CN-118084492-B - High-density high-strength carbon-based composite material with three-layer structure and preparation method thereof

CN118084492BCN 118084492 BCN118084492 BCN 118084492BCN-118084492-B

Abstract

The invention discloses a high-density high-strength three-layer structure carbon-based composite material and a preparation method thereof, wherein the method comprises the steps of mixing active coke with the D50 of 3-6 mu m and microcrystalline graphite powder with the D50 of 10-60 mu m to obtain mixed powder, putting the mixed powder into a kneading pot for kneading, removing water, heating to 160-240 ℃, adding a molten binder or modified binder, adding a modifier, closing a cover for kneading, pouring into a sheet rolling machine for sheet rolling after kneading, crushing, sieving to obtain pressed powder, vacuumizing the pressed powder, performing compression molding and isostatic compaction to obtain a green block, and roasting to obtain the carbon-based composite material. The invention has short production period and low cost, and the prepared carbon-based composite material has a one-layer interface structure, a two-layer brazing structure and a three-layer steel-concrete structure, and the special design of the three-layer structure realizes the double-pipe alignment of 'reinforcing aggregate complementation + micro-active layer construction', thereby effectively improving the volume density, mechanical strength, homogeneity and stability of the carbon-based composite material.

Inventors

TU CHUANJUN
ZHONG ZIHAO
LIU YANLI
REN GAIMEI
LI CHONGWEI
TAN JIAO
XIE YUTONG

Assignees

湖南大学

Dates

Publication Date: 20260505
Application Date: 20240315

Claims (7)

1. The preparation method of the high-density high-strength carbon-based composite material with the three-layer structure is characterized by comprising the following steps of: S1, mixing active coke with the D50 of 3-6 mu m and microcrystalline graphite powder with the D50 of 10-60 mu m to obtain mixed powder, wherein the mass ratio of the active coke to the microcrystalline graphite powder is 40-80:1-20; S2, putting the mixed powder into a kneading pot for kneading, heating to 160-240 ℃ after removing water, adding a molten modified binder, adding a modifier, closing a cover for kneading, and obtaining paste after kneading is finished, wherein the modifier is one or two of coal tar, oleic acid, anthracene oil and pyrolysis oil slurry; S3, pouring the paste into a flaker for flaking, crushing and sieving to obtain pressed powder, vacuumizing the pressed powder, sealing and storing, maintaining the humidity of the pressed powder, performing compression molding and isostatic compaction to obtain a green body block, and finally, placing the green body block in a graphite crucible for roasting to obtain the carbon-based composite material; The modified adhesive is prepared by the following steps: (1) Crushing the binder, and then sieving the crushed binder with a 50-500-mesh sieve to obtain binder powder; (2) Adding binder powder into an organic solvent, wherein the mass ratio of the binder powder to the organic solvent is 1-10:30-300, then placing the mixture in a constant-temperature magnetic stirrer, carrying out ultrasonic treatment at 40-80 ℃ for 30-120 min, carrying out solid-liquid separation, carrying out rotary evaporation at 60-100 ℃ for 30-60 min in a vacuum state, and removing the organic solvent in a soluble part to obtain a soluble substance; (3) And mixing 1-5 parts of soluble matters with 20-40 parts of adhesive powder to obtain the modified adhesive.
2. The method for preparing a high-density high-strength carbon-based composite material with a three-layer structure according to claim 1, wherein the binder is one or more of phenolic resin, mesophase pitch, high-temperature pitch, medium-temperature pitch or low-temperature pitch.
3. The method for preparing a high-density high-strength carbon-based composite material with a three-layer structure according to claim 1, wherein the organic solvent is one or more of acetone, methylal, tetrahydrofuran, toluene, petroleum ether, methylene dichloride or quinoline.
4. The preparation method of the high-density high-strength three-layer structure carbon-based composite material is characterized by comprising the specific steps of setting a kneading temperature to 100-120 ℃, adjusting the rotating speed to 1-10 r/min, uncapping and reversing, putting mixed powder into a kneading pot for dry mixing at 120-160 ℃ for 20-40 min after the kneading temperature reaches a preset temperature, adjusting the rotating speed to 5-50 r/min, uncapping and forward rotating, adjusting the rotating speed to 20-40 r/min after the temperature of the mixed powder reaches the preset temperature, capping and reversing, setting the kneading temperature to 160-240 ℃ after moisture is completely removed, putting a molten modified binder into the mixed powder, simultaneously adding a modifier, adjusting the rotating speed to 20-50 r/min, capping, carrying out wet mixing for 0.5-2 h, carrying out forward rotation and reverse rotation alternately, and obtaining paste after the kneading is finished.
5. The preparation method of the high-density high-strength three-layer structure carbon-based composite material is characterized by comprising the specific steps of pouring the paste into a sheet rolling machine, rolling the sheet for 1-5 times, wherein the thickness of the rolled sheet is 1-5 mm, the temperature of the rolled sheet is 160-240 ℃, the rotating speed is adjusted to be 5-50 r/min, cooling the obtained sheet powder at room temperature for 6-12 h after the rolling is finished, crushing the sheet powder, sieving the sheet powder with a 100-500-mesh sieve, and standing for 6-12 h to obtain the pressed powder.
6. The preparation method of the high-density high-strength three-layer structure carbon-based composite material is characterized by comprising the specific steps of carrying out vacuum pumping treatment on pressed powder in the step S3, then carrying out preforming on the pressed powder at 1-10 MPa to prepare a blank block, wherein the forming temperature is set to be 20-200 ℃, the pressure is maintained for 1-30S, then standing for 6-12 h, then placing the blank block in an isostatic press, pressing for 0.5-1 h at 100-200 MPa, carrying out gradient pressure relief, repeating the isostatic pressure-gradient pressure relief for 1-3 times, then taking out a sample, and then standing for 6-12 h to obtain the blank block with the density of 1.45-1.55 g/cm 3 .
7. The high-density high-strength three-layer structure carbon-based composite material is characterized by being prepared by adopting the preparation method of the high-density high-strength three-layer structure carbon-based composite material disclosed in any one of claims 1-6.

Description

High-density high-strength carbon-based composite material with three-layer structure and preparation method thereof Technical Field The invention belongs to the technical field of carbon-based composite materials, and particularly relates to a high-density high-strength carbon-based composite material with a three-layer structure and a preparation method thereof. Background The carbon-based composite material has a series of excellent performances such as isotropy, good lubricity and abrasion resistance, excellent machining performance, low thermal expansion coefficient, high chemical stability and the like, and is widely applied to the fields of semiconductors, atomic energy reactors, aviation sealing, machinery, powder metallurgy, continuous cast steel, bioengineering and the like. At present, the carbon-based composite material is mainly prepared by taking petroleum coke, artificial graphite powder or calcined pitch coke and the like as aggregates and coal pitch, anthracene oil or phenolic resin and the like as binders through grinding, primary kneading, rolling, cooling, preforming, semi-carbonization, crushing, screening, secondary kneading, rolling, cooling, preforming, isostatic compaction, roasting, dipping, secondary roasting, secondary dipping, tertiary roasting and graphitization to obtain the high-performance carbon-based composite material meeting the requirements. However, the process has the disadvantages of weak mechanical property, poor structural homogeneity, long production period, high cost, low yield and unexpected isotropy of products, a large amount of volatile matters are decomposed and overflowed due to poor consolidation effect of a binder in the heat treatment processes such as roasting, graphitization and the like, a green body has the risks of swelling and cracking in the heat treatment process, the volume shrinkage rate of the carbon-based composite block is large, the shrinkage of the carbon-based composite block at each position is uneven, the porosity of the carbon-based composite material is high, the homogeneity of the blank is poor, and the density and the mechanical property of the carbon-based composite material are further reduced. Compared with the traditional aggregate, the active coke is a novel carbon material with unique spheroidic active structure and special performance, has the characteristics of excellent mechanical and thermal properties, large shrinkage, excellent pressing performance, good structural stability, high purity, good lubricating and wear-resisting properties, excellent isotropy, excellent self-sintering properties, high added value and the like, and is widely applied to the high and new technical fields of solar photovoltaic, metallurgy, chemical industry, atomic energy, aerospace, mechanical sealing, semiconductor industry, nuclear industry and the like. However, as a typical low-density high-strength material, the block prepared by taking activated coke as aggregate has low densification degree, and in addition, the larger volume shrinkage can lead to cracking of a blank body in the roasting process, so that the product is seriously hindered from developing towards the large-size direction, and the comprehensive performance of the finally obtained product is poor. Therefore, it is highly desirable to optimize the aggregate composition, particle size and proportion to improve the density, fracture and compression resistance and other comprehensive properties of the product. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide the high-density high-strength carbon-based composite material with a three-layer structure and the preparation method thereof. The technical scheme of the invention is realized as follows: the preparation method of the high-density high-strength carbon-based composite material with the three-layer structure comprises the following steps: s1, mixing active coke with D50 of 3-6 mu m and microcrystalline graphite powder with D50 of 10-60 mu m to obtain mixed powder; S2, putting the mixed powder into a kneading pot for kneading, heating to 160-240 ℃ after removing water, adding a molten binder or modified binder, adding a modifier, closing a cover for kneading, and obtaining paste after kneading; And S3, pouring the paste into a flaker for flaking, crushing and sieving to obtain pressed powder, vacuumizing the pressed powder, sealing and storing, maintaining the humidity of the pressed powder, performing compression molding and isostatic pressing to obtain a green body block, and finally, placing the green body block in a graphite crucible for roasting to obtain the carbon-based composite material. Further, in the step S1, the mass ratio of the active coke to the microcrystalline graphite powder is 40-80:1-20. Further, the modified adhesive is prepared by the following steps: (1) Crushing the binder, and then sieving the crushed binder with a 50-500-mesh sieve to obtain binde