized preform, nitrogen is injected to break the vacuum, and then it is electrically heated to 900℃~960℃. Then, argon is filled and heated to 950℃~1000℃. After keeping the temperature for 2h~3h, it is cooled to 300℃~320℃. After the argon is discharged, it is cooled to room temperature. After machining and cutting, a three-dimensional braided composite carbon-based skateboard is obtained.

[0013] The method for preparing the three-dimensional braided composite carbon-based skateboard is preferably such that in step (1), the mass percentage of the copper wire contained in the composite three-dimensional braided body is 20% to 50%, the mass percentage of the carbon fiber is 50% to 80%, and the pore density is 2 pores / cm 2 ~6 holes / cm 2 .

[0014] The preparation method of the above-mentioned three-dimensional woven composite carbon-based skateboard, preferably, in step (1), the three-dimensional weaving process adopts a special-section weaving process, using a layered weaving method. After the first layer is woven, the tension is maintained by the yarn guide component, and the next layer is woven, and a composite three-dimensional woven body is obtained by weaving layer by layer; the carbon fiber is a carbon fiber tow, and the diameter of the carbon fiber tow meets the requirements of carbon fiber wire T300 or T700; the wire diameter of the copper wire meets the wire diameter of 0.1mm~0.2mm.

[0015] The preparation method of the above-mentioned three-dimensional woven composite carbon-based skateboard, preferably, the special-shaped cross-section weaving process includes the following process: weaving carbon fiber and copper wire in a layered weaving manner from bottom to top by a weaving machine, each layer is woven into a braid by at least 3 groups of yarns, and the direction of each group of yarns has an angle with the molding direction, so that the braids of each layer are cross-linked with each other to form a multi-layer cross-linked and interlayer interlocking structure, the weaving machine adopts a weaving machine with 48 spindles to 128 spindles, first weaving a 1mm to 2mm thick flat surface as the base, and then by adding or reducing yarns and setting the cross-linking position of each layer, a part of the yarns are not involved in the weaving, so that a part of the plane layer has a braided body and a part is empty, and the tension is maintained by the yarn guide component, and then the next layer is weaved, and it is gradually woven into a preset cross-sectional shape. The last layer is weaved with a 1mm to 2mm thick plane. When weaving layer by layer, the boundary is not hollowed out, and there is a 1mm to 2mm thick braided body, so that a 1mm to 2mm thick rectangle is formed on the periphery of the final cross-section, so that the composite three-dimensional braided body structure is fixed.

[0016] In the above-mentioned method for preparing a three-dimensional woven composite carbon-based skateboard, preferably, in step (1), the porous shape of the cross-surface of the composite three-dimensional woven body includes one or more of hexagonal, circular and square holes; the cross-surface of the composite three-dimensional woven body is a porous honeycomb structure.

[0017] The above-mentioned method for preparing a three-dimensional woven composite carbon-based skateboard, preferably, in step (2), in the mixture of graphite powder and copper powder, the mass ratio of the graphite powder to the copper powder is 2 to 3:1 to 3, the graphite powder is flake graphite powder or granular graphite powder, the particle size of the graphite powder is not greater than 150 microns, and the copper powder is red copper powder, and the particle size of the copper powder is not greater than 300 microns.

[0018] In the above-mentioned method for preparing a three-dimensional woven composite carbon-based skateboard, preferably, in step (2), the particle size of the copper-plated graphite powder is not greater than 200 microns, and the mass fraction of copper in the copper-plated graphite powder is 30% to 60%, and the mass fraction of graphite is 40% to 70%.

[0019] In the above-mentioned method for preparing a three-dimensional woven composite carbon-based skateboard, preferably, in step (4), the volume ratio of the carbon source gas to the dilution gas is 0.8-1.1:0.9-1, the carbon source gas includes one of propylene and natural gas, the dilution gas includes one of nitrogen and hydrogen, the deposition time is 100h-150h, and the heat treatment time is 3h-4h.

[0020] In the preparation method of the above-mentioned three-dimensional woven composite carbon-based skateboard, preferably, in step (5), the mass ratio of furan resin to curing agent in the mixture of furan resin and curing agent is 2:1, the impregnation time is 2h~3h, the insulation curing time is 1h~2h; the heating time is 110h~120h, and the carbonization treatment time is 4h~5h.

[0021] In the preparation method of the above-mentioned three-dimensional woven composite carbon-based skateboard, preferably, in step (2), the filling method is vacuum filling, and the vacuum filling pressure is 0.4MPa~0.6MPa; in step (3), the insulation time is 2h~3h, and the cooling is natural cooling; in step (6), the insulation time is 2h~3h, and the cooling is natural cooling.

[0022] As a general technical concept, the present invention also provides a three-dimensional woven composite carbon-based skateboard prepared by the above-mentioned preparation method.

[0023] In step (3) of the preparation method of the present invention, the temperature of continued heating after filling with argon is higher than the temperature of electric heating before filling with argon.

[0024] In step (6) of the preparation method of the present invention, the temperature of continued heating after filling with argon is higher than the temperature of electric heating before filling with argon.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. In order to solve the problems of collapse and breakage of current carbon skateboards, the current copper mesh or copper wire is constructed in a stacked manner with carbon fiber. The composite carbon skateboard of the present invention is three-dimensionally woven with carbon fiber and copper wire into a carbon skateboard matrix, forming a continuous copper wire structure in the carbon skateboard. Compared with the stacked structure of copper mesh, the three-dimensionally woven matrix has better continuity of copper wire in three directions, which improves the conductivity of the overall structure. In addition, the fiber filaments and copper wires are interlaced in three directions, and the stability of the structure is improved.

[0027] 2. A simple three-dimensional woven structure has certain gaps within the three-dimensional body. If you want to produce a large cross-section dense solid body, the manufacturing cost is high and it is difficult. The present invention designs the cross section into a porous structure, which reduces the cross-sectional woven area. The honeycomb structure has strong stability and can reduce the possibility of structural collapse.

[0028] 3. In view of the porous structure designed by the present invention, a carbon-copper mixture is filled in the pores, which improves the wear resistance of the material and the continuity of the network structure of the three-dimensional braided body and the density of the material, further improves the conductivity, reduces the bow-net wear of the carbon slide plate, and improves the wear resistance of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the structure of the composite three-dimensional braided body in Example 1 of the present invention.

[0030] Figure 2 This is a schematic structural diagram of the pantograph slide preform in Example 1 of the present invention.

[0031] Legend:

[0032] 1. Composite three-dimensional braid; 2. Cross section; 3. Mixed powder of graphite powder and copper powder. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby. The materials and instruments used in the following examples are all commercially available.

[0034] Example 1:

[0035] A method for preparing a three-dimensional braided composite carbon-based skateboard of the present invention comprises the following steps:

[0036] (1) Preparation of composite three-dimensional braided body 1: Carbon fibers and copper wires are mixed and woven into a composite three-dimensional braided body 1 having a porous cross section 2 by a three-dimensional braiding process, such as Figure 1 The three-dimensional weaving process specifically adopts the special-shaped cross-section weaving process, using the layered weaving method. After the first layer is woven, the yarn guide component maintains the tension and maintains the shape of the porous cross-section, and then weaves the next layer. The density of 1.1g / cm is obtained by weaving layer by layer. 3 The composite three-dimensional braided body 1 contains 35% copper wire and 65% carbon fiber by mass, wherein the carbon fiber is T300 and has a density of 1.6 g / cm 3 , elastic modulus 230GPa, fiber diameter 7μm, copper wire is red copper wire, wire diameter is 0.1mm. The porous cross-section shape of the composite three-dimensional braided body 1 is honeycomb, and the mesh pore density is 3.5 holes / cm 2 .

[0037] (2) Preparation of pantograph slide preform: Fill the holes of the composite three-dimensional braided body 1 with a mixed powder 3 of graphite powder and copper powder in a mass ratio of 3:1 (fill until full) by vacuuming to obtain a pantograph slide preform, such as Figure 2 The pressure of the exhaust equipment is 0.4 MPa, the graphite powder is 150 micron granular graphite powder, and the copper powder is 200 micron copper powder.

[0038] (3) Heat treatment of the preform: The preform from step (2) was placed in a high-temperature heat treatment furnace. After evacuation, nitrogen was injected to break the vacuum (three times in a row). The furnace was then electrically heated to 900°C and filled with argon. The furnace was further heated to 950°C and kept at this temperature for two hours. The preform was then cooled to 300°C in a natural environment. The argon was then removed and cooled to room temperature. The three-dimensional composite braid generates internal stress during the braiding process. To ensure the stability of the preform, the braid was subjected to high-temperature heat treatment to eliminate the internal stress.

[0039] (4) Chemical vapor deposition: Chemical vapor deposition was performed on the preform obtained by the above heat treatment using propylene and nitrogen in a volume ratio of 1:1. The deposition temperature was 900°C and the deposition time was 100 hours. After deposition, the preform was heated to 950°C and heat treated for 3 hours.

[0040] (5) Impregnation and curing: The deposited preform is placed in an impregnation tank, vacuumed and heated to 60°C. The mixture of furan resin and curing agent is sucked into the impregnation tank by vacuuming and pressurizing. The mass ratio of furan resin to curing agent in the mixture of furan resin and curing agent is 2:1. Then the pressure is increased to 2 MPa and the pressure is maintained for impregnation for 2 hours. The temperature is then raised to 200°C and kept for curing for 1 hour.

[0041] (6) Carbonization: The preform after impregnation and curing is placed in a carbonization furnace, and the preform is carbonized after vacuuming. The temperature is 900°C, the heating process is 110 hours, and then the heat preservation carbonization treatment is carried out for 4 hours.

[0042] (7) The carbonized preform was placed in a high-temperature heat treatment furnace, evacuated and then nitrogen was injected to break the vacuum (three times in a row), then electrically heated to 900°C and filled with argon, and then heated to 950°C. After keeping warm for 2 hours, it was cooled to 300°C in a natural environment, and after the argon was exhausted, it was cooled to room temperature. After machining and cutting, a three-dimensional braided composite carbon-based skateboard was obtained, and the properties are shown in Table 1.

[0043] Table 1 Performance parameters of the three-dimensional braided composite carbon-based skateboard prepared in Example 1

[0044] Test parameter name Test results <![CDATA[Skateboard density (g / cm 3 )]]> 2.4 <![CDATA[Impact toughness (J / cm 2 )]]> 0.9 Resistivity (uΩ·m) 1 Compressive strength (MPa) 220 Rockwell hardness (HR5 / 150) 120 <![CDATA[Contact wire wear ratio (mm 2 / 10,000 pantograph operations)]]> 0.012 Slide plate height wear ratio (mm / 10,000 locomotive kilometers) 0.3 Skateboard weight wear ratio (g / 10,000 locomotive kilometers) 32

[0045] The above description is only a preferred embodiment of the present invention and does not constitute any formal limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the spirit and technical solution of the present invention, use the methods and technical contents disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a three-dimensional braided composite carbon-based skateboard, characterized in that: The following steps are involved: (1) Preparation of composite three-dimensional braided body: carbon fiber and copper wire are mixed and woven into a composite three-dimensional braided body with a porous cross section through a three-dimensional braiding process; (2) Preparation of a pantograph slide preform: filling the pores of the composite three-dimensional braided body with a mixture of graphite powder and copper powder or copper-plated graphite powder to obtain a pantograph slide preform; (3) Heat treatment of the preform: After evacuating the pantograph slide preform, nitrogen is injected to break the vacuum, and then electrically heated to 900°C to 960°C. Argon is then filled in, and the preform is further heated to 950°C to 1000°C and kept warm. The preform is then cooled to 300°C to 320°C, and the argon is exhausted and then cooled to room temperature. (4) Chemical vapor deposition: chemical vapor deposition is performed on the preform obtained after the above heat treatment using carbon source gas and diluent gas, the deposition temperature is 860℃~900℃, and then heated to 950℃~1000℃ for heat treatment; (5) Impregnation curing-carbonization: The deposited preform obtained in step (4) is heated to 60°C to 70°C under vacuum conditions, and then the preform is impregnated with a mixture of furan resin and curing agent at an impregnation pressure of 1.5MPa to 2MPa, and then the temperature is raised to 180°C to 200°C for heat preservation and curing. The heat-cured preform is heated to 830°C to 900°C for carbonization treatment; (6) Heat treatment: After evacuating the carbonized preform, nitrogen is injected to break the vacuum, and then electrically heated to 900℃~960℃, and then filled with argon and continued to heat to 950℃~1000℃. After keeping the temperature for 2h~3h, it is cooled to 300℃~320℃, and after exhausting the argon, it is cooled to room temperature. After machining and cutting, a three-dimensional braided composite carbon-based skateboard is obtained; In step (1), the mass percentage of the copper wire contained in the composite three-dimensional braided body is 20% to 50%, the mass percentage of the carbon fiber is 50% to 80%, and the pore density is 2 pores / cm 2 ~6 holes / cm 2 ; In step (1), the three-dimensional weaving process adopts a special-section weaving process and uses a layered weaving method. After the first layer is weaved, the tension is maintained by a yarn guide component, and the next layer is weaved, and a composite three-dimensional braided body is obtained by weaving layer by layer; the carbon fiber is a carbon fiber tow, and the diameter of the carbon fiber tow meets the requirements of carbon fiber T300 or T700; the wire diameter of the copper wire meets the wire diameter of 0.1mm to 0.2mm.

2. The method for preparing a three-dimensional braided composite carbon-based skateboard according to claim 1, characterized in that: The special-section braiding process includes the following process: braiding carbon fiber and copper wire in a layered weaving manner from bottom to top through a braiding machine, each layer is interwoven into a braid by at least 3 groups of yarns, and the direction of each group of yarns has an angle with the forming direction, so that the braids of each layer are cross-linked with each other to form a multi-layer cross-linked and interlayer interlocking structure. The braiding machine uses a braiding machine with 48 to 128 spindles, first weaving a 1mm to 2mm thick flat surface as a base, and then by adding or reducing yarns and setting the cross-linking position of each layer, a part of the yarn is not involved in the weaving, so that a part of the plane layer has a braided body and a part is empty, and the tension is maintained by the yarn guide component, and then the next layer is weaved, and it is gradually woven into a preset cross-sectional shape. The last layer is weaved with a 1mm to 2mm thick plane. When weaving layer by layer, the boundary is not hollowed out, and there is a 1mm to 2mm thick braided body, so that a 1mm to 2mm thick rectangle is formed on the periphery of the final cross-section, so that the composite three-dimensional braided body structure is fixed.

3. The method for preparing a three-dimensional braided composite carbon-based skateboard according to claim 1, characterized in that: In step (1), the porous shape of the cross-surface of the composite three-dimensional braided body includes one or more of hexagonal, circular and square shapes; and the cross-surface of the composite three-dimensional braided body is a porous honeycomb structure.

4. The method for preparing a three-dimensional braided composite carbon-based skateboard according to any one of claims 1 to 3, characterized in that: In step (2), in the mixture of graphite powder and copper powder, the mass ratio of the graphite powder to the copper powder is 2-3:1-3, the graphite powder is flake graphite powder or granular graphite powder, the particle size of the graphite powder is not greater than 150 microns, the copper powder is red copper powder, and the particle size of the copper powder is not greater than 300 microns; the particle size of the copper-plated graphite powder is not greater than 200 microns, and the mass fraction of copper in the copper-plated graphite powder is 30%-60%, and the mass fraction of graphite is 40%-70%.

5. The method for preparing a three-dimensional braided composite carbon-based skateboard according to any one of claims 1 to 3, characterized in that: In step (4), the volume ratio of the carbon source gas to the dilution gas is 0.8-1.1:0.9-1, the carbon source gas includes one of propylene and natural gas, the dilution gas includes one of nitrogen and hydrogen, the deposition time is 100h-150h, and the heat treatment time is 3h-4h.

6. The method for preparing a three-dimensional braided composite carbon-based skateboard according to any one of claims 1 to 3, characterized in that: In step (5), the mass ratio of furan resin to curing agent in the mixture of furan resin and curing agent is 2:1, the impregnation time is 2h~3h, the heat preservation and curing time is 1h~2h; the heating time is 110h~120h, and the carbonization treatment time is 4h~5h.

7. The method for preparing a three-dimensional braided composite carbon-based skateboard according to any one of claims 1 to 3, characterized in that: In step (2), the filling method is vacuum filling, and the vacuum filling pressure is 0.4MPa to 0.6MPa; in step (3), the insulation time is 2h to 3h, and the cooling is natural cooling; in step (6), the insulation time is 2h to 3h, and the cooling is natural cooling.

8. A three-dimensional braided composite carbon-based skateboard made by the preparation method according to any one of claims 1 to 7.

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