A carbon graphite material for mechanical seals and its preparation method

Abstract

This invention discloses a carbon graphite material for mechanical seals and its preparation method. The method includes: adding 60-80 parts of calcined coke and 5-10 parts of crosslinking agent to a kneading pot and mixing; then adding 20-30 parts of surface modifier to the kneading pot and kneading; after kneading, rolling, crushing and sieving to obtain pressed powder; then carbonizing the pressed powder; and finally crushing, grinding and sieving to obtain modified coke powder; mixing 90-95 parts of binder and 5-10 parts of modifier and adding the mixture to a high-pressure reactor to obtain a modified binder; and then adding 6 parts of... 0-80 parts of spherical carbon and 20-40 parts of oxidant are placed in a beaker and stirred for 2-4 hours. Then, after filtration, washing, and drying, modified spherical carbon is obtained. 60-70 parts of modified coke powder, 5-10 parts of modified spherical carbon, and 1-5 parts of dispersant are added to a kneading pot and mixed. Then, 25-35 parts of modified binder are melted and added to the kneading pot for kneading. The kneaded paste is rolled, crushed, and ground to obtain pressed powder. Then, it is isostatically pressed to obtain a block green body. Finally, it is calcined and graphitized to obtain the carbon-graphite material.

Description

Technical Field

[0001] This invention belongs to the field of materials, and relates to carbon graphite materials, specifically to a carbon graphite material for mechanical seals and its preparation method. Background Technology

[0002] In the early 19th century, mechanical seals were used in mechanical devices to solve the problem of media leakage. Mechanical seals achieve a seal by using spring preload and media pressure to tightly seal the sealing surfaces. Carbon graphite materials possess excellent high-temperature mechanical properties, self-lubricating properties, corrosion resistance, and wear resistance, and are widely used as vulnerable parts for sealing surfaces in mechanical devices. As operating conditions become increasingly demanding (higher speeds, higher pressures, and higher temperatures), ensuring the safety and reliability of mechanical seals requires carbon graphite sealing materials to possess superior mechanical properties, sealing performance, and wear resistance.

[0003] However, during the heat treatment process of carbon-graphite materials, the small organic molecules undergo pyrolysis and condensation reactions, forming large molecules while simultaneously releasing gas molecules. This leads to a decrease in the carbon residue and the formation of internal porosity defects. Consequently, the materials typically require multiple impregnation and firing processes in actual production to meet usage requirements. The outside-to-inside impregnation process inevitably reduces the homogeneity of the material. Currently, domestic products suffer from long production cycles, high costs, and short service life.

[0004] Chinese patents CN103408890A and CN103435967A disclose a method for preparing an Al / carbon-graphite mechanical seal composite material and a method for preparing a Cu / carbon-graphite mechanical seal composite material, respectively. In these methods, aluminum or copper powder is sequentially added to a mixer with graphite, high-carbon materials, and phenolic resin for kneading. The mixture is then crushed, sieved, pressure-molded, and heat-cured to obtain the composite material. While this mechanical seal composite material exhibits high density and hardness due to the addition of metallic raw materials, the hardness of the metal can affect the formation of the graphite friction film and easily lead to abrasive wear, thus affecting the service life of the friction pair.

[0005] Chinese patent CN107540398A discloses a method for preparing a carbon fiber reinforced graphite ring for mechanical seals. This patent utilizes the strength and toughness of carbon fiber-reinforced graphite sealing materials. However, due to the high hardness of carbon fiber, the material has a high coefficient of friction, which affects the service life of the friction pair. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide a carbon graphite material for mechanical seals and its preparation method. This invention has a short production cycle and low cost, and the carbon graphite material obtained has excellent mechanical properties, sealing performance and wear resistance, which can effectively improve service life.

[0007] The technical solution of this invention is implemented as follows:

[0008] A method for preparing a carbon graphite material for mechanical seals specifically includes the following steps:

[0009] (1) Accurately weigh 20-30 parts of surface modifier, D 50 60-80 parts of calcined coke with a thickness of 5-12 μm, and 5-10 parts of crosslinking promoter;

[0010] (2) Add the calcined coke and crosslinking agent from step (1) into a kneading pot and mix. Then heat the pot to 165-200℃ and add the surface modifier into the kneading pot. After kneading, roll the powder, crush and screen it to obtain pressed powder. Then heat the pressed powder to carbonize it. Finally, crush, grind and screen it to obtain modified coke powder.

[0011] (3) Accurately weigh 90-95 parts of adhesive and 5-10 parts of modifier;

[0012] (4) After mixing the binder and modifier in step (3), add them to the high-pressure reactor, introduce air atmosphere, control the pressure inside the reactor to 0.5-2MPa, heat to 200-240℃ at a heating rate of 3-7℃ / min, keep at the temperature for 2-5h, and then cool naturally to room temperature to obtain the modified binder.

[0013] (5) Accurately weigh D 50 60-80 parts of spherical carbon (<3μm) and 20-40 parts of oxidant;

[0014] (6) Place the spherical carbon and oxidant from step (5) in a beaker and stir for 2-4 hours. Then filter, wash and dry to obtain modified spherical carbon.

[0015] (7) Accurately weigh 25-35 parts of modified binder, 60-70 parts of modified coke powder, 5-10 parts of modified spherical carbon, and 1-5 parts of dispersant;

[0016] (8) Add modified coke powder, modified spherical carbon and dispersant to a kneading pot and mix. Then heat to 165-200℃. Then melt the modified binder and add it to the kneading pot to knead. The kneaded paste is rolled, crushed and ground to obtain pressed powder. Then it is isostatically pressed to obtain a block green body. Finally, it is calcined and graphitized to obtain the carbon graphite material.

[0017] Furthermore, the surface modifier is one or more of coal tar, phenolic oil, naphthalene oil, and biomass pitch with a softening point below 90°C; the crosslinking agent is one or more of xylene alcohol, 1,12-diaminododecane, trithiocyanate, methyltrimethoxysilane, and aziridine crosslinking agent.

[0018] Furthermore, the specific steps of step (2) are as follows:

[0019] 2.1: Add the calcined coke and crosslinking agent to the kneading pot and mix at 110-120℃ for 30-60 minutes to remove moisture. The kneading pot speed is 10-30 r / min, alternating between forward and reverse rotation.

[0020] 2.2: Heat to 165-200℃, melt the surface modifier and add it to the kneading pot and knead for 1-2 hours. The kneading pot speed is 30-50 r / min. Keep the lid closed and mix, alternating between forward and reverse rotation.

[0021] 2.3: The mixed paste is transferred to the hopper of the rolling mill and rolled 1 to 3 times at a rolling temperature of 200 to 220°C;

[0022] 2.4: After the rolled sheet material is cooled to room temperature, it is crushed and ground by a mechanical grinding mill, and then pressed into powder with a mesh size of 500 or larger.

[0023] 2.5: The pressed coke powder is filled into a graphite crucible and placed in an atmosphere calcination furnace. The carbonization is carried out in two stages with programmed temperature control: Stage 1: treatment at 200-320℃ in air or oxygen atmosphere for 2-4 hours; Stage 2: treatment at 400-600℃ in argon atmosphere for 2-4 hours; After the heating and holding are completed, the coke is cooled to room temperature with the furnace; The carbonized coke blocks are crushed and ground by a mechanical grinding mill and passed through a 100-200 mesh sieve to prepare modified coke powder.

[0024] Furthermore, the binder is one or more of coal tar, wash oil, anthracene oil, and high residual carbon coal tar pitch with a softening point of 120-150°C.

[0025] Furthermore, the modifier is composed of toluene-insoluble quinoline soluble material (β resin) extracted from raw coal tar pitch coke and one or more of triethylenetetramine, dimethylaminopropylamine and dihexyltriamine, wherein the toluene-insoluble quinoline soluble material accounts for 30-40% of the modifier.

[0026] Furthermore, the spherical carbon is one or more of carbon black, onion carbon, and mesophase carbon microspheres.

[0027] Furthermore, the oxidant is one or more of potassium permanganate, acetic acid, and hydrogen peroxide.

[0028] Furthermore, the dispersant is one or more of oleic acid, tetrahydrofuran, and acetone.

[0029] Furthermore, the specific steps of step (8) are as follows:

[0030] 8.1: Add the modified coke, modified spherical char and dispersant to the kneading pot, mix at 110-120℃ for 30-60 min to remove moisture, and the kneading pot speed is 10-30 r / min, alternating between forward and reverse rotation;

[0031] 8.2: Heat to 165-200℃, melt the modified binder and add it to the kneading pot. Then heat the kneading pot to 210-240℃ and knead for 1-2 hours. The kneading pot speed is 30-50 r / min. Mix with the lid closed, alternating between forward and reverse rotation.

[0032] 8.3: After the mixed paste has cooled to room temperature, it is crushed and ground using a mechanical grinding mill, and the powder is screened into powder with a mesh size of 100-500.

[0033] 8.4: Place the powder in a rubber mold, compact it, then place it in a vacuum bag and evacuate it. Next, place it in a cold isostatic press and press at 100–200 MPa for 20–40 minutes, releasing the pressure at a constant rate of 0.2–0.6 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 4–8 hours to obtain a density of 1.57–1.60 g / cm³. 3 The block green body;

[0034] 8.5: The green body is placed in a graphite crucible filled with granules. The crucible is then placed in a calcining furnace and calcined using a programmed temperature rise method, purging with nitrogen or argon gas at 800–1300℃ for 6–12 hours. After natural cooling to room temperature, a material with a density of 1.65–1.70 g / cm³ is obtained. 3 Calcinated blocks;

[0035] 8.6: The calcined blocks were placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2300–2700℃ for 1–3 hours, then naturally cooled to room temperature, finally yielding a bulk density of 1.78–1.83 g / cm³. 3 Carbon graphite materials.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. This invention uses a surface modifier and a crosslinking promoter to modify calcined coke, thereby constructing a transition layer with surface oxidation activity on the surface of the calcined coke. During the modification process, the surface modifier has a low softening point and excellent fluidity, which allows it to uniformly coat the surface of the calcined coke. The crosslinking promoter is beneficial for promoting the cyclization and aromatization of aliphatic hydrocarbon components in the surface modifier, thereby reducing the escape of small aliphatic hydrocarbon molecules and promoting the construction of the crosslinked oxidation active network interface of the transition layer on the surface of the calcined coke.

[0038] Simultaneously, this invention modifies the binder and spherical carbon. The modified binder surface is rich in CN, CO, and C=O bonds, while the modified spherical carbon surface is rich in CO and C=O bonds. During the preparation of carbon-graphite materials, the small particle size of the spherical carbon allows it to fill the gaps between the modified coke powder particles, reducing porosity and increasing the bulk density of the carbon-graphite material. Furthermore, the active transition layer on the surface of the modified coke powder promotes in-situ cross-linking and carbonization of the modified binder at the interface between the modified coke powder and the binder. The modified spherical carbon filling the gaps between the modified coke powder particles acts as a graphite nucleus substrate, inducing the carbonization and growth of the binder phase. Moreover, the active groups on its surface can rapidly capture molecular chains, further promoting the carbonization of the binder in the gaps between the modified coke powder particles and reducing the escape of volatile components from the binder.

[0039] In addition, the modified binder has excellent interfacial activity, can achieve strong interfacial chemical bonding with modified coke powder and modified spherical carbon, and has a higher degree of molecular crosslinking. It can reduce the escape of light components during the preparation of carbon graphite materials, reduce the generation of pore defects, promote the construction of binder network, and improve the mechanical properties and bulk density of carbon graphite materials.

[0040] 2. The bulk density of the carbon-graphite material obtained by this invention is greater than or equal to 1.78 g / cm³. 3 It has a flexural strength greater than 48MPa, a compressive strength greater than 120MPa, and a friction coefficient less than 0.25. It has excellent mechanical properties, sealing performance and wear resistance, which helps to extend the service life of the friction pair.

[0041] 3. The preparation process of this invention is simple, without the need for impregnation and multiple firings. After pressing and molding, graphitization can be performed directly after one firing to meet application requirements, effectively shortening the production cycle and greatly saving production costs. At the same time, the raw material quality is stable and the batch stability of the production materials is high. Attached Figure Description

[0042] Figure 1 -Infrared spectral curves of calcined coke and modified coke powder in Example 1.

[0043] Figure 2 - ESR curves of calcined coke and modified coke powder in Example 1.

[0044] Figure 3 - A morphology image of the polished surface of the carbon-graphite material prepared in Example 1.

[0045] Figure 4 - Mercury intrusion porosimetry curve of the carbon graphite material prepared in Example 1.

[0046] Figure 5 - A morphology image of the polished surface of the carbon-graphite material prepared in Example 2.

[0047] Figure 6 - Mercury intrusion porosimetry curve of the carbon graphite material prepared in Example 2.

[0048] Figure 7 - A morphology image of the polished surface of the carbon-graphite material prepared in Example 1.

[0049] Figure 8 - Mercury intrusion porosimetry curve of the carbon graphite material prepared in Example 1. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0053] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0054] S2: Prepare 20 parts of biomass pitch with a softening point of 70℃, 3 parts of coal tar, 2 parts of naphthalene oil, 70 parts of calcined coke obtained in S1, 2 parts of xylene alcohol, 2 parts of trithiocyanate, and 3 parts of methyltrimethoxysilane.

[0055] S3: Add the calcined coke, methyltrimethoxysilane, trithiocyanate, and xylene alcohol from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 15 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and naphthalene oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 40 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0056] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 130℃, 5 parts of coal tar, 5 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dimethylaminopropylamine.

[0057] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 30 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 240°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0058] S6: Accurately weigh 10 parts carbon black, 60 parts mesophase carbon microspheres, 10 parts potassium permanganate, and 20 parts hydrogen peroxide.

[0059] S7: Carbon black, mesophase carbon microspheres, potassium permanganate, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The mixture after reaction was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical carbon.

[0060] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 6 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0061] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and a modified binder that melts at a corresponding temperature (90°C higher than the softening point of asphalt) is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at a speed of 50 r / min, with the lid closed, alternating between forward and reverse rotation for 30 minutes. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then pressed into powder with a mesh size of 100–500.

[0062] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.58 g / cm³. 3 The block green blank.

[0063] S11: The green body from S10 is placed in a graphite crucible, which is then filled with metallurgical coke, polystyrene, and polymethyl methacrylate granules. The crucible is then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible is calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.66 g / cm³. 3 Calcinated blocks.

[0064] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.80 g / cm³. 3 Graphite blocks.

[0065] 1. The infrared spectrum and ESR curve of the calcined coke in step S1 and the modified coke powder obtained in step S3 of this embodiment are shown in the figures below. Figure 1 and Figure 2 .

[0066] Depend on Figure 1 It can be seen that the modified coke powder surface has more active oxygen (CO) functional groups, indicating that the modified coke powder surface has high reactivity and easily forms better interfacial bonding with other phases. Furthermore, from... Figure 2 It can be seen that the content of surface active free radicals in modified coke powder is higher than that in calcined coke, which is consistent with the results of infrared analysis. Compared with calcined coke, the superior surface activity of modified coke powder is beneficial to improving the interfacial bonding between coke and binder.

[0067] 2. The polished surface morphology of the carbon-graphite material prepared in this embodiment is shown in Figure 3. As can be seen from the figure, the carbon-graphite material has a dense structure, uniform pore distribution, and small pore size. Furthermore, mercury intrusion porosimetry was performed on the carbon-graphite material prepared in this embodiment to test its pore structure and sealing performance. The mercury intrusion porosimetry curve is shown in Figure 3. Figure 4 As shown in the figure, there is no significant mercury infiltration before the pressure value reaches 100 psi (0.689 MPa), indicating that the carbon graphite material prepared in this embodiment has excellent sealing performance.

[0068] Example 2

[0069] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0070] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0071] S2: Prepare and weigh 20 parts of biomass pitch with a softening point of 80℃, 2 parts of coal tar, 3 parts of phenolic oil, 70 parts of calcined coke obtained in S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, and 1 part of aziridine.

[0072] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, and aziridine from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0073] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 7 parts of coal tar, 3 parts of wash oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0074] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0075] S6: Accurately weigh 30 parts of onion charcoal, 40 parts of mesophase carbon microspheres, 5 parts of potassium permanganate, 5 parts of acetic acid, and 20 parts of hydrogen peroxide.

[0076] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0077] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 6 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0078] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and modified binder asphalt, which has melted at a temperature 90°C higher than the asphalt softening point, is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100–500.

[0079] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.60 g / cm³. 3 The block green blank.

[0080] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.67 g / cm³. 3 Calcinated blocks.

[0081] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.81 g / cm³. 3 Carbon graphite materials.

[0082] The polished surface morphology of the carbon-graphite material prepared in this embodiment is shown in Figure 5. As can be seen from the figure, the carbon-graphite material has a dense structure, uniform pore distribution, and small pore size. Furthermore, mercury intrusion porosimetry was performed on the carbon-graphite material prepared in this embodiment to test its pore structure and sealing performance. The mercury intrusion porosimetry curve is shown in Figure 5. Figure 6 As shown in the figure, only a small amount of mercury seeps in before the pressure reaches 100 psi (0.689 MPa), indicating that the carbon graphite material prepared in this embodiment has excellent sealing performance.

[0083] Example 3

[0084] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0085] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0086] S2: Prepare and weigh 20 parts of biomass pitch with a softening point of 73℃, 2 parts of anthracene oil, 3 parts of naphthalene oil, 70 parts of calcined coke obtained from S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, 1 part of xylene alcohol, and 1 part of trithiocyanate.

[0087] S3: Add the needle coke, 1,12-diaminododecane, methyltrimethoxysilane, xylene alcohol and trithiocyanate from S2 to the kneading pot and mix. Mix at 110℃ for 60 min to remove moisture. The kneading pot rotates at 25 r / min in both directions. Then raise the temperature to 180℃ and introduce the biomass asphalt, anthracene oil and naphthalene oil mixed surface modifier that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt) and knead for 1 h. The kneading pot rotates at 50 r / min, with the lid closed, and mixes in both directions alternately for 30 min. The kneaded paste was transferred to the hopper of a rolling mill and rolled twice at a temperature of 200℃. After cooling to room temperature, the rolled sheets were crushed and ground using a mechanical grinding mill, and then pressed into powder with a mesh size of 500 or larger. The pressed powder was then filled into a graphite crucible and placed in an atmosphere calcination furnace. The furnace underwent two stages of temperature control: Stage 1: 3 hours at 240℃ in air; Stage 2: 4 hours at 500℃ in argon atmosphere. After the heating and holding periods, the mixture was cooled to room temperature in the furnace. The carbonized coke lumps were then crushed and ground using a mechanical grinding mill, and passed through a 160-mesh sieve to obtain modified coke powder.

[0088] S4: Accurately weigh 75 parts of high residual coal tar pitch with a softening point of 135℃, 10 parts of coal tar, 2 parts of wash oil, 3 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0089] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 240°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0090] S6: Accurately weigh 30 parts of onion charcoal, 30 parts of mesophase carbon microspheres, 10 parts of carbon black, 10 parts of potassium permanganate, 2 parts of acetic acid, and 18 parts of hydrogen peroxide.

[0091] S7: Onion charcoal, mesophase carbon microspheres, carbon black, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The mixture after reaction was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical charcoal.

[0092] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 6 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0093] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and a modified asphalt binder at a temperature 90°C higher than the asphalt softening point is introduced. The kneading pan is then heated to 225°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then sieved into powder with a mesh size of 100-500.

[0094] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 200 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.60 g / cm³. 3 The block green blank.

[0095] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.69 g / cm³. 3 Calcinated blocks.

[0096] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.83 g / cm³. 3 Carbon graphite materials.

[0097] The polished surface morphology of the carbon-graphite material prepared in this embodiment is shown in Figure 7. As can be seen from the figure, the carbon-graphite material has a dense structure, uniform pore distribution, and small pore size. Furthermore, mercury intrusion porosimetry was performed on the carbon-graphite material prepared in this embodiment to test its pore structure and sealing performance. The mercury intrusion porosimetry curve is shown in Figure 7. Figure 8As shown in the figure, there is no significant mercury infiltration before the pressure value reaches 100 psi (0.689 MPa), indicating that the carbon graphite material prepared in this embodiment has excellent sealing performance.

[0098] Example 4

[0099] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0100] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0101] S2: Prepare 25 parts of biomass pitch with a softening point of 73℃, 3 parts of anthracene oil, 2 parts of naphthalene oil, 60 parts of calcined coke obtained from S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, 2 parts of xylene alcohol, and 2 parts of trithiocyanate.

[0102] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, xylene alcohol and trithiocyanate from S2 to a kneading pot for mixing. Mix at 110℃ for 60 min to remove moisture. The kneading pot rotates at 25 r / min, alternating between forward and reverse rotation. Then raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, anthracene oil and naphthalene oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min, with the lid closed, alternating between forward and reverse rotation for 30 min intervals. The kneaded paste was transferred to the hopper of a rolling mill and rolled twice at a temperature of 200℃. After cooling to room temperature, the rolled sheets were crushed and ground using a mechanical grinding mill, and then pressed into powder with a mesh size of 500 or larger. The pressed powder was then filled into a graphite crucible and placed in an atmosphere calcination furnace. The furnace underwent two stages of temperature control: Stage 1: 3 hours at 240℃ in air; Stage 2: 4 hours at 500℃ in argon atmosphere. After the heating and holding periods, the mixture was cooled to room temperature in the furnace. The carbonized coke lumps were then crushed and ground using a mechanical grinding mill, and passed through a 160-mesh sieve to obtain modified coke powder.

[0103] S4: Accurately weigh 75 parts of high residual coal tar pitch with a softening point of 135℃, 10 parts of coal tar, 2 parts of wash oil, 3 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0104] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 240°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0105] S6: Accurately weigh 30 parts of onion charcoal, 30 parts of mesophase carbon microspheres, 10 parts of carbon black, 10 parts of potassium permanganate, 2 parts of acetic acid, and 18 parts of hydrogen peroxide.

[0106] S7: Onion charcoal, mesophase carbon microspheres, carbon black, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The mixture after reaction was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical charcoal.

[0107] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 8 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0108] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and a modified asphalt binder at a temperature 90°C higher than the asphalt softening point is introduced. The kneading pan is then heated to 225°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then sieved into powder with a mesh size of 100-500.

[0109] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 200 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.59 g / cm³. 3 The block green blank.

[0110] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.67 g / cm³. 3 Calcinated blocks.

[0111] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.81 g / cm³. 3 Carbon graphite materials.

[0112] Example 5

[0113] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0114] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0115] S2: Prepare 16 parts of biomass pitch with a softening point of 80℃, 2 parts of coal tar, 2 parts of phenol oil, 80 parts of calcined coke obtained in S1, 2 parts of 1,12-diaminododecane, and 3 parts of methyltrimethoxysilane.

[0116] S3: Add the calcined coke, 1,12-diaminododecane, and methyltrimethoxysilane from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0117] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 7 parts of coal tar, 3 parts of wash oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0118] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0119] S6: Accurately weigh 30 parts of onion charcoal, 40 parts of mesophase carbon microspheres, 5 parts of potassium permanganate, 5 parts of acetic acid, and 20 parts of hydrogen peroxide.

[0120] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0121] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 8 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0122] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and modified binder asphalt, which has melted at a temperature 90°C higher than the asphalt softening point, is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100–500.

[0123] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.61 g / cm³. 3 The block green blank.

[0124] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.68 g / cm³. 3 Calcinated blocks.

[0125] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.82 g / cm³. 3 Carbon graphite materials.

[0126] Example 6

[0127] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0128] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0129] S2: Prepare 20 parts of biomass pitch with a softening point of 80℃, 2 parts of naphthalene oil, 3 parts of phenol oil, 70 parts of calcined coke obtained in S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, and 1 part of aziridine.

[0130] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, and aziridine from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0131] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 7 parts of coal tar, 3 parts of wash oil, 5 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, and 2 parts of dihexyltriamine.

[0132] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0133] S6: Accurately weigh 30 parts of onion charcoal, 40 parts of mesophase carbon microspheres, 5 parts of potassium permanganate, 5 parts of acetic acid, and 20 parts of hydrogen peroxide.

[0134] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0135] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 8 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0136] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and modified binder asphalt, which has melted at a temperature 90°C higher than the asphalt softening point, is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100–500.

[0137] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.60 g / cm³. 3 The block green blank.

[0138] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.66 g / cm³. 3 Calcinated blocks.

[0139] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.79 g / cm³. 3 Carbon graphite materials.

[0140] Example 7

[0141] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0142] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0143] S2: Prepare 20 parts of biomass pitch with a softening point of 80℃, 2 parts of naphthalene oil, 3 parts of phenol oil, 70 parts of calcined coke obtained in S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, and 1 part of aziridine.

[0144] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, and aziridine from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0145] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 2 parts of coal tar, 3 parts of wash oil, 5 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0146] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0147] S6: Accurately weigh 30 parts of onion charcoal, 30 parts of mesophase carbon microspheres, 10 parts of potassium permanganate, 10 parts of acetic acid, and 20 parts of hydrogen peroxide.

[0148] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0149] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 8 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0150] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and modified binder asphalt, which has melted at a temperature 90°C higher than the asphalt softening point, is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100–500.

[0151] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.62 g / cm³. 3 The block green blank.

[0152] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.69 g / cm³. 3 Calcinated blocks.

[0153] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.83 g / cm³. 3 Carbon graphite materials.

[0154] Example 8

[0155] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0156] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0157] S2: Prepare 20 parts of biomass pitch with a softening point of 80℃, 2 parts of naphthalene oil, 3 parts of phenol oil, 70 parts of calcined coke obtained in S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, and 1 part of aziridine.

[0158] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, and aziridine from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0159] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 2 parts of coal tar, 3 parts of wash oil, 5 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0160] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0161] S6: Accurately weigh 30 parts of onion charcoal, 35 parts of mesophase carbon microspheres, 10 parts of potassium permanganate, 10 parts of acetic acid, and 15 parts of hydrogen peroxide.

[0162] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0163] S8: Accurately weigh 30 parts of the modified binder obtained from S5, 60 parts of the modified coke powder obtained from S3, 8 parts of the modified spherical carbon obtained from S7, 2 parts of oleic acid, and 2 parts of tetrahydrofuran.

[0164] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and modified binder asphalt, which has melted at a temperature 90°C higher than the asphalt softening point, is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100–500.

[0165] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.62 g / cm³. 3 The block green blank.

[0166] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.69 g / cm³. 3 Calcinated blocks.

[0167] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.83 g / cm³. 3 Carbon graphite materials.

[0168] Example 9

[0169] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0170] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0171] S2: Prepare 20 parts of biomass pitch with a softening point of 80℃, 2 parts of naphthalene oil, 3 parts of phenol oil, 70 parts of calcined coke obtained in S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, and 1 part of aziridine.

[0172] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, and aziridine from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0173] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 2 parts of coal tar, 3 parts of wash oil, 5 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0174] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0175] S6: Accurately weigh 35 parts of onion charcoal, 35 parts of mesophase carbon microspheres, 10 parts of potassium permanganate, 10 parts of acetic acid, and 10 parts of hydrogen peroxide.

[0176] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0177] S8: Accurately weigh 25 parts of the modified binder obtained from S5, 65 parts of the modified coke powder obtained from S3, 10 parts of the modified spherical carbon obtained from S7, 1 part of oleic acid, and 2 parts of tetrahydrofuran.

[0178] S9: Modified coke powder, modified spherical carbon, oleic acid, and tetrahydrofuran are added to a kneading pan and mixed. The mixture is heated to 110°C and mixed for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min, alternating between forward and reverse rotation. After moisture removal, the kneading pan is heated to 180°C, and modified binder asphalt, which has melted at a temperature 90°C higher than the asphalt softening point, is introduced. The kneading pan is then heated to 220°C and kneaded for 1.5 hours at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste cools to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100–500.

[0179] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.61 g / cm³. 3 The block green blank.

[0180] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.68 g / cm³. 3 Calcinated blocks.

[0181] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.81 g / cm³. 3 Carbon graphite materials.

[0182] Example 10

[0183] A method for preparing a carbon graphite material for mechanical seals includes the following steps:

[0184] S1: Industrial-grade needle coke was selected, and the coke powder was screened to obtain coarse powder in the range of 6-60 mesh. The coarse powder was then ground using a mechanical grinding mill to obtain D. 50 The calcined coke is 7 μm in size and has needle-like shape.

[0185] S2: Prepare 20 parts of biomass pitch with a softening point of 80℃, 2 parts of naphthalene oil, 3 parts of phenol oil, 70 parts of calcined coke obtained in S1, 3 parts of 1,12-diaminododecane, 3 parts of methyltrimethoxysilane, and 1 part of aziridine.

[0186] S3: Add the calcined coke, 1,12-diaminododecane, methyltrimethoxysilane, and aziridine from S2 to a kneading pot and mix at 110℃ for 50 min to remove moisture. The kneading pot rotates at 20 r / min in both directions. Then, raise the temperature to 180℃ and introduce a surface modifier made from biomass asphalt, coal tar, and phenolic oil that has melted at the corresponding temperature (90℃ higher than the softening point of asphalt). Knead for 1 h at 50 r / min with the lid closed, alternating between forward and reverse rotation for 30 min intervals. Transfer the kneaded paste to the hopper of a sheeting mill and sheet twice at a temperature of 200℃. After cooling the sheet to room temperature, crush and grind it using a mechanical grinding mill, and then press it into powder with a mesh size of 500 or larger. Fill the pressed powder into a graphite crucible and place it in an atmosphere calcination furnace. Carbonize in two stages using programmed temperature control. Stage 1: Treat at 220℃ in an air atmosphere for 3 h. Second stage: The coke was treated at 550℃ in an argon atmosphere for 4 hours; after heating and holding, it was cooled to room temperature in the furnace; the carbonized coke blocks were crushed and ground by a mechanical grinding mill and passed through a 160-mesh sieve to prepare modified coke powder.

[0187] S4: Accurately weigh 80 parts of high residual coal tar pitch with a softening point of 125℃, 2 parts of coal tar, 3 parts of wash oil, 5 parts of anthracene oil, 3 parts of toluene-insoluble quinoline-soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0188] S5: After the high residual carbon coal tar pitch is simply crushed into powder, it is added to a mixer along with other binders and modifiers and mixed for 60 minutes. The mixed powder is then added to a high-pressure reactor, air is introduced, and the pressure inside the reactor is controlled at 1.0 MPa. The temperature is increased to 220°C at a rate of 5°C / min, and the temperature is maintained for 5 hours before naturally cooling to room temperature to obtain the modified binder.

[0189] S6: Accurately weigh 35 parts of onion charcoal, 35 parts of mesophase carbon microspheres, 10 parts of potassium permanganate, 10 parts of acetic acid, and 10 parts of hydrogen peroxide.

[0190] S7: Onion char, mesophase carbon microspheres, potassium permanganate, acetic acid, and hydrogen peroxide were placed in a beaker and stirred for 2 hours. The resulting mixture was filtered, washed with deionized water until neutral, and then dried at 100°C for 6 hours to obtain modified spherical char.

[0191] S8: Accurately weigh 35 parts of the modified binder obtained from S5, 70 parts of the modified coke powder obtained from S3, 5 parts of the modified spherical carbon obtained from S7, and 1 part of oleic acid.

[0192] S9: Add modified coke powder, modified spherical carbon, and oleic acid to a kneading pan and mix. Heat to 110℃ and mix for 60 minutes to remove moisture. The kneading pan rotates at 15 r / min in both directions. After moisture removal, raise the temperature of the kneading pan to 180℃ and introduce modified binder asphalt that has melted at the corresponding temperature (90℃ higher than the asphalt softening point). Then raise the temperature of the kneading pan to 220℃ and knead for 1.5 hours at a kneading pan speed of 50 r / min.

[0193] Mix under closed lid, alternating between forward and reverse rotation for 30 minutes at intervals. After the kneaded paste has cooled to room temperature, crush and grind it using a mechanical grinder, then screen it into powder with a mesh size of 100–500.

[0194] S10: Place the compressed powder obtained in S9 into a rubber mold, compact it, and then place it in a vacuum bag for vacuuming. Place the vacuum-sealed mold in a cold isostatic press and press it at 150 MPa for 30 minutes, then release the pressure at a constant rate of 0.4 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 6 hours to obtain a density of 1.58 g / cm³. 3 The block green blank.

[0195] S11: The green body from S10 was placed in a graphite crucible, which was then filled with metallurgical coke, ammonium bicarbonate, and polymethyl methacrylate granules. The crucible was then placed in a calcining furnace and calcined at a programmed temperature with argon gas introduced during the process. The crucible was calcined at 1000℃ for 6 hours and then naturally cooled to room temperature, yielding a product with a density of 1.67 g / cm³. 3 Calcinated blocks.

[0196] S12: The calcined block prepared in S11 was placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2500℃ for 1 hour, then naturally cooled to room temperature, finally yielding a bulk density of 1.80 g / cm³. 3 Carbon graphite materials.

[0197] Comparative Example 1

[0198] This embodiment is the same as embodiment 2, except that the binder is not modified in this embodiment. In step S8, the binder is 30 parts, which is composed of 80 parts of high residual coal tar pitch with a softening point of 125℃, 7 parts of coal tar, 3 parts of wash oil, 3 parts of toluene-insoluble quinoline soluble extract from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine.

[0199] Comparative Example 2

[0200] This embodiment is the same as Embodiment 2, except that the spherical carbon is not modified in this embodiment. In step S8, there are 6 parts of spherical carbon, which are composed of 30 parts of onion carbon and 40 parts of mesophase carbon microspheres.

[0201] Comparative Example 3

[0202] This embodiment is the same as Embodiment 2, except that the binder and spherical carbon are not modified in this embodiment. In step S8, the binder is 30 parts, which is composed of 80 parts of high residual coal tar pitch with a softening point of 125℃, 7 parts of coal tar, 3 parts of wash oil, 3 parts of toluene-insoluble quinoline soluble matter extracted from raw coal tar pitch coke, 2 parts of triethylenetetramine and 5 parts of dihexyltriamine; the spherical carbon is 6 parts, which is composed of 30 parts of onion carbon and 40 parts of mesophase carbon microspheres.

[0203] The basic performance parameters of the carbon-graphite materials prepared in Examples 1-10 and Comparative Examples 1-3, and the carbon-graphite material M238 for existing mechanical seals are shown in the table below:

[0204]

[0205] As can be seen from the table above: 1. The basic properties of the carbon-graphite material prepared by this invention are superior to M238, and conform to HB 5366-1986 "Carbon-graphite sealing materials for aviation", namely: bulk density ≥ 1.75 g / cm³ 3 Shore hardness ≥ 50HS, flexural strength ≥ 39MPa, compressive strength ≥ 88MPa, coefficient of thermal expansion ≤ 5.0×10 -6 / K, thermal conductivity ≥30W / m·K, friction coefficient ≤0.25.

[0206] 2. Comparison of Example 2 and Comparative Examples 1-3 shows that in Comparative Example 1, the binder was not oxidatively crosslinked, so the small molecule components in the binder were not captured and escaped, causing a loss in bulk mass and a volume expansion of the bulk, resulting in a lower bulk density of the carbon-graphite material. Furthermore, the interfacial bonding between the binder pitch and aggregate in Comparative Example 1 was poor, leading to inferior mechanical properties compared to Example 2. In Comparative Example 2, the spherical carbon was not surface-modified. Compared to Example 2, the spherical carbon, lacking surface-active treatment, had a weaker ability to promote carbonization in the interstitial micro-regions and a weaker ability to capture volatile molecules in the binder. In Comparative Example 3, neither the binder nor the spherical carbon underwent pretreatment, resulting in poor performance of the prepared graphite bulk material.

[0207] 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 for preparing a carbon-graphite material for mechanical seals, characterized in that, Specifically, the following steps are included: (1) Accurately weigh 20-30 parts of surface modifier, D 50 The product consists of 60-80 parts of calcined coke with a thickness of 5-12 μm and 5-10 parts of a crosslinking agent; the surface modifier is one or more of coal tar, phenol oil, naphthalene oil, and biomass pitch with a softening point below 90℃; the crosslinking agent is one or more of 1,12-diaminododecane, trithiocyanate, methyltrimethoxysilane, and aziridine crosslinking agent. (2) Add the calcined coke and crosslinking agent from step (1) into a kneading pot and mix. Then heat the pot to 165~200℃ and add the surface modifier into the kneading pot. After kneading, roll the powder, crush and screen it to obtain pressed powder. Then heat the pressed powder to carbonize it. Finally, crush, grind and screen it to obtain modified coke powder. (3) Accurately weigh 90-95 parts of binder and 5-10 parts of modifier; the modifier is composed of toluene-insoluble quinoline solubles extracted from raw coal tar pitch coke and one or more of triethylenetetramine, dimethylaminopropylamine and dihexyltriamine, wherein the toluene-insoluble quinoline solubles account for 30-40% of the modifier; (4) After mixing the binder and modifier in step (3), add them to the high-pressure reactor, introduce air atmosphere, control the pressure inside the reactor to 0.5~2 MPa, heat to 200~240 ℃ at a heating rate of 3~7 ℃ / min, keep at the temperature for 2~5 h and then cool naturally to room temperature to obtain the modified binder; (5) Accurately weigh D 50 60-80 parts of spherical carbon with a diameter of < 3 μm, and 20-40 parts of oxidant; (6) Place the spherical carbon and oxidant from step (5) in a beaker and stir for 2-4 hours. Then filter, wash and dry to obtain modified spherical carbon. (7) Accurately weigh 25-35 parts of modified binder, 60-70 parts of modified coke powder, 5-10 parts of modified spherical carbon, and 1-5 parts of dispersant; (8) Add modified coke powder, modified spherical carbon and dispersant to a kneading pot and mix. Then heat to 165~200℃. Then melt the modified binder and add it to the kneading pot to knead. The kneaded paste is rolled, crushed and ground to obtain pressed powder. Then it is isostatically pressed to obtain a block green body. Finally, it is calcined and graphitized to obtain the carbon graphite material.

2. The method for preparing a carbon-graphite material for mechanical seals according to claim 1, characterized in that, The specific steps of step (2) are as follows: 2.1: Add the calcined coke and crosslinking agent to the kneading pot and mix at 110~120 ℃ for 30~60 min to remove moisture. The kneading pot speed is 10~30 r / min, alternating between forward and reverse rotation. 2.2: Heat to 165~200 ℃, melt the surface modifier and add it to the kneading pot and knead for 1~2 hours. The kneading pot speed is 30~50 r / min. Keep the lid closed and mix, alternating between forward and reverse rotation. 2.3: The mixed paste is transferred to the hopper of the rolling mill and rolled 1 to 3 times at a rolling temperature of 200 to 220 ℃; 2.4: After the rolled sheet material is cooled to room temperature, it is crushed and ground by a mechanical grinding mill, and then pressed into powder with a mesh size of 500 or larger. 2.5: The pressed coke powder is filled into a graphite crucible and placed in an atmosphere calcination furnace. The carbonization is carried out in two stages with programmed temperature control: Stage 1: 200~320 ℃ in air or oxygen atmosphere for 2~4 h; Stage 2: 400~600 ℃ in argon atmosphere for 2~4 h; After the heating and holding are completed, the coke is cooled to room temperature with the furnace; The carbonized coke block is crushed and ground into powder using a mechanical grinding mill and passed through a 100~200 mesh sieve to prepare modified coke powder.

3. The method for preparing a carbon-graphite material for mechanical seals according to claim 1, characterized in that, The binder is one or more of coal tar, wash oil, anthracene oil, and high residual carbon coal tar pitch with a softening point of 120~150 ℃.

4. The method for preparing a carbon-graphite material for mechanical seals according to claim 1, characterized in that, The spherical carbon is one or more of carbon black, onion carbon, and mesophase carbon microspheres.

5. The method for preparing a carbon-graphite material for mechanical seals according to claim 1, characterized in that, The oxidant is one or more of potassium permanganate, acetic acid, and hydrogen peroxide.

6. The method for preparing a carbon-graphite material for mechanical seals according to claim 1, characterized in that, The dispersant is one or more of oleic acid, tetrahydrofuran, and acetone.

7. The method for preparing a carbon-graphite material for mechanical seals according to claim 1, characterized in that, The specific steps of step (8) are as follows: 8.1: Add the modified coke, modified spherical char and dispersant to the kneading pot, mix at 110~120 ℃ for 30~60 min to remove moisture, the kneading pot speed is 10~30 r / min, alternating between forward and reverse rotation; 8.2: Heat to 165~200 ℃, melt the modified binder and add it to the kneading pot, then heat the kneading pot to 210~240 ℃ and knead for 1~2 hours. The kneading pot speed is 30-50 r / min. Mix with the lid closed, alternating between forward and reverse rotation. 8.3: After the mixed paste has cooled to room temperature, it is crushed and ground using a mechanical grinding mill, and then screened into powder with a mesh size of 100~500. 8.4: Place the powder in a rubber mold, compact it, then place it in a vacuum bag and evacuate it. Next, place it in a cold isostatic press and press at 100–200 MPa for 20–40 min, releasing the pressure at a constant rate of 0.2–0.6 MPa / s. After releasing the pressure, remove the compressed block and let it stand for 4–8 h to obtain a density of 1.57–1.60 g / cm³. 3 The block green body; 8.5: The green body was placed in a graphite crucible filled with granules. The crucible was then placed in a calcining furnace and calcined using a programmed temperature rise method, with nitrogen or argon gas introduced during the calcination process. The calcination was carried out at 800–1300 °C for 6–12 h, followed by natural cooling to room temperature, yielding a material with a density of 1.65–1.70 g / cm³. 3 Calcinated blocks; 8.6: The calcined blocks were placed in a vacuum graphitization furnace under an inert atmosphere and treated at 2300~2700 ℃ for 1~3 h, then naturally cooled to room temperature, finally yielding a bulk density of 1.78~1.83 g / cm³. 3 Carbon graphite materials.

8. A carbon-graphite material for mechanical seals, characterized in that, The material is prepared according to the method for preparing a carbon-graphite material for a mechanical seal as described in any one of claims 1 to 7.

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