CN109133923B - Method for preparing special graphite paper from graphene oxide-special graphite powder - Google Patents
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- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
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Abstract
The invention discloses a method for preparing special graphite paper by using oxidized graphene-special graphite powder, which is a product obtained by milling, powder mixing, acid washing, intercalation, water washing, expansion, primary sintering, secondary sintering and rolling of oxidized graphene powder, special graphite powder, carbon black and graphite flakes, wherein the carbon content of the product is more than or equal to 99.9%, the thickness is less than or equal to 150 mu m, the tensile strength is more than or equal to 4.5MPa, and the thermal conductivity is more than or equal to 800W/(m.K). The invention has simple and convenient process, stable performance of the finished product, good heat conductivity and electrical conductivity and excellent comprehensive physical and chemical indexes.
Description
Technical Field
The invention relates to a graphite material, in particular to a method for preparing special graphite paper from graphene oxide-special graphite powder.
Background
Graphite paper is the basic material for making various electronic and graphite seals. The sealing material is widely applied to dynamic sealing and static sealing of machines, pipes, pumps and valves in the industries of notebook computers, flat panel displays, digital cameras, mobile phones, electric power, petroleum, chemical engineering, instruments, machinery, diamond and the like, and is an ideal novel sealing material for replacing traditional sealing elements such as rubber, fluoroplastic, asbestos and the like.
With the acceleration of upgrading and upgrading of electronic products and the increasing heat dissipation management requirements of mini, highly integrated and high-performance electronic equipment, a brand new electronic product heat dissipation technology, namely a new graphite material heat dissipation solution, is also provided.
The graphite paper has high heat dissipation efficiency, small occupied space and light weight, and can uniformly conduct heat along two directions, eliminate 'hot spot' areas, shield heat sources and components and improve the performance of consumer electronic products.
At present, graphite paper is widely used, but the production process of each manufacturer is basically secret or protected by patents, so that the applicant cannot produce and research.
Disclosure of Invention
In view of the above defects in the prior art, the technical problem to be solved by the present invention is to provide a method for preparing special graphite paper from graphene oxide-special graphite powder, wherein the method has characteristics of simple process and stable finished product performance.
In order to achieve the purpose, the invention provides a method for preparing special graphite paper from graphene oxide-special graphite powder, which comprises the following steps:
s1, raw materials, powder materials and mixed materials;
the powder material is graphene oxide powder, special graphite powder, carbon black and graphite flakes;
the purity of the graphene oxide powder is 99.9%, and the particle size is 400 meshes.
The volume density of the special graphite powder is 1.80g/cm3, the resistivity is less than or equal to 8 mu omega m, the breaking strength is greater than or equal to 30Mpa, the compressive strength is greater than or equal to 60Mpa, and the particle size is 450 meshes;
the purity of the powder carbon black is 99%, and the particle size is 500 meshes;
the purity of the powder graphite flake is 99%, and the particle size is 550 meshes;
the mixed powder comprises the following components in parts by weight: the graphene oxide powder, the special graphite powder, the carbon black and the graphite flakes are in a weight ratio of 10:30:20:40 to 15:25:15:45 (the weight percentage of each component can be converted to obtain a definite interval value);
s2, grinding, namely grinding the powder material in the S1 by a ball mill respectively for 10-20h at the speed of 500-800r/min, and sieving the powder material with a sieve to screen the powder material;
s3, mixing powder, namely uniformly mixing the powder according to the proportion in the S1, wherein the mixing usually adopts a wet mixing mechanical method, namely the powder is mixed in a mixer by taking liquid as a medium. The liquid medium is ethanol.
S4, acid washing, namely mixing the mixed powder with a concentrated sulfuric acid solution to obtain an acid washing substance, wherein the mass ratio of the mixed powder to the concentrated sulfuric acid solution is 1:3-5, and the mass fraction of concentrated sulfuric acid in the concentrated sulfuric acid solution is 95% -98%; the mixing time is 20min to 30min, and the temperature of the oxidation reaction is room temperature;
and S5, intercalation, namely adding an oxidant into the acid-washed matter of S4 for oxidation intercalation reaction to form an oxidation intercalation matter. Wherein the oxidant is a nitric acid solution, the mass ratio of the acid washing substance to the nitric acid solution is 1: 3-1: 8, and the mass fraction of nitric acid in the nitric acid solution is 50% -70%; the time is 70 min-100 min, and the temperature of intercalation reaction is less than 70 ℃;
s6, washing with water, namely washing the S5 oxidized intercalation with water until the pH value is 6-7;
and S7, swelling, and preparing the S6 water-washed substance by using a graphite swelling furnace under inert gas.
Firstly, feeding, namely feeding into a hearth through a feeding hole, wherein the temperature of the feeding hole is room temperature;
secondly, expanding, wherein the expansion temperature of the hearth is 700-1000 ℃;
and finally, discharging, wherein the temperature of a discharge hole is 50 ℃, and then collecting the expanded graphite material at the discharge hole, wherein the temperature is controlled to be +/-5 ℃. The inert gas is a mixed gas of nitrogen and argon, and the volume ratio of the nitrogen to the argon is 95: 5-90: 10.
S8, primary sintering, wherein the molding material is sintered at the temperature of 800-1000 ℃ under the condition of introducing argon to prevent the molding material from being oxidized, the sintering heat preservation and pressurization time is 15-20min, and the sintering pressure is 50-100 MPa;
s9, sintering again, and adopting a spark plasma sintering process at the highest temperature of 2500 ℃ to obtain the special graphite paper material;
and S10, rolling, namely rolling the special graphite material into a paper material by a rolling machine for 5-10 times. The carbon content (%) of the special graphite paper is more than or equal to 99.9, the thickness mu m is less than or equal to 150, the tensile strength MPa is more than or equal to 4.5, and the thermal conductivity W/(m.K) is more than or equal to 800.
The invention has the beneficial effects that: the invention has simple and convenient process, stable performance of the finished product, good heat conductivity and electrical conductivity and excellent comprehensive physical and chemical indexes.
Detailed Description
The invention is further illustrated by the following examples:
according to the invention, through detailed research on raw materials, ingredients and a preparation process, the carbon content (%) of a finished product is more than or equal to 99.9, the thickness mu m is less than or equal to 150, the tensile strength MPa is more than or equal to 4.5, and the thermal conductivity W/(m.K) is more than or equal to 800.
Through multiple experiments, research analysis and product trial production, the inventor selects graphene oxide powder with the purity of 99.9 percent and the particle size of 400 meshes from the raw material selection; the volume density is 1.80g/cm3, the resistivity is less than or equal to 8 mu omega m, the flexural strength is more than or equal to 30MPa, the compressive strength is more than or equal to 65MPa, the ash content is less than or equal to 0.30 percent, and the particle size is 450 meshes; the purity is 99 percent, and the particle size is 500 meshes; the purity is 99 percent, and the graphite flake with the grain diameter of 550 meshes is powder.
The ingredients are graphene oxide powder, special graphite powder, carbon black and graphite flakes which are mixed according to the weight ratio of 10:30:20:40 to 15:25:15: 45.
And grinding, powder mixing, acid washing, intercalation, water washing, expansion, primary sintering, secondary sintering and rolling to obtain the product.
The grinding is to grind the powder by a ball mill respectively, wherein the grinding time is 15h, the speed is 700r/min, and the powder is sieved and sieved.
The powder mixing is a process of uniformly mixing the powder materials according to the proportion, and the mixing usually adopts a wet mixing mechanical method, namely the powder materials are mixed in a mixer by taking liquid as a medium. The liquid medium is ethanol.
The acid washing is to mix mixed powder and concentrated sulfuric acid solution to obtain acid washing matters, wherein the mass ratio of the mixed powder to the concentrated sulfuric acid solution is 1:4, and the mass fraction of concentrated sulfuric acid in the concentrated sulfuric acid solution is 95-98%; the mixing time was 25min and the temperature of the oxidation reaction was room temperature.
The intercalation is to add oxidant into the acid washing matter to carry out oxidation intercalation reaction to form oxidation intercalation matter. Wherein the oxidant is a nitric acid solution, the mass ratio of the acid washing substance to the nitric acid solution is 1:6, and the mass fraction of nitric acid in the nitric acid solution is 60%; the time is 80min, and the temperature of intercalation reaction is less than 70 ℃.
The water washing is to wash the oxidized intercalation to pH 6-7.
The expansion is carried out by preparing the water washing material by a graphite expansion furnace under inert gas. Firstly, feeding, namely feeding into a hearth through a feeding hole, wherein the temperature of the feeding hole is room temperature; secondly, expanding, wherein the expansion temperature of the hearth is 900 ℃; and finally, discharging, wherein the temperature of a discharge hole is 50 ℃, and then collecting at the discharge hole to obtain the expanded graphite material. The temperature is controlled at +/-5 ℃. The inert gas is a mixed gas of nitrogen and argon, and the volume ratio of the nitrogen to the argon is 95: 5-90: 10.
The one-step sintering is carried out on the premise that the formed material is introduced with argon to prevent the formed material from being oxidized, the temperature is 900 ℃, the sintering heat preservation and pressurization time is 20min, and the sintering pressure is 60 MPa.
The secondary sintering is to adopt a spark plasma sintering process, the highest temperature is 2500 ℃, and the special graphite paper material is obtained.
The rolling is to roll the special graphite material into paper-like material by a rolling machine for 8 times. The material has good thermal conductivity and electrical conductivity and excellent comprehensive physical and chemical indexes.
The invention is not described in detail, but is well known to those skilled in the art.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (4)
1. A method for preparing special graphite paper from graphene oxide-special graphite powder is characterized by comprising the following steps:
s1, raw materials, powder materials and mixed materials; the powder material is graphene oxide powder, special graphite powder, carbon black and graphite flakes;
the mixed powder comprises the following components in parts by weight: the graphite comprises graphene oxide powder, special graphite powder, carbon black and graphite flakes, wherein the weight ratio of the graphene oxide powder to the special graphite powder to the carbon black to the graphite flakes is 10:30:20:40 to 15:25:15: 45;
the purity of the graphene oxide powder is 99.9%, and the particle size is 400 meshes;
the volume density of the special graphite powder is 1.80g/cm3, the resistivity is less than or equal to 8 mu omega m, the breaking strength is greater than or equal to 30Mpa, the compressive strength is greater than or equal to 60Mpa, and the particle size is 450 meshes;
the purity of the powder carbon black is 99%, and the particle size is 500 meshes;
the purity of the powder graphite flake is 99%, and the particle size is 550 meshes;
s2, grinding, namely grinding the powder material in the S1 by a ball mill respectively for 10-20h at the speed of 500-800r/min, and sieving the powder material with a sieve to screen the powder material;
s3, mixing powder, namely uniformly mixing the powder according to the proportion in the S1;
s4, acid washing, namely mixing the mixed powder with a concentrated sulfuric acid solution to obtain an acid washing substance;
the mass ratio of the mixed powder to the concentrated sulfuric acid solution is 1: 3-5;
the mass fraction of concentrated sulfuric acid in the concentrated sulfuric acid solution is 95-98%;
the mixing time is 20min to 30min, and the temperature of the oxidation reaction is room temperature;
s5, intercalation, namely adding an oxidant into the acid-washed matter of S4 to carry out oxidation intercalation reaction to form an oxidation intercalation matter;
the oxidant is a nitric acid solution, the mass ratio of the acid washing substance to the nitric acid solution is 1: 3-1: 8, and the mass fraction of nitric acid in the nitric acid solution is 50% -70%; the time is 70 min-100 min, and the temperature of intercalation reaction is less than 70 ℃;
s6, washing with water, namely washing the S5 oxidized intercalation with water until the pH value is 6-7;
s7, swelling, namely preparing the S6 water-washed substance by using a graphite swelling furnace under inert gas, and comprising the following steps:
firstly, feeding, namely feeding into a hearth through a feeding hole, wherein the temperature of the feeding hole is room temperature;
secondly, expanding, wherein the expansion temperature of the hearth is 700-1000 ℃;
finally, discharging, wherein the temperature of a discharge port is 50 ℃, and then collecting the expanded graphite material at the discharge port, wherein the temperature is controlled to be +/-5 ℃;
s8, primary sintering, wherein the molding material is sintered at the temperature of 800-1000 ℃ under the condition of introducing argon to prevent the molding material from being oxidized, the sintering heat preservation and pressurization time is 15-20min, and the sintering pressure is 50-100 MPa;
s9, sintering again, and adopting a spark plasma sintering process at the highest temperature of 2500 ℃ to obtain the special graphite paper material;
s10, rolling, namely rolling the special graphite material into a paper-like material for 5-10 times by using a rolling machine to obtain the special graphite paper, wherein the carbon content of the special graphite paper is more than or equal to 99.9%, the thickness of the special graphite paper is less than or equal to 150 mu m, the tensile strength of the special graphite paper is more than or equal to 4.5MPa, and the thermal conductivity of the special graphite paper is more than or equal to 800W/(m.K).
2. The method of claim 1, wherein in S3, wet mixing mechanical method is adopted, that is, powder is mixed in a mixer by taking liquid as a medium.
3. The method of claim 2, wherein the medium is ethanol.
4. The method according to claim 1, wherein in S7, the inert gas is a mixed gas of nitrogen and argon, and the volume ratio of the nitrogen to the argon is 95: 5-90: 10.
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| CN111204754B (en) * | 2020-01-14 | 2021-11-09 | 大同新成新材料股份有限公司 | Preparation method of graphene oxide silicon-carbon composite negative electrode material |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09324390A (en) * | 1996-06-07 | 1997-12-16 | Toray Ind Inc | Carbon fiber paper and porous carbon board |
| CN103700513A (en) * | 2013-12-30 | 2014-04-02 | 中山大学 | Graphene paper and preparation method and application thereof |
| CN104003380A (en) * | 2014-06-09 | 2014-08-27 | 黑龙江奥星能源科技有限公司 | Preparation method of ultra-thin graphite paper and graphene oxide composited film |
| CN108190882A (en) * | 2018-02-26 | 2018-06-22 | 乌兰察布市大盛石墨新材料股份有限公司 | Conductive graphite paper and preparation method thereof |
| CN108373152A (en) * | 2018-02-26 | 2018-08-07 | 乌兰察布市大盛石墨新材料股份有限公司 | Conductive graphite paper and preparation method thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09324390A (en) * | 1996-06-07 | 1997-12-16 | Toray Ind Inc | Carbon fiber paper and porous carbon board |
| CN103700513A (en) * | 2013-12-30 | 2014-04-02 | 中山大学 | Graphene paper and preparation method and application thereof |
| CN104003380A (en) * | 2014-06-09 | 2014-08-27 | 黑龙江奥星能源科技有限公司 | Preparation method of ultra-thin graphite paper and graphene oxide composited film |
| CN108190882A (en) * | 2018-02-26 | 2018-06-22 | 乌兰察布市大盛石墨新材料股份有限公司 | Conductive graphite paper and preparation method thereof |
| CN108373152A (en) * | 2018-02-26 | 2018-08-07 | 乌兰察布市大盛石墨新材料股份有限公司 | Conductive graphite paper and preparation method thereof |
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