CN117776764A - Graphite composite material and preparation method and application thereof - Google Patents
Graphite composite material and preparation method and application thereof Download PDFInfo
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- CN117776764A CN117776764A CN202311832343.XA CN202311832343A CN117776764A CN 117776764 A CN117776764 A CN 117776764A CN 202311832343 A CN202311832343 A CN 202311832343A CN 117776764 A CN117776764 A CN 117776764A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 123
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 82
- 239000010439 graphite Substances 0.000 title claims abstract description 82
- 239000002131 composite material Substances 0.000 title claims abstract description 77
- 238000002360 preparation method Methods 0.000 title claims abstract description 24
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 39
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 229910010271 silicon carbide Inorganic materials 0.000 claims abstract description 26
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 16
- 239000004952 Polyamide Substances 0.000 claims abstract description 15
- 239000002253 acid Substances 0.000 claims abstract description 15
- 229920002647 polyamide Polymers 0.000 claims abstract description 15
- 239000002994 raw material Substances 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 41
- 239000002002 slurry Substances 0.000 claims description 39
- 238000001035 drying Methods 0.000 claims description 29
- 238000005087 graphitization Methods 0.000 claims description 21
- 239000011230 binding agent Substances 0.000 claims description 19
- 239000011268 mixed slurry Substances 0.000 claims description 17
- 238000000465 moulding Methods 0.000 claims description 16
- 239000007789 gas Substances 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 11
- 238000010000 carbonizing Methods 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 6
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims description 6
- 239000004005 microsphere Substances 0.000 claims description 6
- 239000011331 needle coke Substances 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 235000009496 Juglans regia Nutrition 0.000 claims description 5
- 238000000746 purification Methods 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- 235000020234 walnut Nutrition 0.000 claims description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 4
- 239000000460 chlorine Substances 0.000 claims description 4
- 229910052801 chlorine Inorganic materials 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 4
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 4
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 4
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 3
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 3
- 239000005711 Benzoic acid Substances 0.000 claims description 3
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 3
- 239000001099 ammonium carbonate Substances 0.000 claims description 3
- 235000010233 benzoic acid Nutrition 0.000 claims description 3
- 238000003763 carbonization Methods 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000011780 sodium chloride Substances 0.000 claims description 3
- 235000002639 sodium chloride Nutrition 0.000 claims description 3
- 238000005192 partition Methods 0.000 claims description 2
- 235000019422 polyvinyl alcohol Nutrition 0.000 claims description 2
- 240000007049 Juglans regia Species 0.000 claims 1
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 claims 1
- 125000000914 phenoxymethylpenicillanyl group Chemical group CC1(S[C@H]2N([C@H]1C(=O)*)C([C@H]2NC(COC2=CC=CC=C2)=O)=O)C 0.000 claims 1
- 239000013078 crystal Substances 0.000 abstract description 17
- 238000005452 bending Methods 0.000 abstract description 7
- 229920005575 poly(amic acid) Polymers 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 16
- 239000011148 porous material Substances 0.000 description 8
- 238000010298 pulverizing process Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 229920001721 polyimide Polymers 0.000 description 6
- 241000758789 Juglans Species 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 239000004372 Polyvinyl alcohol Substances 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 description 3
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 3
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- BYEAHWXPCBROCE-UHFFFAOYSA-N 1,1,1,3,3,3-hexafluoropropan-2-ol Chemical compound FC(F)(F)C(O)C(F)(F)F BYEAHWXPCBROCE-UHFFFAOYSA-N 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 239000007767 bonding agent Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The application relates to a graphite composite material and a preparation method and application thereof. The preparation raw materials of the graphite composite material comprise the following components in percentage by mass: 55% -75% of carbon-based aggregate, 15% -25% of pore-forming agent and 15% -30% of polyamic acid. The graphite composite material comprises carbon-based aggregate, pore-forming agent and polyamide acid in a specific proportioning relationship, so that the graphite composite material has excellent tensile strength, bending strength and through hole rate, and the efficiency of removing carbon wrappage in the growth of silicon carbide crystals of the graphite composite material can be improved.
Description
Technical Field
The application relates to the field of materials, in particular to a graphite composite material and a preparation method and application thereof.
Background
Silicon carbide (SiC) crystals are representative materials of third-generation wide-band-gap semiconductor materials, have the characteristics of large forbidden band width, high critical breakdown electric field strength, high carrier saturation migration speed, high thermal conductivity and good chemical stability, and have wide application in the fields of microelectronics and optoelectronics. Currently, the vapor transport method (PVT) method is the most mature method applied in the preparation method of silicon carbide crystals, and is the only preparation method capable of meeting the requirements of commercial silicon carbide substrates.
In the production of SiC crystals by PVT, carbon particles generated by volatilization of SiC powder are easily transported to the crystal surface with an air flow and enter the crystal as growth proceeds, causing so-called "carbon inclusions" and inducing micropipe or dislocation defects. Is an important factor causing low quality of crystal growth. Therefore, a porous graphite separator is generally used in the prior art to filter the growth atmosphere of the silicon carbide crystal and block tiny carbon particles in the silicon carbide crystal, so that the quality of the prepared SiC crystal is improved. In the early stage of the production process, the porous graphite separator is used as a porous material, the content of the silicon atmosphere, namely the Si/C ratio of the atmosphere, can be adjusted, the formation of silicon drops is inhibited, and the crystal quality is improved. However, the porous graphite separator manufactured by the traditional process has carbon residues and unavoidable pulverization of aggregate in the high-temperature use process, so that the porous graphite separator becomes a new source of carbon wrappage, and further the quality of silicon carbide single crystals is affected.
Thus, the conventional technology has yet to be improved.
Disclosure of Invention
Based on the above, it is necessary to provide a graphite composite material having excellent tensile strength, bending strength and porosity, and a preparation method and application thereof, and the specific scheme is as follows:
in one aspect, the present application provides a graphite composite material, which comprises the following preparation raw materials in percentage by mass: 55% -75% of carbon-based aggregate, 15% -25% of pore-forming agent and 15% -30% of binder, wherein the binder comprises polyamide acid.
In one embodiment, the pore-forming agent comprises at least one of walnut powder, PVB, ammonium bicarbonate, sodium chloride, benzoic acid, PVP, PVA, PS microspheres, PMMA microspheres.
In one embodiment, the particle size of the carbon-based aggregate is 50-300 μm; and/or
The carbon-based aggregate includes needle coke.
In another aspect, the present application also provides a method for preparing a graphite composite material, including the steps of:
mixing the preparation raw materials of the graphite composite material and a solvent to prepare mixed slurry;
and (3) sequentially carrying out forming treatment, carbonization treatment and graphitization treatment on the mixed slurry to prepare the graphite composite material.
In one embodiment, before the forming process, the method further comprises drying the mixed slurry, wherein the drying process meets at least one of the following conditions (1) - (2):
(1) The temperature of the drying treatment is 40-180 ℃;
(2) The drying treatment time is 20-60 min.
In one embodiment, the step of drying process comprises the steps of:
performing first drying treatment on the mixed slurry at 40-45 ℃ for 8-12 min to obtain first dried slurry;
performing second drying treatment for 18-22 min at 50-55 ℃ on the first dried slurry to obtain second dried slurry;
and carrying out third drying treatment for 18-22 min at 70-75 ℃ on the second drying slurry to obtain dried slurry, and carrying out subsequent forming treatment.
In one embodiment, the molding process satisfies at least one condition of (1) to (3):
(1) The pressure of the molding treatment is 0.5 mpa-10 mpa;
(2) The temperature of the molding treatment is 260-300 ℃;
(3) The molding treatment time is 20-90 min.
In one embodiment, the step of carbonizing comprises the steps of:
carrying out first roasting treatment on the slurry subjected to the forming treatment at the constant temperature of 300-400 ℃ for 10-15 hours to obtain first roasting slurry;
performing second roasting treatment on the first roasting slurry at the constant temperature of 450-650 ℃ for 20-30 hours to obtain second roasting slurry;
and carrying out third roasting treatment on the second roasting slurry at the constant temperature of 700-1100 ℃ for 50-90 hours to obtain third roasting slurry.
In one embodiment, the graphitizing treatment satisfies at least one condition of (1) to (3):
(1) The graphitization treatment temperature is 2000-2300 ℃;
(2) The graphitization treatment time is 20-70 h;
(3) After the step of carbonizing and before the step of graphitizing, the method further comprises the steps of:
introducing inert gas to raise the temperature to 1700-1900 ℃, and introducing purified gas to carry out purification treatment;
optionally, the purified gas comprises at least one of freon and chlorine.
The application also provides a preparation method of the silicon carbide material, which comprises the following steps:
preparing silicon carbide on the partition board by adopting a gas phase transmission method;
the separator comprises a graphite composite material as described above or a graphite composite material produced by the method of producing a graphite composite material as described above.
The preparation method of the graphite composite material comprises the steps of carbon-based aggregate, pore-forming agent and binder in a specific proportioning relationship, wherein the binder comprises polyamide acid, and polyamide acid is selected as a binder component, so that on one hand, the polyamide acid and the carbon-based aggregate have good miscibility matching degree, and each component can form a good bonding system, thereby improving the mechanical strength of the graphite composite material, and on the other hand, the graphite composite material can be solidified and converted into a polyimide film with high temperature resistance and compactness in the sintering process; therefore, on one hand, the polyimide film can wrap the carbon-based aggregate, and the probability that the carbon wrap is separated from the graphite composite material due to pulverization of the graphite composite material can be reduced; on the other hand, a certain pore-forming agent is added, the porosity of the graphite composite material is improved, the pore size distribution is uniform, and all components are coordinated, so that the graphite composite material has excellent tensile strength, bending strength and porosity, and when the graphite composite material is used as a separator for preparing silicon carbide, good mechanical properties can be maintained in the growth of silicon carbide crystals, the pulverization is not easy, the probability that carbon wrappage is separated from the graphite composite material due to the pulverization of the graphite composite material can be reduced, and the occurrence probability of the carbon wrappage is reduced.
Drawings
Fig. 1 is a diagram showing metallographic results of the graphite composite material prepared in example 1.
Detailed Description
In order to facilitate an understanding of the present application, a more complete description of the present application will be provided below, along with preferred embodiments of the present application. This application may, however, be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. The indefinite articles "a" and "an" preceding an element or component in this application are not limited to the requirements of the number of elements or components (i.e. the number of occurrences). Thus, the use of "a" or "an" should be interpreted as including one or at least one, and the singular reference of an element or component includes the plural reference unless the amount clearly dictates otherwise. The meaning of "a plurality of" means at least two, e.g., two, three, etc., unless explicitly defined otherwise.
Except where shown or otherwise indicated in the operating examples, all numbers expressing quantities of ingredients, physical and chemical properties, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". For example, therefore, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can be varied appropriately by those skilled in the art utilizing the teachings disclosed herein seeking to obtain the desired properties. The use of numerical ranges by endpoints includes all numbers subsumed within that range and any range within that range, e.g., 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, 5, and the like.
In the prior art, the prepared porous graphite separator is inevitably pulverized in the aggregate in the high-temperature use process, and technicians propose to prepare the graphite composite material by bonding the aggregate by adopting a bonding agent. However, during further practical research and development, it was found that: the binder will leave more pores and carbon residue after graphitization, making the porous graphite separator a new source of "carbon wrap".
Thus, the applicant found through a great deal of creative experimental study that: the polyamide acid is selected as the binder component, on one hand, the compatibility and matching degree of the polyamide acid and the carbon-based aggregate are good, and each component can form a good bonding system, so that the mechanical strength of the graphite composite material can be improved, and on the other hand, the polyamide acid can be solidified and converted into a high-temperature-resistant compact polyimide film in the sintering process; by regulating specific components in specific proportion relation in the graphite composite material, the graphite composite material has excellent tensile strength, bending strength and through hole rate, and when the graphite composite material is used as a separator to prepare silicon carbide, the excellent mechanical property can be maintained in the growth of silicon carbide crystals, the pulverization is difficult, the probability that the graphite composite material is pulverized to form a carbon wrapper to be separated from the graphite composite material can be reduced, and the occurrence probability of the carbon wrapper is reduced.
An embodiment of the present application provides a graphite composite material, which comprises the following preparation raw materials in percentage by mass: 55% -75% of carbon-based aggregate, 15% -25% of pore-forming agent and 15% -30% of binder, wherein the binder comprises polyamide acid.
The preparation method of the graphite composite material comprises the steps of carbon-based aggregate, pore-forming agent and binder in a specific proportioning relationship, wherein the binder comprises polyamide acid, and polyamide acid is selected as a binder component, so that on one hand, the polyamide acid and the carbon-based aggregate have good miscibility matching degree, and each component can form a good bonding system, thereby improving the mechanical strength of the graphite composite material, and on the other hand, the graphite composite material can be solidified and converted into a polyimide film with high temperature resistance and compactness in the sintering process; therefore, on one hand, the polyimide film can wrap the carbon-based aggregate, and the probability that the carbon wrap is separated from the graphite composite material due to pulverization of the graphite composite material can be reduced; on the other hand, a certain pore-forming agent is added, the porosity of the graphite composite material is improved, the pore size distribution is uniform, and all components are coordinated, so that the graphite composite material has excellent tensile strength, bending strength and through hole rate, and when the graphite composite material is used as a separator for preparing silicon carbide, good mechanical properties can be maintained in the growth of silicon carbide crystals, the pulverization is not easy, the probability that carbon wrappage is separated from the graphite composite material due to the pulverization of the graphite composite material can be reduced, and the occurrence probability of the carbon wrappage is reduced.
It is to be understood that when a range of values is disclosed herein, the range is to be regarded as continuous, and includes both the minimum and maximum values for the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range description features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to include any and all subranges subsumed therein.
The range of the carbon-based aggregate is 55% -75%, i.e., the minimum value and the maximum value of the range of 55% -75%, and each value between the minimum value and the maximum value are taken. Specific examples include, but are not limited to, the point values in the embodiments: 55%, 55.5%, 56%, 56.5%, 57%, 57.5%, 58%, 58.5%, 59%, 59.5%, 60%, 60.5%, 61%, 61.5%, 62%, 62.5%, 63%, 63.5%, 64%, 64.5%, 65%, 65.5%, 66%, 66.5%, 67%, 67.5%, 68%, 68.5%, 69%, 69.5%, 70%, 70.5%, 71%, 71.5%, 72%, 72.5%, 73%, 73.5%, 74%, 74.5% or 75%; or a range of any two of these values.
The pore-forming agent has a value ranging from 15% to 25%, namely, a minimum value and a maximum value ranging from 15% to 25%, and each value between the minimum value and the maximum value. Specific examples include, but are not limited to, the point values in the embodiments: 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, or 25%; or a range of any two of these values.
It can be understood that the purpose of adding the pore-forming agent is to form a pore structure, if the addition amount of the pore-forming agent is too large, the structural stability of the graphite composite material can be affected, and the mechanical property of the composite body can be reduced; if the addition amount of the pore-forming agent is too small, the pores are too small, which can affect the flow through efficiency of gas phase substances in the subsequent preparation of the silicon carbide material.
The range of the binder is 15% -30%, namely, the minimum value and the maximum value of the range of 15% -30% can be taken, and each value between the minimum value and the maximum value can be taken. Specific examples include, but are not limited to, the point values in the embodiments: 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5%, 34%, 34.5% or 35%; or a range of any two of these values.
It can be appreciated that the purpose of adding the polyamic acid binder is to facilitate the formation of the carbon-based aggregate under pressure, and if the binder is added in an excessive amount, the binder forms an excessively dense polyimide film, which affects the subsequent flow-through efficiency of the gas phase material in the preparation of the silicon carbide material; if the amount of the binder added is too small, the bonding cannot be performed, and the resulting graphite composite material is likely to be broken.
In some embodiments, the pore-forming agent comprises at least one of walnut powder, polyvinyl butyral (PVB), ammonium bicarbonate, sodium chloride, benzoic acid, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polystyrene (PS) microspheres, and polymethyl methacrylate (PMMA) microspheres.
In some embodiments, the carbon-based aggregate has a particle size of 50 μm to 300 μm.
By controlling the particle size of the carbon-based aggregate, the carbon-based aggregate can be easily molded under a certain pressure.
In some of these embodiments, the carbon-based aggregate comprises needle coke.
The application also provides a preparation method of the graphite composite material, which comprises the steps S10-S20.
Step S10: and mixing the preparation raw materials of the graphite composite material with a solvent to prepare mixed slurry.
In some embodiments, the solvent comprises at least one of N, N-dimethylacetamide, hexafluoroisopropanol, and dimethylsulfoxide.
Step S20: and (3) sequentially carrying out molding treatment, carbonization treatment and graphitization treatment on the mixed slurry to prepare the graphite composite material.
In some embodiments, the method further comprises drying the mixed slurry prior to the shaping process.
In some embodiments, the temperature of the drying process is 40 ℃ to 180 ℃.
It is to be understood that when a range of values is disclosed herein, the range is to be regarded as continuous, and includes both the minimum and maximum values for the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range description features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to include any and all subranges subsumed therein.
The temperature of the drying treatment is within the range of 40-180 ℃, namely, the minimum value and the maximum value of the range of 40-180 ℃ can be taken, and each value between the minimum value and the maximum value can be taken. Specific examples include, but are not limited to, the point values in the embodiments: 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, or 180 ℃; or a range of any two of these values.
In some embodiments, the drying time is 20min to 60min.
The range of the time of the drying treatment is 20-60 min, namely the minimum value and the maximum value of the range of 20-60 min can be taken, and each value between the minimum value and the maximum value. Specific examples include, but are not limited to, the point values in the embodiments: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 minutes; or a range of any two of these values.
In a specific example, the step of drying treatment includes a step a, a step b, and a step c.
Step a: and carrying out first drying treatment on the mixed slurry at 40-45 ℃ for 8-12 min to obtain first dried slurry.
Step b: and carrying out second drying treatment for 18-22 min at 50-55 ℃ on the first drying slurry to obtain second drying slurry.
Step c: and (3) carrying out third drying treatment for 18-22 min at 70-75 ℃ on the second dried slurry to obtain dried slurry, and carrying out subsequent forming treatment.
In some embodiments, the pressure of the molding treatment is 0.5mpa to 10mpa.
It should be noted that, the pressure of the molding process may have a value ranging from "0.5mpa to 10mpa", that is, a minimum value and a maximum value of the range from 0.5mpa to 10mpa, and each value between the minimum value and the maximum value. Specific examples include, but are not limited to, the point values in the embodiments: 0.5 A pressure of Mpa, 1Mpa, 1.5 Mpa, 2 Mpa, 2.5 Mpa, 3 Mpa, 3.5 Mpa, 4 Mpa, 4.5 Mpa, 5Mpa, 5.5 Mpa, 6 Mpa, 6.5 Mpa, 7 Mpa, 7.5 Mpa, 8 Mpa, 8.5 Mpa, 9 Mpa, 9.5 Mpa or 10Mpa; or a range of any two of these values.
In some embodiments, the temperature of the molding process is 260 ℃ to 300 ℃.
The temperature of the molding process is within the range of 260-300 ℃, namely, the minimum value and the maximum value of the range of 260-300 ℃ and each value between the minimum value and the maximum value can be taken. Specific examples include, but are not limited to, the point values in the embodiments: 260 ℃, 265 ℃, 270 ℃, 275 ℃, 280 ℃, 285 ℃, 290 ℃, 295 ℃ or 300 ℃; or a range of any two of these values.
In some embodiments, the molding process is performed for 20min to 90min.
The temperature of the molding treatment is within the range of 20-90 min, namely, the minimum value and the maximum value of the range of 20-90 min can be taken, and each value between the minimum value and the maximum value can be taken. Specific examples include, but are not limited to, the point values in the embodiments: 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90min; or a range of any two of these values.
In some embodiments, the step of carbonizing includes step a, step b, and step c.
Step a: and carrying out first roasting treatment on the slurry subjected to the forming treatment at the constant temperature of 300-400 ℃ for 10-15 hours to obtain first roasting slurry.
Step b: and carrying out second roasting treatment on the first roasting slurry for 20-30 hours at the constant temperature of 450-650 ℃ to obtain second roasting slurry.
Step c: and carrying out third roasting treatment on the second roasting slurry at the constant temperature of 700-1100 ℃ for 50-90 hours to obtain third roasting slurry, and carrying out graphitization treatment.
In some embodiments, the graphitization treatment temperature is 2000 ℃ to 2300 ℃.
The temperature of the graphitization treatment is in the range of 2000-2300 ℃, i.e., the minimum value and the maximum value of the range of 2000-2300 ℃ and each value between the minimum value and the maximum value are taken. Specific examples include, but are not limited to, the point values in the embodiments: 2000 ℃, 2050 ℃, 2100 ℃, 2150 ℃, 2200 ℃, 2250 ℃, 2300 ℃, 2350 ℃, 2400 ℃, 2450 ℃, 2500 ℃, 2550 ℃, 2600 ℃, 2650 ℃, 2700 ℃, 2750 ℃, 2800 ℃, 2850 ℃, 2900 ℃, 2950 ℃ or 2300 ℃; or a range of any two of these values.
In some embodiments, the graphitization treatment time is 20h to 70h.
The graphitization treatment time is in a value range of 20-70 h, namely, the minimum value and the maximum value of the range of 20-70 h can be taken, and each value between the minimum value and the maximum value is taken. Specific examples include, but are not limited to, the point values in the embodiments: 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h or 70h; or a range of any two of these values.
In some embodiments, after the step of carbonizing and before the step of graphitizing, the method further comprises the step of introducing inert gas to raise the temperature to 1700-1900 ℃, and introducing purified gas to perform purification treatment.
In some of these embodiments, the purified gas comprises at least one of freon, chlorine.
In a specific example, the purification treatment comprises introducing freon to purify for 2-7 h, heating to 2000-2300 ℃, introducing chlorine to purify for 7-9 h, and then vacuumizing and heating to 2000-2300 ℃ to carry out vacuum graphitization for 20-30 h.
It should be noted that the graphitization furnace used in the foregoing process may be performed by using a graphitization furnace commonly used in the art, for example: and a vacuum graphitization furnace device.
In some embodiments, the absolute vacuum is 50Pa to 150Pa.
The application also provides a preparation method of the silicon carbide material, which comprises the step of preparing the silicon carbide on the separator by adopting a gas phase transmission method, wherein the separator comprises the graphite composite material or the graphite composite material prepared by the preparation method of the graphite composite material.
It can be appreciated that the vapor phase transmission method is adopted to prepare the silicon carbide material on the separator, and the separator can maintain good mechanical properties in the growth of silicon carbide crystals, is not easy to pulverize, thereby reducing the occurrence probability of carbon inclusion.
The present application will be described in connection with specific embodiments, but is not limited thereto, and it is to be understood that the appended claims outline the scope of the application, and those skilled in the art, guided by the concepts herein provided, will recognize certain changes made to the embodiments of the application that will be covered by the spirit and scope of the claims of the application.
For the purpose of simplifying and clarifying the objects, technical solutions and advantages of the present application, the present application will be described with reference to the following specific examples, but the present application is by no means limited to these examples. The embodiments described below are only preferred embodiments of the present application and may be used to describe the present application and should not be construed as limiting the scope of the present application. It should be noted that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application are intended to be included in the scope of the present application.
Example 1
(1) Screening needle coke by a vibrating screen powder instrument, selecting needle coke with the size of 50 μm as aggregate, and uniformly mixing with polyamide acid, walnut powder and N, N-dimethylacetamide by a wet method and stirring for 30min to prepare mixed slurry, wherein the needle coke is 55wt%, the polyamide acid is 30wt% and the walnut powder is 15wt%.
(2) And (3) putting the uniformly stirred mixed slurry into a mould according to a certain weight, flattening, keeping the mould at a constant temperature of 40 ℃ for 10min, keeping the temperature of 50 ℃ for 20min, and keeping the temperature of 70 ℃ for 20min to volatilize the solvent to obtain the dried slurry.
(3) And (3) directly heating the dried slurry obtained in the step (2) to 280 ℃, and simultaneously applying pressure of 1MPa to the die for curing for 30min to mold the material, so as to obtain the molded slurry.
(4) Carbonizing the formed slurry obtained in the step (3), and roasting under the condition of isolating air; wherein, in the first stage, the temperature is raised for 2h to 250 ℃; in the second stage, the temperature is raised for 40h to 650 ℃; and in the third stage, heating to 750 ℃ for 6 hours, and keeping the temperature for 4 hours to obtain carbonized slurry.
(5) Graphitizing the carbonized slurry obtained in the step (4), wherein the carbonized slurry is prepared by the method comprising the steps of 2 Heating to 1900 ℃ from room temperature under protection, and introducing freon for purification for 3h; and heating to 2100 ℃, introducing chlorine gas, purifying for 8 hours, vacuumizing and heating to 2300 ℃ for vacuum graphitization for 20 hours, wherein the absolute vacuum degree of a vacuum graphitization furnace is 100Pa, and preparing the graphite composite material.
(6) The prepared graphite composite material was subjected to the following performance test.
1. The graphite composite materials prepared in the examples and the comparative examples were subjected to tensile strength performance test by using a universal mechanical instrument, specifically referring to ISO 527-2 standard.
2. The graphite composite materials prepared in the examples and the comparative examples were subjected to flexural strength performance test by using a universal mechanical instrument, with specific reference to the ISO 178 standard.
3. The graphite composites prepared in examples and comparative examples were subjected to a through-hole ratio test using a liquid saturation method, specifically referring to ASTM D737 standard.
4. And (3) analyzing the pore size of the graphite composite materials prepared in the examples and the comparative examples by utilizing a metallographic test, specifically preparing samples by adopting a cold mosaic mode, polishing the cold mosaic samples, and finally detecting and analyzing the plates by using a polarizing microscope.
Examples 2-6 were prepared in substantially the same manner as in example 1, except for the relevant parameters shown in table 1, wherein the specific parameters and the mixture ratios of the mixed slurries are shown in table 1 below.
Examples 7-9 were prepared in substantially the same manner as in example 1, except for the relevant parameters shown in table 2, wherein the specific parameters and the mixture ratios of the mixed slurries are shown in table 2 below.
Comparative examples 1-2 were prepared in substantially the same manner as in example 1 except for the parameters related to table 2, wherein the specific parameters and the mixture ratios of the mixed slurries are shown in table 2 below.
TABLE 1
TABLE 2
Note that: "/" indicates the absence of this component.
Fig. 1 is a diagram showing metallographic results of the graphite composite material prepared in example 1, and the tensile strength, the bending strength, the through hole ratio and the average pore size of the graphite composite materials in examples 1 to 9 and comparative examples 1 to 3 are shown in tables 1 to 2, and it can be seen that, compared with the graphite composite material prepared in comparative example, the graphite composite material prepared in the embodiment of the present application has higher tensile strength and bending strength and higher through hole ratio, and can maintain good mechanical properties in the growth of silicon carbide crystals, and is not easy to be pulverized, thereby reducing the occurrence probability of carbon wrappage.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims that follow.
Claims (10)
1. The graphite composite material is characterized by comprising the following preparation raw materials in percentage by mass: 55% -75% of carbon-based aggregate, 15% -25% of pore-forming agent and 15% -30% of binder, wherein the binder comprises polyamide acid.
2. The graphite composite material of claim 1, wherein the pore-forming agent comprises at least one of walnut powder, PVB, ammonium bicarbonate, sodium chloride, benzoic acid, PVP, PVA, PS microspheres, and PMMA microspheres.
3. The graphite composite material of claim 1, wherein the carbon-based aggregate has a particle size of 50 μm to 300 μm; and/or
The carbon-based aggregate includes needle coke.
4. The preparation method of the graphite composite material is characterized by comprising the following steps of:
mixing the preparation raw material of the graphite composite material according to any one of claims 1 to 3 with a solvent to prepare a mixed slurry;
and (3) sequentially carrying out forming treatment, carbonization treatment and graphitization treatment on the mixed slurry to prepare the graphite composite material.
5. The method of producing a graphite composite material as claimed in claim 4, further comprising, before said molding treatment, drying said mixed slurry, said drying treatment satisfying at least one of the following conditions (1) to (2):
(1) The temperature of the drying treatment is 40-180 ℃;
(2) The drying treatment time is 20-60 min.
6. The method of preparing a graphite composite material as recited in claim 5, wherein the step of drying comprises the steps of:
performing first drying treatment on the mixed slurry at 40-45 ℃ for 8-12 min to obtain first dried slurry;
performing second drying treatment for 18-22 min at 50-55 ℃ on the first dried slurry to obtain second dried slurry;
and carrying out third drying treatment for 18-22 min on the second drying slurry at 70-75 ℃.
7. The method for preparing a graphite composite material as claimed in any one of claims 4 to 6, wherein the molding treatment satisfies at least one condition of (1) to (3):
(1) The pressure of the molding treatment is 0.5 mpa-10 mpa;
(2) The temperature of the molding treatment is 260-300 ℃;
(3) The molding treatment time is 20-90 min.
8. The method for preparing a graphite composite material according to any one of claims 4 to 6, wherein the step of carbonizing treatment comprises the steps of:
carrying out first roasting treatment on the slurry subjected to the forming treatment at the constant temperature of 300-400 ℃ for 10-15 hours to obtain first roasting slurry;
performing second roasting treatment on the first roasting slurry at the constant temperature of 450-650 ℃ for 20-30 hours to obtain second roasting slurry;
and carrying out third roasting treatment on the second roasting slurry at the constant temperature of 700-1100 ℃ for 50-90 hours to obtain third roasting slurry, and carrying out graphitization treatment.
9. The method for preparing a graphite composite material according to any one of claims 4 to 6, wherein the graphitization treatment satisfies at least one of the conditions (1) to (3):
(1) The graphitization treatment temperature is 2000-2300 ℃;
(2) The graphitization treatment time is 20-70 h;
(3) After the step of carbonizing and before the step of graphitizing, the method further comprises the steps of:
introducing inert gas to raise the temperature to 1700-1900 ℃, and introducing purified gas to carry out purification treatment;
optionally, the purified gas comprises at least one of freon and chlorine.
10. The preparation method of the silicon carbide material is characterized by comprising the following steps of:
preparing silicon carbide on the partition board by adopting a gas phase transmission method;
the separator comprises a graphite composite material according to any one of claims 1 to 3 or a graphite composite material produced by the method for producing a graphite composite material according to any one of claims 4 to 9.
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