A mesophase pitch carbon fiber reinforced pantograph carbon slide plate and a preparation method thereof

Abstract

The application discloses a mesophase pitch carbon fiber reinforced pantograph carbon slide plate and a preparation method thereof. The preparation method comprises the following steps: (1) modifying mesophase pitch carbon fibers by using an active agent, and then performing ultrasonic dispersion and vacuum drying to obtain modified mesophase pitch carbon fibers; (2) dry mixing calcined pitch coke, needle coke, artificial graphite powder, N339 carbon black and the modified mesophase pitch carbon fibers to obtain dry powder; (3) adding a binder in a molten state into the dry powder in step (3), and then performing kneading, sheet rolling, back mixing and pressure compression to form a material column; and (4) performing extrusion molding, baking and pressure impregnation of copper on the material column to obtain the mesophase pitch carbon fiber reinforced pantograph carbon slide plate. The pantograph carbon slide plate prepared by the application has low resistivity and good mechanical properties, impact toughness and thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of electrical materials technology, and relates to pantograph carbon sliders, and particularly to a mesophase pitch carbon fiber reinforced pantograph carbon slider and its preparation method. Background Technology

[0002] The pantograph contactor is a crucial current-collecting component in a pantograph-catenary system. Electric locomotives collect current from the contact wire via the contactor, conducting it to the AC drive motor and other electrical equipment on the locomotive, and then guiding it to the ground through the grounding carbon brushes, thus forming a circuit. The pantograph carbon contactor has excellent wear resistance, causes minimal wear on the contact wire, and possesses good conductivity, thus enjoying widespread use.

[0003] However, since pantograph carbon contactors mostly operate under conditions of significant environmental variation, they require high mechanical properties and impact resistance. If these properties are inadequate, cracking and chipping may occur on their surface after a period of use, affecting their lifespan. Furthermore, with increasing demands on electric locomotive speeds and power, the current drawn from the contactors also increases. Therefore, reducing the resistivity of the pantograph carbon contactor has become a technical problem that those skilled in the art wish to solve. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide a mesophase pitch carbon fiber reinforced pantograph carbon slide plate and its preparation method. The pantograph carbon slide plate prepared by this invention has low resistivity and good mechanical properties, impact toughness and thermal stability.

[0005] The technical solution of this invention is implemented as follows:

[0006] A method for preparing a mesophase pitch carbon fiber reinforced pantograph carbon slider includes the following steps:

[0007] (1) Modified mesophase pitch carbon fiber is obtained by using an activator to modify it, followed by ultrasonic dispersion and vacuum drying.

[0008] (2) The calcined pitch coke, needle coke, artificial graphite powder, N339 carbon black and modified mesophase pitch carbon fiber are dry mixed to obtain dry powder.

[0009] (3) Add molten binder to the dry powder in step (3), then mix, roll into sheets, and press back into a column;

[0010] (4) The material column is extruded, baked, and impregnated with molten copper metal under pressure to obtain the mesophase pitch carbon fiber reinforced pantograph carbon slide plate.

[0011] Furthermore, the activator is one or more of oleic acid, linoleic acid, stearic acid, and boric acid; the mass ratio of mesophase pitch carbon fiber to activator is 1~10:100~200.

[0012] Furthermore, in step (1), the ultrasonic dispersion time is 10~30 min; the vacuum drying temperature is 80~100 ℃, and the time is 10~12 h.

[0013] Further, in step (2), the mass ratio of calcined pitch coke, needle coke, artificial graphite powder, carbon black and modified mesophase pitch carbon fiber is (40~50):(30~40):(5~15):(5~10):(5~10).

[0014] Furthermore, in step (2), the dry mixing temperature is 110~130 ℃ and the time is 0.5~1 h.

[0015] Furthermore, the binder is modified asphalt, medium-temperature asphalt, or high-temperature asphalt, preferably modified asphalt.

[0016] Furthermore, in step (3), the amount of binder added is 35-45% of the total mass of the dry powder.

[0017] Further, in step (4), the extrusion temperature is 150~180 ℃ and the extrusion pressure is 10~15 MPa; the impregnation temperature is 1150~1200 ℃ and the impregnation pressure is 10~30 MPa.

[0018] Further, during the roasting in step (4), the temperature is raised from room temperature to 350 ℃, then raised to 450 ℃ at a rate of 3 ℃ / h, and held for 5~30 h; then raised to 550 ℃ at a rate of 2.5 ℃ / h, and held for 5~30 h; then raised to 700 ℃ at a rate of 1.5 ℃ / h, and held for 5~30 h; then raised to 850 ℃ at a rate of 2.0 ℃ / h, and held for 5~30 h; then raised to 900 ℃ at a rate of 7.5 ℃ / h, and held for 5~30 h; then raised to 1200 ℃ at a rate of 10 ℃ / h, and held for 5~30 h.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention uses mesophase pitch carbon fiber as a reinforcing phase. Mesophase pitch carbon fiber has high specific strength, high modulus, and high thermal and electrical conductivity. It forms a second phase in the binder pitch to improve the flexural strength, compressive strength, impact resistance, and electrical conductivity of the pantograph carbon slide plate. At the same time, the fiber surface of the mesophase pitch carbon fiber has a groove structure, which can effectively combine with the binder pitch and aggregate phase to improve the mechanical properties and impact toughness of the pantograph carbon slide plate.

[0021] Furthermore, this invention uses oleic acid and other activators to modify the mesophase pitch carbon fiber, giving the surface of the mesophase pitch carbon fiber a certain number of polar groups, which can effectively increase the chemical bonding points with the aggregate phase, thereby further improving the strength of the pantograph carbon slider. Moreover, the modified mesophase pitch carbon fiber can undergo a physicochemical reaction with the free radicals generated during the pyrolysis stage of the binder pitch, slowing down the generation rate of gaseous small molecule compounds, thereby effectively preventing the generation and propagation of microcracks and improving the thermal stability of the pantograph slider. Attached Figure Description

[0022] Figure 1 - Process flow diagram of the present invention. Detailed Implementation

[0023] A method for preparing a mesophase pitch carbon fiber reinforced pantograph carbon slider, the process flow diagram of which is shown below. Figure 1 As shown, the specific steps include:

[0024] (1) Modified mesophase pitch carbon fiber is obtained by using an activator to modify it, followed by ultrasonic dispersion for 10-30 min, and then vacuum drying at 80-100 ℃ for 10-12 h; the activator is one or more of oleic acid, linoleic acid, stearic acid and boric acid; the ratio of mesophase pitch carbon fiber to activator is 1-10:100-200.

[0025] (2) 40-50 parts of calcined pitch coke, 30-40 parts of needle coke, 5-15 parts of artificial graphite powder, 5-10 parts of carbon black and 5-10 parts of modified mesophase pitch carbon fiber are dry mixed at 110-130 °C for 0.5-1 h to obtain dry powder.

[0026] (3) Add molten binder to the dry powder from step (3), then mix, roll into sheets, and remix and press into a column; wherein the amount of binder added is 35-45% of the total mass of the dry powder;

[0027] (4) The material column is extruded, calcined, and impregnated with molten copper under pressure to obtain the mesophase pitch carbon fiber reinforced pantograph carbon slide plate; wherein, the extrusion temperature is 150~180 ℃, the extrusion pressure is 10~15 MPa; the impregnation temperature is 1150~1200℃, and the impregnation pressure is 10~30 MPa.

[0028] In specific implementation, during the roasting process in step (4), the temperature is raised from room temperature to 350 ℃, then raised to 450 ℃ at a rate of 3 ℃ / h, and held for 5~30 h; then raised to 550 ℃ at a rate of 2.5 ℃ / h, and held for 5~30 h; then raised to 700 ℃ at a rate of 1.5 ℃ / h, and held for 5~30 h; then raised to 850 ℃ at a rate of 2.0 ℃ / h, and held for 5~30 h; then raised to 900 ℃ at a rate of 7.5 ℃ / h, and held for 5~30 h; then raised to 1200 ℃ at a rate of 10 ℃ / h, and held for 5~30 h.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] The calcination process in the following examples is as follows: The temperature is increased from room temperature to 350 °C, then increased to 450 °C at a rate of 3 °C / h, and held for 5 h; then increased to 550 °C at a rate of 2.5 °C / h, and held for 10 h; then increased to 700 °C at a rate of 1.5 °C / h, and held for 20 h; then increased to 850 °C at a rate of 2.0 °C / h, and held for 15 h; then increased to 900 °C at a rate of 7.5 °C / h, and held for 5 h; then increased to 1200 °C at a rate of 10 °C / h, and held for 5 h.

[0031] Example 1

[0032] The method for preparing the mesophase pitch carbon fiber reinforced pantograph carbon slider of this embodiment includes the following steps:

[0033] (1) Five parts of mesophase pitch carbon fiber with a diameter of 8μm were placed in a mixed solution of 100 parts of oleic acid and stearic acid and stirred at a constant temperature of 80 °C for 1 h. Then the mixture was washed twice to obtain modified mesophase pitch carbon fiber.

[0034] (2) The modified mesophase pitch carbon fiber was ultrasonically dispersed in water and then dried under vacuum conditions. The vacuum drying temperature was 100 °C and the drying time was 12 h.

[0035] (3) 5 parts of dried mesophase pitch carbon fiber, 50 parts of calcined pitch coke, 30 parts of needle coke, 10 parts of artificial graphite powder and 5 parts of N339 carbon black were hot-mixed at 110 °C for 1 h to obtain mixed powder (dry powder).

[0036] (4) Add 35% of the dry powder mass of molten modified asphalt to the dry powder, heat to 130 ℃, continue to knead for 1 h, and then roll and remix the mixture to obtain a column of material.

[0037] (5) The material column is extruded at a temperature of 150 ℃ and a pressure of 10 MPa, then roasted according to the above roasting process, and then impregnated with molten copper metal at a temperature of 1200 ℃ and a pressure of 15 MPa to obtain mesophase pitch carbon fiber reinforced electric pantograph carbon slide plate.

[0038] Example 2

[0039] The method for preparing the mesophase pitch carbon fiber reinforced pantograph carbon slider of this embodiment includes:

[0040] (1) Eight parts of mesophase pitch carbon fiber with a diameter of 12μm were placed in a mixed solution of 100 parts of oleic acid and boric acid and stirred at a constant temperature of 80℃ for 1 h. Then the mixture was washed twice to obtain modified mesophase pitch carbon fiber.

[0041] (2) The modified mesophase pitch carbon fiber was ultrasonically dispersed in water and then dried under vacuum conditions. The vacuum drying temperature was 100 °C and the drying time was 12 h.

[0042] (3) 8 parts of dried mesophase pitch carbon fiber, 40 parts of calcined pitch coke, 35 parts of needle coke, 10 parts of artificial graphite powder and 7 parts of N339 carbon black were hot-mixed at 120 °C for 1 h to obtain mixed powder (dry powder).

[0043] (4) Add 40% of the dry powder mass of molten modified asphalt to the dry powder, heat to 140 ℃, continue to knead for 1 h, and then roll and remix the mixture to obtain a column of material.

[0044] (5) The material column is extruded at a temperature of 160 ℃ and a pressure of 12 MPa, then roasted according to the above roasting process, and then impregnated with molten copper metal at a temperature of 1200 ℃ and a pressure of 18 MPa to obtain mesophase pitch carbon fiber reinforced electric pantograph carbon slide plate.

[0045] Example 3

[0046] The method for preparing the mesophase pitch carbon fiber reinforced pantograph carbon slider of this embodiment includes:

[0047] (1) Ten parts of mesophase pitch carbon fiber with a diameter of 15μm were placed in a 100-part mixed solution of linoleic acid and boric acid and stirred at a constant temperature of 80℃ for 1 h. Then the mixture was washed twice to obtain modified mesophase pitch carbon fiber.

[0048] (2) The modified mesophase pitch carbon fiber was ultrasonically dispersed in water and then dried under vacuum conditions. The vacuum drying temperature was 100 °C and the drying time was 12 h.

[0049] (3) 10 parts of dried mesophase pitch carbon fiber, 40 parts of calcined pitch coke, 40 parts of needle coke, 5 parts of artificial graphite powder and 5 parts of N339 carbon black were hot-mixed at 130 °C for 1 h to obtain mixed powder (dry powder).

[0050] (4) Add 45% of the dry powder mass of molten modified asphalt to the dry powder, heat to 150 ℃, continue to knead for 1 h, and then roll and remix the mixture to obtain a column.

[0051] (5) After the material column is extruded and formed at a temperature of 170 ℃ and a pressure of 10 MPa, it is then roasted according to the above roasting process, and then impregnated with molten copper metal at a temperature of 1200 ℃ and a pressure of 22 MPa to obtain mesophase pitch carbon fiber reinforced electric pantograph carbon slide plate.

[0052] Comparative Example 1

[0053] This embodiment is the same as Embodiment 2, except that in this embodiment, the mesophase pitch carbon fiber is not modified, and the mesophase pitch carbon fiber is directly hot-mixed with calcined pitch coke, needle coke, artificial graphite powder and N339 carbon black.

[0054] Comparative Example 2

[0055] This embodiment is the same as Embodiment 2, except that no modified mesophase pitch carbon fiber is added in this embodiment.

[0056] The performance parameters of the pantograph carbon sliding plates obtained in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0057] Table 1. Performance parameters of the pantograph carbon sliding plate obtained in Examples 1-3 and Comparative Examples 1-2.

[0058]

[0059] As can be seen from the table above, compared with Comparative Example 2, Comparative Example 1 added mesophase pitch carbon fiber, which improved the mechanical properties and impact toughness of the pantograph carbon slider to a certain extent, and also reduced the resistivity of the pantograph carbon slider to a certain extent, but the effect was not significant.

[0060] Comparisons of Comparative Examples 1-2 and Examples 1-3 show that modifying mesophase pitch carbon fibers before preparing pantograph carbon contactors effectively improves their mechanical properties and impact toughness, while reducing their resistivity. Furthermore, Examples 1-3 demonstrate that as the amount of modified mesophase pitch carbon fibers added increases, the mechanical properties and impact toughness of the pantograph carbon contactor first increase and then decrease, while the resistivity first decreases and then increases. This indicates that controlling the amount of modified mesophase pitch carbon fibers added is necessary to effectively improve the mechanical properties and impact toughness of the pantograph carbon contactor and reduce its resistivity.

[0061] Finally, it should be noted that the above embodiments of the present invention are merely illustrative examples and not intended to limit the implementation of the invention. Those skilled in the art can make other variations and modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this invention are still within the scope of protection of this invention.

Claims

1. A method of manufacturing a carbon fiber reinforced pantograph carbon slide panel from mesophase pitch, characterized in that, It comprises the following steps: (1) The mesophase pitch carbon fiber is modified by using an active agent, and then is subjected to ultrasonic dispersion and vacuum drying to obtain the modified mesophase pitch carbon fiber; the active agent is one or more of oleic acid, linoleic acid and stearic acid; (2) The calcined pitch coke, needle coke, artificial graphite powder, N339 carbon black and modified mesophase pitch carbon fiber are dry-mixed to obtain a dry powder; the mass ratio of the calcined pitch coke, needle coke, artificial graphite powder, carbon black and modified mesophase pitch carbon fiber is (40-50):(30-40):(5-15):(5-10):(5-10); (3) The dry powder of step (3) is added with a binder in a molten state, and then is subjected to kneading, sheeting and back-mixing to form a column; the binder is modified pitch, medium-temperature pitch or high-temperature pitch; (4) The column is subjected to extrusion molding, baking and pressure impregnation of molten copper to obtain the mesophase pitch carbon fiber reinforced pantograph carbon slide plate; In step (4), the baking is performed at a temperature increasing rate of 3 ℃ / h from room temperature to 350 ℃, then to 450 ℃, and then isothermal for 5-30 h; then the temperature is increased to 550 ℃ at a rate of 2.5 ℃ / h, and then isothermal for 5-30 h; then the temperature is increased to 700 ℃ at a rate of 1.5 ℃ / h, and then isothermal for 5-30 h; then the temperature is increased to 850 ℃ at a rate of 2.0 ℃ / h, and then isothermal for 5-30 h; then the temperature is increased to 900 ℃ at a rate of 7.5 ℃ / h, and then isothermal for 5-30 h; then the temperature is increased to 1200 ℃ at a rate of 10 ℃ / h, and then isothermal for 5-30 h.

2. The method of claim 1, wherein the intermediate pitch pitch carbon fiber reinforced pantograph carbon slide plate is characterized by, The mass ratio of the mesophase pitch carbon fiber and the active agent is 1-10:100-200.

3. The method of claim 1, wherein the intermediate pitch pitch carbon fiber reinforced pantograph carbon slide plate is characterized by, In step (1), the ultrasonic dispersion time is 10-30 min, and the vacuum drying temperature is 80-100 ℃, and the time is 10-12 h.

4. The method of claim 1, wherein the intermediate pitch pitch carbon fiber reinforced pantograph carbon slide plate is characterized by, In step (2), the dry-mixing temperature is 110-130 ℃, and the time is 0.5-1 h.

5. The method of claim 1, wherein the intermediate pitch pitch carbon fiber reinforced pantograph carbon slide plate is characterized by, The binder is modified pitch.

6. A method for preparing a mesophase pitch carbon fiber reinforced pantograph carbon slider according to claim 1 or 5, characterized in that, In step (3), the amount of the binder added is 35-45% of the total mass of the dry powder.

7. The method for preparing a mesophase pitch carbon fiber reinforced pantograph carbon slider according to claim 1, characterized in that, In step (4), the extrusion temperature is 150-180 ℃, and the extrusion pressure is 10-15 MPa; the impregnation temperature is 1150-1200 ℃, and the impregnation pressure is 10-30 MPa.

8. A mesophase pitch carbon fiber reinforced pantograph carbon slide plate, characterized by, The mesophase pitch carbon fiber reinforced pantograph carbon slide plate is prepared by using the preparation method of any one of claims 1-7.

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