CN114716229A - Silicon carbide aerogel and preparation method thereof - Google Patents
Silicon carbide aerogel and preparation method thereof Download PDFInfo
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 96
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 96
- 239000004964 aerogel Substances 0.000 title claims abstract description 70
- 238000002360 preparation method Methods 0.000 title abstract description 15
- 239000000835 fiber Substances 0.000 claims abstract description 20
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 69
- 239000004917 carbon fiber Substances 0.000 claims description 69
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 66
- 229910052710 silicon Inorganic materials 0.000 claims description 66
- 239000010703 silicon Substances 0.000 claims description 66
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 45
- 238000005245 sintering Methods 0.000 claims description 33
- 229910052799 carbon Inorganic materials 0.000 claims description 31
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 30
- 238000001035 drying Methods 0.000 claims description 26
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 24
- 239000007789 gas Substances 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 20
- 239000002131 composite material Substances 0.000 claims description 19
- 230000003301 hydrolyzing effect Effects 0.000 claims description 14
- 239000003795 chemical substances by application Substances 0.000 claims description 12
- 239000011261 inert gas Substances 0.000 claims description 10
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 10
- 238000002791 soaking Methods 0.000 claims description 10
- UQEAIHBTYFGYIE-UHFFFAOYSA-N hexamethyldisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)C UQEAIHBTYFGYIE-UHFFFAOYSA-N 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 239000012298 atmosphere Substances 0.000 claims description 6
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 claims description 5
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 239000008367 deionised water Substances 0.000 claims description 3
- 229910021641 deionized water Inorganic materials 0.000 claims description 3
- JJQZDUKDJDQPMQ-UHFFFAOYSA-N dimethoxy(dimethyl)silane Chemical compound CO[Si](C)(C)OC JJQZDUKDJDQPMQ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000009413 insulation Methods 0.000 abstract description 12
- 238000013461 design Methods 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 19
- 239000010410 layer Substances 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 13
- 238000010438 heat treatment Methods 0.000 description 12
- 239000002356 single layer Substances 0.000 description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 238000004321 preservation Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 239000012300 argon atmosphere Substances 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000010030 laminating Methods 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 239000011148 porous material Substances 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 238000013112 stability test Methods 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002070 nanowire Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 238000012512 characterization method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000009661 fatigue test Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- 239000000843 powder Substances 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 238000002679 ablation Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920003257 polycarbosilane Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
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Abstract
The invention provides a silicon carbide aerogel and a preparation method thereof, wherein the silicon carbide aerogel comprises at least two silicon carbide fiber layers which are stacked, and a gap is formed between every two adjacent silicon carbide fiber layers; each silicon carbide fiber layer comprises a plurality of silicon carbide fibers, and the silicon carbide fibers are mutually crosslinked to form a plurality of holes. According to the silicon carbide aerogel provided by the invention, the gap structure among the layers can buffer external impact, so that the elasticity of the silicon carbide aerogel is enhanced, meanwhile, the integral heat insulation is improved by the porous structure, the reasonable design of the integral structure ensures good mechanical property and strong heat insulation.
Description
Technical Field
The invention belongs to the field of materials, and particularly relates to a silicon carbide aerogel and a preparation method thereof.
Background
The silicon carbide aerogel has the excellent characteristics of high temperature resistance, strong chemical stability, high porosity, low density and the like. Therefore, the silicon carbide aerogel is a high-temperature-resistant heat-insulating material with great application potential.
Currently, the preparation of silicon carbide aerogel mainly comprises the following two methods. The first method mainly utilizes the pyrolysis and rearrangement of polycarbosilane at high temperature to prepare silicon carbide aerogel, such as Chinese patents CN111484018A and CN 112537964A. The internal pore structure of the silicon carbide aerogel obtained by the preparation method is randomly formed, and the obtained silicon carbide aerogel has low porosity and high density, so that the thermal conductivity coefficient is relatively high (> 0.04W/mK). The other method is to mix a silicon source and a carbon source to prepare a preform, and then perform high-temperature sintering in an inert environment to obtain the silicon carbide aerogel. The method can effectively improve the porosity of the silicon carbide aerogel and further reduce the density and the heat conductivity coefficient, but the silicon carbide aerogel obtained by the method has poor mechanical property and brittleness, and is not beneficial to practical application. In summary, the problems of high thermal conductivity and poor mechanical properties of the obtained aerogel still exist in the existing preparation method of the silicon carbide aerogel.
Disclosure of Invention
In view of the above, the present invention provides a silicon carbide aerogel and a preparation method thereof, and aims to provide a silicon carbide aerogel with excellent thermal insulation property and mechanical property.
In order to achieve the above object, the present invention provides a silicon carbide aerogel, which comprises at least two silicon carbide fiber layers stacked together, wherein a gap is formed between two adjacent silicon carbide fiber layers; each silicon carbide fiber layer comprises a plurality of silicon carbide fibers, and the silicon carbide fibers are mutually crosslinked to form a plurality of holes.
In addition, the invention also provides a preparation method of the silicon carbide aerogel, which comprises the following steps:
assembling a plurality of layers of carbon fiber felts into a carbon source body;
soaking the carbon source body in a first solution to obtain a silicon source attachment, wherein the first solution comprises a silicon source and a hydrolyzing agent, and the hydrolyzing agent hydrolyzes the silicon source;
drying the silicon source attachment to obtain a silicon source-carbon fiber compound;
and sintering the silicon source-carbon fiber composite in an inert gas atmosphere to obtain the silicon carbide aerogel.
Optionally, in the step of assembling the carbon fiber felt into the carbon source body, the density of the carbon fiber felt is 0.05-0.15 g/cm3(ii) a And/or the presence of a gas in the gas,
the thickness of each carbon fiber felt is 0.2-5 mm.
Optionally, the silicon source comprises at least one of methyltrimethoxysilane, dimethyldimethoxysilane, and hexamethyldisiloxane; and/or the presence of a gas in the gas,
the hydrolytic agent comprises at least one of deionized water, ethanol and tertiary butanol; and/or the presence of a gas in the gas,
the mass ratio of the silicon source to the hydrolytic agent is (0.1-1): 1.
optionally, in the step of drying the silicon source attachment to obtain the silicon source-carbon fiber composite, the drying temperature is 100-150 ℃; and/or the presence of a gas in the gas,
the drying time is 2-10 h.
Optionally, in the step of sintering the silicon source-carbon fiber composite in an inert gas atmosphere to obtain the silicon carbide aerogel, the sintering temperature is 1300 ℃ to 1700 ℃; and/or the presence of a gas in the gas,
the inert gas comprises at least one of argon and nitrogen; and/or the presence of a gas in the gas,
the sintering time is 0.5-3 h.
Optionally, the sintering is sequentially performed through a temperature rise stage and a heat preservation stage, wherein in the temperature rise stage, the temperature is raised to the sintering temperature at a speed of 3-10 ℃/min, and in the heat preservation stage, the sintering temperature is maintained for 0.5-3 h.
Optionally, before the step of assembling the plurality of layers of carbon fiber mats into the carbon source body, the method further comprises:
providing a carbon fiber body and separating the carbon fiber body into a plurality of layers of carbon fiber felts.
According to the silicon carbide aerogel provided by the invention, the gap structure between layers can buffer external impact, so that the elasticity of the silicon carbide aerogel is enhanced, and meanwhile, the overall heat insulation property is improved due to the porous structure; the reasonable design of the whole structure ensures good mechanical property and strong heat insulation property.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a cross-sectional view of a silicon carbide aerogel according to example 1;
FIG. 3 is an enlarged view of the internal structure of the silicon carbide aerogel according to example 1;
FIG. 4 is a thermal conductivity test curve for the silicon carbide gel of example 1;
FIG. 5 is a graph showing temperature measurements of a silicon carbide gel in accordance with example 1 under high-temperature treatment;
FIG. 6 shows the results of mechanical property tests of the silicon carbide gel of example 1;
FIG. 7 shows the results of the thermal stability test of the silicon carbide gel of example 1.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be apparent that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments.
It should be noted that those whose specific conditions are not specified in the examples were performed according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are conventional products which are not indicated by manufacturers and are commercially available. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In view of the technical problems of poor heat insulation performance and poor mechanical property of the existing silicon carbide aerogel, the invention provides the silicon carbide aerogel, which comprises at least two silicon carbide fiber layers which are stacked, and a gap is formed between every two adjacent silicon carbide fiber layers; each silicon carbide fiber layer comprises a plurality of silicon carbide fibers, and the silicon carbide fibers are mutually crosslinked to form a plurality of holes.
According to the silicon carbide aerogel provided by the invention, the gap structure between layers can buffer external impact, so that the elasticity of the silicon carbide aerogel is enhanced, and meanwhile, the overall heat insulation property is improved due to the porous structure; the reasonable design of the whole structure ensures good mechanical property and strong heat insulation property.
In addition, as shown in fig. 1, the present invention also provides a method for preparing the above silicon carbide aerogel, which comprises the following steps:
step S10: assembling a plurality of layers of carbon fiber felts into a carbon source body;
step S20: soaking the carbon source body in a first solution to obtain a silicon source attachment, wherein the first solution comprises a silicon source and a hydrolyzing agent, and the hydrolyzing agent hydrolyzes the silicon source;
step S30: drying the silicon source attachment to obtain a silicon source-carbon fiber compound;
step S40: and sintering the silicon source-carbon fiber composite in an inert gas atmosphere to obtain the silicon carbide aerogel.
By adopting the steps, the silicon carbide aerogel which is laminated layer by layer and has a porous structure can be prepared, and the good mechanical property and the strong heat insulation property of the silicon carbide aerogel are ensured.
It should be noted that the carbon fiber mat may have a density and a thickness equal to each otherAccording to the requirement, in some embodiments, in the step S10, the density of the carbon fiber felt is 0.05-0.15 g/cm3The density is in this range, the performance is optimum, e.g. less than 0.05g/cm3This may result in an excessively low density and a low strength, e.g., greater than 0.15g/cm3The void structure is reduced, affecting the thermal insulation performance. In some embodiments, each of the carbon fiber mats may have a thickness of 0.2 to 5 mm.
In step S20, the silicon source reacts with the hydrolytic reagent to generate short-chain silica, and for this purpose, the types of the silicon source and the hydrolytic reagent may not be limited, for example, the silicon source includes at least one of methyltrimethoxysilane, dimethyldimethoxysilane, hexamethyldisiloxane and silicon monoxide; the hydrolyzing agent comprises at least one of deionized water, ethanol and tertiary butanol.
Further, in some embodiments, the mass ratio of the silicon source to the hydrolytic agent is (0.1-1): 1. the silicon carbide aerogel generated by the reaction at the ratio has the best comprehensive performance, and when the ratio is less than 0.1, a silicon source is too little, so that sufficient silicon dioxide is difficult to generate and react with carbon fibers, the generation of silicon carbide is further influenced, and the heat insulation property and the mechanical property are reduced; when the ratio is more than 1:1, the degree of hydrolysis is insufficient, and sufficient silica cannot be supplied, so that the reaction is hindered. Moreover, if not at this ratio, the incompletely hydrolyzed byproducts tend to form localized deposits and crystallize at high temperatures, ultimately reducing the aerogel thermal conductivity.
In step S30, the drying removes the solvent and further ages the silica produced; in some implementations, the temperature of the drying is 100 to 150 ℃; and drying for 2-10 h. The drying parameters are controlled according to the above, so that the drying effect can be further ensured.
In step S40, the sintering temperature is 1300-1700 ℃; when the sintering temperature is controlled within the above range, not only the carbon fibers and the silicon source can be reacted to produce silicon carbide, but also components such as a binder on the carbon fiber mat can be removed.
It should be noted that, sintering is performed under an inert gas atmosphere, so that a reaction between a carbon source and oxygen in air can be avoided, and a reaction effect is not affected, and the inert gas can be selected based on any conditions, and in some embodiments, the inert gas includes at least one of argon and nitrogen; in step S40, the sintering time is 0.5 to 3 hours, and the energy consumption can be controlled by controlling the reaction time within the above range to ensure the completion of the reaction. If the sintering time is less than 0.5h, the reaction is incomplete, and if it is more than 3h, the energy consumption is too large.
It should be noted that, under the condition of satisfying the sintering condition, the sintering procedure may be selected according to the actual situation of the production, and in some embodiments, the sintering procedure is selected to have the highest applicability with the existing sintering equipment, for example, the sintering is sequentially performed through a temperature rising stage and a temperature holding stage, wherein, in the temperature rising stage, the temperature is raised to the sintering temperature at 3-10 ℃/min, and in the temperature holding stage, the sintering temperature is maintained for 0.5-3 h.
In some embodiments, before step S10, the method further includes: providing a carbon fiber body and separating the carbon fiber body into a plurality of layers of carbon fiber felts. The carbon fiber felt is obtained through separation, the thickness can be freely controlled, and product diversification is realized.
The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, it should be understood that the following examples are merely illustrative of the present invention and are not intended to limit the present invention.
The carbon fiber felt is purchased from North sea carbon Co., Ltd, and has the model number of SMZ3 MM.
Example 1
The embodiment provides a preparation method of silicon carbide aerogel, which specifically comprises the following operations:
taking a 20g block with side length of 10cm and density of 0.08g/cm3The carbon fiber felt of (4) was mechanically peeled to form a single-layer carbon fiber felt of 0.5 mm. And then laminating the obtained single-layer carbon fiber felt mat and extruding to form a carbon source body. Taking 100g of methyltrimethoxysilane and 200g of ethanol, mixing and uniformly stirring the two to obtain a silicon source solution, and then soaking a carbon source in the silicon source solution. Then soaking the carbon source body with the silicon source solutionAnd (3) drying the mixture in a drying oven at 100 ℃ for 2 hours to obtain the silicon source-carbon fiber composite. Heating the silicon source-carbon fiber composite to 1400 ℃ at the heating rate of 5 ℃/min in the argon atmosphere, and then carrying out heat preservation sintering for 2h to obtain the silicon carbide aerogel material.
Example 2
The embodiment provides a preparation method of silicon carbide aerogel, which specifically comprises the following operations:
taking a 20g block with side length of 10cm and density of 0.08g/cm3The carbon fiber felt of (4) was mechanically peeled to form a single-layer carbon fiber felt of 0.5 mm. And then laminating the obtained single-layer carbon fiber felt mat and extruding to form a carbon source body. Taking 100g of SiO powder and 200g of ethanol, mixing and uniformly stirring the SiO powder and the ethanol to obtain a silicon source solution, and then putting a carbon source body in the silicon source solution. And then putting the carbon source body soaked with the silicon source solution into a drying oven at 100 ℃ for drying for 2 hours to obtain the silicon source-carbon fiber composite. Heating the silicon source-carbon fiber composite to 1400 ℃ at the heating rate of 5 ℃/min in the argon atmosphere, and then carrying out heat preservation sintering for 2h to obtain the silicon carbide aerogel material.
Example 3
The embodiment provides a preparation method of silicon carbide aerogel, which specifically comprises the following operations:
taking a 20g block with side length of 10cm and density of 0.08g/cm3The carbon fiber felt of (4) was mechanically peeled to form a single-layer carbon fiber felt of 0.5 mm. And then laminating the obtained single-layer carbon fiber felt mat and extruding to form a carbon source body. And (2) taking 100g of hexamethyldisiloxane and 200g of ethanol, mixing and uniformly stirring the hexamethyldisiloxane and the ethanol to obtain a silicon source solution, and then soaking a carbon source in the silicon source solution. And then, putting the carbon source body soaked with the silicon source solution into a drying oven at 100 ℃ for drying for 2 hours to obtain the silicon source-carbon fiber composite. Heating the silicon source-carbon fiber composite to 1400 ℃ at the heating rate of 5 ℃/min in the argon atmosphere, and then carrying out heat preservation sintering for 2h to obtain the low-heat-conductivity high-elasticity silicon carbide aerogel material with the sandwich structure.
Example 4
The embodiment provides a preparation method of silicon carbide aerogel, which specifically comprises the following operations:
taking a block of 20g with side length of 10cm and density of 0.15g/cm3The carbon fiber felt of (4) was mechanically peeled to form a single-layer carbon fiber felt of 5 mm. And then laminating the obtained single-layer carbon fiber felt mat and extruding to form a carbon source body. Taking 100g of methyltrimethoxysilane and 1000g of ethanol, mixing and uniformly stirring the two to obtain a silicon source solution, and then soaking a carbon source in the silicon source solution. And then, putting the carbon source body soaked with the silicon source solution into a drying oven at 150 ℃ for drying for 3 hours to obtain the silicon source-carbon fiber composite. Heating the silicon source-carbon fiber composite to 1700 ℃ at the heating rate of 5 ℃/min in the argon atmosphere, and then carrying out heat preservation sintering for 3h to obtain the silicon carbide aerogel material.
Example 5
The embodiment provides a preparation method of silicon carbide aerogel, which specifically comprises the following operations:
taking a block of 20g with side length of 10cm and density of 0.05g/cm3The carbon fiber felt of (4) was mechanically peeled to form a single-layer carbon fiber felt of 5 mm. And then laminating the obtained single-layer carbon fiber felt mat and extruding to form a carbon source body. And (2) taking 100g of hexamethyldisiloxane and 100g of ethanol, mixing and uniformly stirring the hexamethyldisiloxane and the ethanol to obtain a silicon source solution, and then soaking a carbon source in the silicon source solution. And then, putting the carbon source body soaked with the silicon source solution into a drying oven at 110 ℃ for drying for 10 hours to obtain the silicon source-carbon fiber composite. Heating the silicon source-carbon fiber composite to 1700 ℃ at the heating rate of 5 ℃/min in the argon atmosphere, and then carrying out heat preservation sintering for 0.5h to obtain the low-heat-conductivity high-elasticity silicon carbide aerogel material with the sandwich structure.
Example 6
The embodiment provides a preparation method of silicon carbide aerogel, which specifically comprises the following operations:
taking a block of 20g with side length of 10cm and density of 0.12g/cm3The carbon fiber felt of (4) was mechanically peeled to form a single-layer carbon fiber felt of 5 mm. And then laminating the obtained single-layer carbon fiber felt mat and extruding to form a carbon source body. And mixing 80g of SiO and 100g of ethanol, uniformly stirring to obtain a silicon source solution, and soaking the carbon source in the silicon source solution. Then soaking the carbon source body with the silicon source solutionAnd (3) drying the mixture in a drying oven at 100 ℃ for 10 hours to obtain the silicon source-carbon fiber composite. Heating the silicon source-carbon fiber composite to 1300 ℃ at the heating rate of 5 ℃/min in the argon atmosphere, and then carrying out heat preservation sintering for 3h to obtain the silicon carbide aerogel material.
Comparative example 1
This comparative example provides a method of preparing a silicon carbide aerogel, the specific operation being substantially identical to that of example 1, except that the carbon fiber mat was not cut and the whole was immersed in a silicon source solution.
Test examples
In the test example, the silicon carbide prepared in examples 1 to 6 and comparative example 1 was subjected to performance testing, and the testing items and method were as follows:
(1) and (3) microstructure characterization:
the integral structure and the microstructure are obtained through electron microscope characterization, the characterized integral structure shows that the obtained aerogel has an obvious laminated layer, each layer of the inner part is formed by staggered arrangement of silicon carbide nanowires, and the silicon carbide nanowires are crosslinked to form rich pores.
Wherein, the section view of the silicon carbide aerogel of example 1 is shown in fig. 2, a is a gap formed between adjacent layers; fig. 3 is an enlarged picture of the internal structure, in fig. 3, a is a whole structure diagram, a clear laminated structure can be seen from the drawing, b is an enlarged view of a position 1 in a, silicon carbide nanowires can be seen to be staggered and form abundant pores, c is an enlarged view of a position 2 in b, and the structure of the staggered pores can be clearly seen through further enlargement.
(2) The heat conductivity coefficient test method comprises the following steps: and when the temperature is in the range of room temperature to 500 ℃, performing heat conductivity test on the prepared aerogel by using a Hot Disc heat conductivity coefficient instrument, performing three repeated tests on each sample, and averaging. And when the temperature is higher than 500 ℃, testing by using a laser thermal conductivity meter, and repeatedly testing each sample for three times and taking an average value. The test results are shown in table 1, wherein the thermal conductivity of the silicon carbide aerogel of example 1 at different temperatures is shown in fig. 4, the thermal conductivity at room temperature is 0.019W/m · K, and the thermal conductivity at high temperature 900 ℃ is only 0.076W/m · K, further, the temperature of the other side of the silicon carbide aerogel of example 1 is only 98.7 ℃ by infrared test after ablation test for 2min by a high temperature spray gun (flame temperature is about 1200 ℃) (as shown in fig. 5, a is the temperature test result without high temperature treatment, b is the result after high temperature treatment for 10s, c is the result after high temperature treatment for 20s, d is the result after high temperature treatment for 30s, e is the result after high temperature treatment for 40s, and f is the result after high temperature treatment for 2 min).
TABLE 1 test results of thermal conductivity of silicon carbide aerogels of examples and comparative examples
(3) Mechanical property test method: mechanical properties of the samples were measured using an electronic universal tester, and the results are shown in table 2, in which the results of the silicon carbide aerogel of example 1 are shown in fig. 6.
TABLE 2 mechanical Property test results for the silicon carbide aerogels of the examples and comparative examples
| Elastic deformation Rate (%) | Fatigue test retention (%) | |
| Example 1 | 50 | 95.2 |
| Example 2 | 50 | 93.9 |
| Example 3 | 50 | 94.8 |
| Example 4 | 50 | 93.2 |
| Example 5 | 50 | 93.5 |
| Example 6 | 50 | 93.1 |
| Comparative example 1 | 50 | 68.4 |
(4) The thermal stability test method comprises the following steps: the thermal stability of the sample was tested by using a thermogravimetric analyzer in an air environment, and the initial temperature rise point of the thermogravimetric curve was taken as the thermal stability temperature, and the test results are shown in table 3, wherein the thermal stability test result of example 1 is shown in fig. 7.
TABLE 3 thermal stability test results of examples and comparative examples
| Temperature of thermal stability (. degree.C.) | |
| Example 1 | 1264 |
| Example 2 | 1252 |
| Example 3 | 1240 |
| Example 4 | 1235 |
| Example 5 | 1230 |
| Example 6 | 1232 |
| Comparative example 1 | 1015 |
(5) The density test method comprises the following steps: the bulk density of the sample was calculated by weighing the mass and volume of the sample and dividing the two, and the test results are shown in table 4.
Table 4 silicon carbide aerogel density test results for examples and comparative examples
| Bulk Density (g/cm)3) | |
| Example 1 | 0.11 |
| Example 2 | 0.1 |
| Example 3 | 0.11 |
| Example 4 | 0.12 |
| Example 5 | 0.13 |
| Example 6 | 0.12 |
| Comparative example 1 | 0.26 |
Examples 1-6 compared to comparative example 1, a laminate structure was used, and the final density of the product was as low as 0.13g/cm3The corresponding fatigue test rate reaches more than 93%, and the mechanical property is obviously improved compared with that of a comparative example; meanwhile, in terms of heat insulation effect, the thermal conductivity of the silicon carbide aerogel of the example of the present invention is lower than 0.025W/mK at room temperature and lower than 0.079W/mK at 900 ℃ which is also significantly superior to that of comparative example 1, and accordingly, the thermal stability temperature thereof is also higher than 1200 ℃.
The above is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the scope of the present invention.
Claims (8)
1. The silicon carbide aerogel is characterized by comprising at least two silicon carbide fiber layers which are stacked, and a gap is formed between every two adjacent silicon carbide fiber layers; each silicon carbide fiber layer comprises a plurality of silicon carbide fibers, and the silicon carbide fibers are mutually crosslinked to form a plurality of holes.
2. A method of preparing the silicon carbide aerogel of claim 1, comprising the steps of:
assembling a plurality of layers of carbon fiber felts into a carbon source body;
soaking the carbon source body in a first solution to obtain a silicon source attachment, wherein the first solution comprises a silicon source and a hydrolyzing agent, and the hydrolyzing agent hydrolyzes the silicon source;
drying the silicon source attachment to obtain a silicon source-carbon fiber compound;
and sintering the silicon source-carbon fiber composite in an inert gas atmosphere to obtain the silicon carbide aerogel.
3. The method of claim 2, wherein in the step of assembling the carbon source body from the plurality of carbon fiber mats, the carbon fiber mats have a density of 0.05 to 0.15g/cm3(ii) a And/or the presence of a gas in the gas,
the thickness of each carbon fiber felt is 0.2-5 mm.
4. The method of preparing a silicon carbide aerogel according to claim 2, wherein the silicon source comprises at least one of methyltrimethoxysilane, dimethyldimethoxysilane, hexamethyldisiloxane, and silicon monoxide; and/or the presence of a gas in the gas,
the hydrolytic agent comprises at least one of deionized water, ethanol and tertiary butanol; and/or the presence of a gas in the gas,
the mass ratio of the silicon source to the hydrolytic agent is (0.1-1): 1.
5. the method for preparing silicon carbide aerogel according to claim 2, wherein in the step of drying the silicon source attachment to obtain the silicon source-carbon fiber composite, the drying temperature is 100 to 150 ℃; and/or the presence of a gas in the gas,
the drying time is 2-10 h.
6. The method of preparing silicon carbide aerogel according to claim 2, wherein the step of sintering the silicon source-carbon fiber composite in an inert gas atmosphere to obtain the silicon carbide aerogel is performed at a temperature of 1300 ℃ to 1700 ℃; and/or the presence of a gas in the gas,
the inert gas comprises at least one of argon and nitrogen; and/or the presence of a gas in the gas,
the sintering time is 0.5-3 h.
7. The method for producing the silicon carbide aerogel according to claim 2, wherein the sintering is performed by sequentially performing a temperature rise step and a temperature hold step, wherein the temperature rise step is performed by raising the temperature to the sintering temperature at 3 to 10 ℃/min, and the temperature hold step is performed by maintaining the sintering temperature for 0.5 to 3 hours.
8. The method of preparing a silicon carbide aerogel according to claim 2, wherein the step of assembling the plurality of layers of carbon fiber mats into the carbon source body is preceded by:
providing a carbon fiber body and separating the carbon fiber body into a plurality of layers of carbon fiber felts.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040033882A1 (en) * | 2002-08-16 | 2004-02-19 | The Boeing Company | Hybrid aerogel rigid ceramic fiber insulation and method of producing same |
| CN102531540A (en) * | 2011-12-28 | 2012-07-04 | 大连理工大学 | Preparation method of composite nanofiber aerogel material |
| CN107099692A (en) * | 2016-02-20 | 2017-08-29 | 金承黎 | A kind of fibre-reinforced aerogel-metallic composite and preparation method thereof |
| CN111454041A (en) * | 2020-04-10 | 2020-07-28 | 中山火炬职业技术学院 | Preparation method of fiber-reinforced silica aerogel |
| CN112830762A (en) * | 2021-02-25 | 2021-05-25 | 辽宁金谷炭材料股份有限公司 | Preparation method of silicon carbide aerogel heat-insulating material |
| CN114100534A (en) * | 2021-11-12 | 2022-03-01 | 中国科学技术大学先进技术研究院 | Preparation method of silicon-aluminum binary aerogel composite material |
-
2022
- 2022-04-14 CN CN202210392619.6A patent/CN114716229B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040033882A1 (en) * | 2002-08-16 | 2004-02-19 | The Boeing Company | Hybrid aerogel rigid ceramic fiber insulation and method of producing same |
| CN102531540A (en) * | 2011-12-28 | 2012-07-04 | 大连理工大学 | Preparation method of composite nanofiber aerogel material |
| CN107099692A (en) * | 2016-02-20 | 2017-08-29 | 金承黎 | A kind of fibre-reinforced aerogel-metallic composite and preparation method thereof |
| CN111454041A (en) * | 2020-04-10 | 2020-07-28 | 中山火炬职业技术学院 | Preparation method of fiber-reinforced silica aerogel |
| CN112830762A (en) * | 2021-02-25 | 2021-05-25 | 辽宁金谷炭材料股份有限公司 | Preparation method of silicon carbide aerogel heat-insulating material |
| CN114100534A (en) * | 2021-11-12 | 2022-03-01 | 中国科学技术大学先进技术研究院 | Preparation method of silicon-aluminum binary aerogel composite material |
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