CN107021772B

CN107021772B - Preparation method of carbon fiber reinforced pantograph carbon slide plate

Info

Publication number: CN107021772B
Application number: CN201710249293.0A
Authority: CN
Inventors: 胡萍; 骆旎; 郭阳; 张信
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2017-04-17
Filing date: 2017-04-17
Publication date: 2020-08-25
Anticipated expiration: 2037-04-17
Also published as: CN107021772A

Abstract

The invention discloses a manufacturing method of a carbon fiber reinforced pantograph carbon slide plate, which comprises the following steps: 1) according to the weight percentage of 25-45% of medium temperature asphalt; 35-50 wt% of graphite; 1-15 wt% of carbon fiber; 1-10 wt% of wollastonite; 1-15 wt% of copper powder is selected from the raw materials; 2) continuously kneading and crushing the medium-temperature asphalt and the graphite to obtain a graphite-asphalt kneaded substance, and crushing at a high speed; 3) uniformly mixing the graphite-asphalt kneaded matter, the carbon fiber, the wollastonite and the copper powder in a high-speed mixer, putting the mixture into a mold, and then carrying out hot pressing in a flat vulcanizing machine; 4) roasting the demoulded sample; 5) placing the roasted sample and the impregnated asphalt in a reduced pressure distillation kettle for vacuumizing and pressurizing impregnation; 6) repeating the steps 4) to 5) for multiple times, and performing mechanical treatment after cooling to obtain the carbon fiber reinforced pantograph carbon slide plate. The carbon fiber reinforced pantograph carbon slide plate has excellent comprehensive performances such as conductivity, abrasion resistance, self-lubricating property and the like; the manufacturing method is simple and can realize large-scale production.

Description

Preparation method of carbon fiber reinforced pantograph carbon slide plate

Technical Field

The invention belongs to the technical field of electric locomotives, and particularly relates to a preparation method of a carbon fiber reinforced pantograph carbon slide plate.

Background

The high-speed train for electric traction is in continuous friction contact with a contact net lead through a pantograph carbon slide plate system, leads current on a power grid, and transmits the current to a locomotive power system to maintain normal operation of an electric locomotive. The pantograph carbon slide plate is an electric contact material integrating high conductivity, wear resistance and antifriction performance. The pantograph carbon slide plate is exposed in the natural environment for a long time and often works in dry, humid and even in severe weather such as sand, dust, rain, snow and the like, and in the high-speed running process, the slide plate and a contact net lead continuously generate electric impact and mechanical impact abrasion, so that the pantograph carbon slide plate becomes a part which is replaced most frequently and consumes the most power in an electric locomotive. Therefore, the carbon pantograph slider with excellent comprehensive performance is necessarily selected, and the required conditions are as follows: good conductive performance; excellent abrasion resistance and self-lubricity; the mechanical strength is high, and the vibration and impact load can be withstood without damage; the hardness value is lower than that of the contact wire; the weight is reduced.

At present, the domestic pantograph carbon slide plate is usually manufactured by using graphite, coke powder, carbon black, pitch coke, petroleum coke and the like as main raw materials and a proper binder through the traditional paste hot extrusion, roasting and carbonizing processes. However, carbon and graphite have the common defect of high resistance, the resistance of the base material after roasting is generally 40-80 m omega m, the compressive strength and the impact strength are low, microcracks in the product are more, the product is easy to break, the resistivity is too high, and the performance is reduced due to easy heating, so that the product performance is unstable, the performance of the carbon and graphite base material can not meet the operation requirement of a high-speed motor train unit, and the mass production is difficult to realize.

Disclosure of Invention

The invention aims to overcome the defects and solve the technical problem of providing the preparation method of the carbon fiber reinforced pantograph carbon slide plate with low resistivity, high mechanical strength, excellent abrasion resistance and self-lubricating property.

The technical scheme provided by the invention for solving the technical problems is as follows:

a preparation method of a carbon fiber reinforced pantograph carbon slide plate comprises the following steps:

1) according to the weight percentage of 25-45% of medium temperature asphalt; 35-50 wt% of graphite; 1-15 wt% of carbon fiber; 1-10 wt% of wollastonite; 1-15 wt% of copper powder is selected from the raw materials (the mass ratio of graphite to moderate temperature asphalt is preferably 1: 0.8);

2) continuously kneading and crushing the medium-temperature asphalt and the graphite to obtain a graphite-asphalt kneaded substance, and crushing at a high speed;

3) uniformly mixing the graphite-asphalt kneaded matter, the carbon fiber, the wollastonite and the copper powder in a high-speed mixer, putting the mixture into a mold, then carrying out hot pressing in a flat vulcanizing machine, wherein the hot pressing temperature is 200-350 ℃, the pressure is 15-30 MPa, the pressure maintaining time is 30-40 min, and then demolding;

4) roasting the demoulded sample;

5) placing the roasted sample and the impregnated asphalt in a reduced pressure distillation kettle, heating to 140-180 ℃, preheating for 20min, and then carrying out vacuum pumping and pressurized impregnation, wherein the vacuum degree is 0.1MPa, the pressure is maintained at 0.4-1.0 MPa, and the pressure maintaining time is 30-90 min;

6) repeating the steps 4) to 5) for multiple times, finally roasting according to the step 4), cooling, and then carrying out mechanical treatment to obtain the carbon fiber reinforced pantograph carbon slide plate.

In the scheme, the softening point of the dipping asphalt in the step 5) is 80-90 ℃, the content of quinoline insoluble is less than 0.3%, the content of toluene insoluble is 12-20%, the coking value is 50-55%, and the ash content is less than 0.2%.

In the scheme, the step 2) of obtaining the graphite-asphalt kneaded substance comprises the following specific steps: putting graphite and medium-temperature asphalt into a double-screw kneading granulator, wherein the kneading temperature is 120-170 ℃, and the feeding speed is 120 rpm; the cooled kneaded mass was then pulverized at room temperature using a plastic pulverizer.

In the scheme, the roasting in the step 4) adopts three-stage temperature programming with the temperature of room temperature-200 ℃, 200 ℃ to 800 ℃ and 800 ℃ to 1100 ℃.

In the scheme, the graphite, the carbon fiber, the wollastonite and the copper powder in the step 1) are respectively treated by a silane coupling agent.

In the scheme, the specific steps of the silane coupling agent treatment are as follows:

1) mixing any substance of graphite, carbon fiber, wollastonite or copper powder to be treated with an aminosilane coupling agent according to the mass ratio of 100:0.2-1, and then adding ethanol to mix uniformly;

2) adding acetic acid as a hydrolysis catalyst, and adjusting the pH value to 3.5-5.5;

3) sealing the reaction device, heating to 90-100 ℃ at a heating rate of 2-5 ℃/min, mechanically stirring at the temperature for 4-6 hours, and naturally cooling to room temperature;

4) and (3) placing the compound into a centrifuge, performing suction filtration after centrifugation, and performing vacuum drying on the material subjected to suction filtration, wherein the heat preservation temperature is 100-120 ℃, and the heat preservation time is 8-10 hours, so as to obtain the inorganic substance conjugate.

In the scheme, the graphite in the step 1) is powdery, the average particle size of the graphite is 80-100 meshes, the resistivity of the graphite is 80-130 mu omega-m, and the resistivity of the copper powder in the step 1) is 1-3 × 10^-2μΩ·m。

In the scheme, the moisture content of the medium-temperature asphalt in the step 1) is less than or equal to 0.3%, the ash content is less than or equal to 1%, and the softening point is 85-100 ℃.

In the scheme, the carbon fiber in the step 1) is a short carbon fiber with the length of 1-10mm, and the resistivity of the copper powder in the step 1) is 1-3 × 10^-2μΩ·m。

In the scheme, the wollastonite in the step 1) comprises the following components: the particle size of 1200 meshes accounts for 70-80 wt%; the particle size is 1000 meshes and accounts for 20-30 wt%.

The technical conception of the invention is as follows: wollastonite is added into the carbon sliding plate, and the wollastonite has low coefficient of thermal expansion, so that the shrinkage of a carbon sliding plate material blank of the pantograph can be effectively reduced, and the blank containing the wollastonite also has higher mechanical strength and lower dielectric loss. The addition of a small amount of uniformly dispersed short carbon fibers can improve the flexural strength of the pure carbon integral pantograph slide plate material to more than 20MPa, and the comprehensive performance requirements of the pure carbon integral pantograph slide plate for the high-speed electric locomotive can be met by adding the short carbon fibers and wollastonite. And the dipping process is adopted to further improve the overall strength of the carbon pantograph slider and improve the performance of the carbon pantograph slider.

The invention has the following beneficial effects: (1) aiming at the problems of poor conductivity, low sliding plate strength, high price and short service life of the adopted existing product, the invention provides the pantograph carbon sliding plate which has good conductivity, high mechanical strength, high hardness and good abrasion resistance through double improvement of a formula and a process; (2) the graphite and the asphalt are adopted as base materials, so that the abrasion to the lead is small, the self-lubricating property is good, and the lead is self-abrasion-resistant; (3) the carbon fiber reinforced pantograph carbon slide plate is high in strength, small in friction coefficient and light in weight, and can reduce damage to a contact net; (4) the preparation method is simple in preparation process and low in cost, and is expected to realize industrial application.

Drawings

Fig. 1 is an SEM image at 500 x magnification of the carbon fiber reinforced pantograph carbon slide material of example 1.

Fig. 2 is an SEM image of the carbon fiber reinforced pantograph carbon slide material of example 1, magnified 2000 x.

Fig. 3 is an SEM image at 500 x magnification of the carbon fiber reinforced pantograph carbon slide material of example 5.

Fig. 4 is an SEM image of the carbon fiber reinforced pantograph carbon slide material of example 5, magnified 2000 x.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

The graphite adopted by the invention is powder, the average particle size of the graphite is 80-100 meshes, the resistivity of the graphite is 80-130 mu omega-m, the water content of medium-temperature asphalt is less than or equal to 0.3%, the ash content is less than or equal to 1%, the softening point is 85-100 ℃, the carbon fiber is short carbon fiber, the length of the carbon fiber is 1-10mm, the wollastonite comprises 70-80% of particles with the particle size of 1200 meshes and 20-30% of particles with the particle size of 1000 meshes, and the resistivity of the copper powder is (1-3) × 10^-2μ Ω · m; the softening point of the selected dipping asphalt is 80-90 ℃, the quinoline insoluble content (QI) is less than 0.3 percent, the toluene insoluble content (TI) is 12-20 percent, the coking value is 50-55 percent, and the ash content is less than 0.2 percent.

Example 1

The embodiment provides a preparation method of a carbon fiber reinforced pantograph carbon slide plate, which comprises the following steps:

1. coupling treatment of inorganic fillers

(1) Mixing graphite to be treated with an aminosilane coupling agent according to a mass ratio of 100:0.2-1, and then adding ethanol to mix uniformly;

(2) then adding acetic acid as a hydrolysis catalyst into the reactor, and adjusting the pH value to 5;

(3) sealing the reactor, heating to 90 ℃ at the heating rate of 5 ℃/min, mechanically stirring for 5 hours at the temperature, and naturally cooling to room temperature;

(4) and (3) placing the compound into a centrifuge, centrifuging, performing suction filtration, and performing vacuum drying on the material subjected to suction filtration, wherein the heat preservation temperature is 100 ℃, and the heat preservation time is 8 hours, so as to obtain the inorganic substance conjugate.

Meanwhile, the same steps are adopted for the carbon fiber, the wollastonite and the copper powder for coupling treatment.

2. Preparation of graphite-Pitch kneadate

(1) According to 35.6 wt% of medium temperature asphalt; 44.4 wt% of graphite; 8.27 wt% of carbon fiber; 4.13 wt% of wollastonite; selecting the raw materials with copper powder of 7.6 wt%;

(2) putting the medium-temperature asphalt and graphite into a double-screw kneading granulator, wherein the kneading temperature is 150 ℃, the material pressure is 20MPa, and the feeding speed is as follows: 120 rpm;

(3) when the temperature is cooled to room temperature, crushing the materials by a plastic crusher, and repeating the operations of kneading and crushing for 4 times; and then, grinding the graphite-asphalt kneaded material to 50-100 meshes by using a high-speed stirrer (the rotating speed is 28000r/min) to obtain the graphite-asphalt kneaded material in the step 2).

3. Carbon slide plate for manufacturing carbon fiber reinforced pantograph

(1) Putting the graphite-asphalt kneaded matter, the carbon fiber, the wollastonite and the copper powder into a high-speed stirrer, and stirring at a high speed for 10 minutes to fully and uniformly mix the mixture;

(2) weighing the uniformly mixed materials according to the calculated amount, putting the uniformly mixed materials into a mold, then carrying out hot pressing in a flat vulcanizing machine, keeping the hot pressing temperature at 200 ℃ and the pressure at 20MPa for 30min, then putting the mold and the sample into cooling water, cooling and demolding;

(3) embedding the demolded sample into a crucible filled with quartz sand, isolating air, then placing the sample in a muffle furnace for burning, and adopting temperature programming in three sections: room temperature is 200 deg.C (1h completes heating process), 200 deg.C is 800 deg.C (6h completes heating process), 800 deg.C is 1100 deg.C (1h completes heating process). After cooling, taking out the sample;

(4) placing the impregnated asphalt and the roasted sample in a reduced pressure distillation kettle, heating to 160 ℃, preheating for 20min, vacuumizing and pressurizing for impregnation, wherein the vacuum degree is 0.1MPa, the pressure is maintained at 0.7MPa, and the pressure maintaining time is 60 min;

(5) and (4) roasting the impregnated sample for the second time, wherein the roasting requirement is the same as that in the step (4), and cooling and then carrying out mechanical treatment to obtain a finished product.

Example 2

This example is the same as example 1, except that the ratio of graphite to medium temperature pitch in the step of preparing the graphite-pitch kneaded mass was 1: 1.

example 3

This example is the same as example 1, except that the ratio of graphite to medium temperature pitch in the step of preparing the graphite-pitch kneaded mass was 1: 0.6.

example 4

This example was similar to example 1 except that 29.1 wt% of pitch, 36.4 wt% of graphite, 13.13 wt% of carbon fiber, 6.57 wt% of wollastonite, and 14.8 wt% of copper powder were used.

Example 5

This example is substantially the same as example 1, except that in the process of 3, manufacturing the carbon fiber reinforced pantograph carbon slide plate, the firing of step (3) is performed 4 times, and the impregnation of step (5) is performed 3 times.

Example 6

This example was similar to example 1 except that the pressure was maintained at 1.0MPa and the dwell time was 90 min.

The carbon fiber reinforced pantograph carbon slide plates manufactured in examples 1 to 6 were subjected to performance tests, and the results are shown in the following table:

from fig. 1 to 4, it can be seen that the impregnated carbon fiber reinforced pantograph pan material has a more dense structure.

It is apparent that the above embodiments are only examples for clearly illustrating and do not limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications are therefore intended to be included within the scope of the invention as claimed.

Claims

1. A preparation method of a carbon fiber reinforced pantograph carbon slide plate is characterized by comprising the following steps:

1) according to the weight percentage of 25-45% of medium temperature asphalt; 35-50 wt% of graphite; 1-15 wt% of carbon fiber; 1-10 wt% of wollastonite; 1-15 wt% of copper powder is selected from the raw materials;

3) uniformly mixing the graphite-asphalt kneaded matter, the carbon fiber, the wollastonite and the copper powder in a high-speed mixer, putting the mixture into a mold, then carrying out hot pressing in a flat vulcanizing machine at the hot pressing temperature of 200-350 ℃, the pressure of 15-30 MPa and the pressure maintaining time of 30-40 min, and then demolding;

4) roasting the demoulded sample;

5) placing the roasted sample and the impregnated asphalt in a reduced pressure distillation kettle, heating to 140-180 ℃, preheating for 20min, and then carrying out vacuum pumping and pressure impregnation, wherein the vacuum degree is 0.1MPa, the pressure is maintained at 0.4-1.0 MPa, and the pressure maintaining time is 30-90 min;

2. The process according to claim 1, wherein the impregnated pitch of step 5) has a softening point of 80-90 ℃, a quinoline insoluble content of < 0.3%, a toluene insoluble content of 12-20%, a coking value of 50-55% and an ash content of < 0.2%.

3. The method of claim 1, wherein the step 2) of obtaining the graphite-pitch kneaded mass comprises the following steps: putting graphite and medium-temperature asphalt into a double-screw kneading granulator, wherein the kneading temperature is 120-170 ℃, and the feeding speed is 120 rpm; the cooled kneaded mass was then pulverized at room temperature using a plastic pulverizer.

4. The preparation method of claim 1, wherein the roasting in step 4) adopts three-stage temperature programming, and the temperature is room temperature to 200 ℃, 200 ℃ to 800 ℃ and 800 ℃ to 1100 ℃.

5. The method of claim 1, wherein the graphite, the carbon fiber, the wollastonite, and the copper powder in the step 1) are treated with a silane coupling agent.

6. The method of claim 5, wherein the silane coupling agent treatment comprises the following steps:

4) and (3) placing the compound into a centrifuge, performing suction filtration after centrifugation, and performing vacuum drying on the material subjected to suction filtration, wherein the heat preservation temperature is 100-120 ℃, and the heat preservation time is 8-10 hours, so as to prepare the compound treated by the coupling agent.

7. The preparation method according to claim 1, wherein the graphite in the step 1) is in a powder shape, the average particle size of the graphite is 80-100 meshes, the resistivity of the graphite is 80-130 mu omega ∙ m, and the resistivity of the copper powder in the step 1) is 1-3 × 10m^-2µΩ∙m。

8. The process according to claim 1, wherein the medium-temperature asphalt in step 1) has a moisture content of 0.3% or less, an ash content of 1% or less, and a softening point of 85 to 100 ℃.

9. The method according to claim 1, wherein the carbon fiber in step 1) is a short carbon fiber having a length of 1 to 10mm, and the copper powder in step 1) has an electrical resistivity of 1 to 3 × 10^-2µΩ∙m。

10. The method of claim 1, wherein the wollastonite in the step 1) has a composition of: the particle size of 1200 meshes accounts for 70-80 wt%; the particle size is 1000 meshes and accounts for 20-30 wt%.