Bulk silicon carbide aerogel material and preparation method thereof

A technology of silicon carbide and aerogel, applied in chemical instruments and methods, carbon compounds, inorganic chemistry, etc., can solve problems such as limiting the application of materials, and achieve the effects of wide application range, low cost, and simple process

Active Publication Date: 2013-01-30
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, most of these methods obtain whiskers or nanoparticles, which greatly limits the application of materials, such as the preparation method of a mesoporous SiC material reported in our Chinese patents CN102674355A and CN102674354A. Although this method is simple and practical, but The resulting product is SiC nanopowder

Method used

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  • Bulk silicon carbide aerogel material and preparation method thereof
  • Bulk silicon carbide aerogel material and preparation method thereof
  • Bulk silicon carbide aerogel material and preparation method thereof

Examples

Experimental program
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Effect test

example 1

[0026] Mix catechol, formaldehyde, 3-aminopropyltriethoxysilane, tetraethylorthosilicate, water, and ethanol in a molar ratio of 1:2:0.4:1.6:4:17, seal and place Carry out sol-gel reaction at room temperature of 20°C to obtain a wet gel. The wet gel is aged in an oven at 40°C for 24 hours. After taking out the wet gel, continue to dry it in an oven at 40°C for 24 hours to obtain a block RF -SiO 2 Composite airgel, the RF-SiO 2 The composite airgel was placed in a tube furnace, and the temperature was raised to 1500°C at a rate of 1°C / min under the protection of argon, and the temperature was lowered to 500°C after 10 hours of heat preservation, and then the argon was replaced by air , after 4 hours of heat preservation, it was cooled to room temperature to obtain a bulk silicon carbide airgel material. The apparent density of silicon carbide airgel material is 0.215g / cm 3 , BET specific surface area is 291m 2 / g, the pore size distribution is 10~70nm.

[0027] See attache...

example 2

[0031] Mix catechol, formaldehyde, 3-aminopropyltriethoxysilane, tetraethylorthosilicate, water, and ethanol in a molar ratio of 1:2:2.4:0.6:6:14, seal and place Perform sol-gel reaction at room temperature at 25°C to obtain a wet gel. The wet gel is aged in an oven at 50°C for 18 hours. After taking out the wet gel, continue to dry it in an oven at 50°C under normal pressure for 18 hours to obtain a block RF -SiO 2 Composite airgel, the RF-SiO 2 The composite airgel is placed in a tube furnace, and the temperature is raised to 1550°C at a rate of 1°C / min under the protection of argon, and the temperature is lowered to 600°C after 10 hours of heat preservation, and then the argon is replaced by air , after 2 hours of heat preservation, it was cooled to room temperature to obtain a block silicon carbide airgel material. The apparent density of silicon carbide airgel material is 0.221g / cm 3 , BET specific surface area is 130m 2 / g, the pore size distribution is 30~100nm.

...

example 3

[0037] Mix catechol, formaldehyde, 3-aminopropyltriethoxysilane, tetraethylorthosilicate, water, and ethanol in a molar ratio of 1:2:1.5:1.5:6:25, seal and place Perform sol-gel reaction at room temperature at 20°C to obtain a wet gel. The wet gel is aged in an oven at 60°C for 12 hours. After taking out the wet gel, continue to dry it in an oven at 60°C for 12 hours to obtain a block RF-SiO 2 Composite airgel, the RF-SiO 2 The composite airgel was placed in a tube furnace, and the temperature was raised to 1600°C at a rate of 1°C / min under the protection of argon. After 5 hours of heat preservation, the temperature was lowered to 600°C, and then the argon was replaced by air. , after 2 hours of heat preservation, it was cooled to room temperature to obtain a block silicon carbide airgel material. The apparent density of silicon carbide airgel material is 0.205g / cm 3 , BET specific surface area is 330m 2 / g, the pore size distribution is 10~100nm.

[0038] See attached pi...

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Abstract

The invention belongs to the technical field of preparation of bulk silicon carbide mesoporous materials, and relates to a bulk silicon carbide aerogel material and a preparation method thereof. The silicon carbide aerogel is a celadon bulk material, the pore size distribution is 10-100 nm, the BET (Brunauer, Emmett and Teller) specific surface area is 130-330 m2/g, and the apparent density is 0.200-0.300 g/cm3. The preparation method comprises the following steps of: preparing RF-SiO2 composite aerogel from benzenediol, formaldehyde, a silicon source, water and alcohol by using the one-pot method through sol-gel, aging and ambient pressure drying, carrying out a carbothermic reduction reaction on the RF-SiO2 composite aerogel under the protection of argon, and calcining the reaction product in the air to obtain the bulk silicon carbide aerogel material. The bulk silicon carbide mesoporous material has the advantages of simple and cheap raw materials, and the method has simple and direct process, is easy to control and is easy to realize mass production and the like.

Description

technical field [0001] The invention belongs to the field of preparation technology of massive carbide mesoporous materials, and in particular relates to a massive silicon carbide airgel material and a preparation method thereof. Background technique [0002] Airgel is a nanoporous material formed by the aggregation of nanoparticles. It has many special properties, such as high specific surface area, low density, high porosity, and low thermal conductivity. It is the lightest and most effective thermal insulation material found so far. Good solid material. In the field of thermal insulation, the most researched is SiO 2 Aerogels and carbon aerogels. SiO 2 The normal service temperature of airgel and its composite materials is 600~800°C, the pore structure is obviously reduced above 800°C, the material tends to be dense, and the pore structure completely disappears above 1000°C. Although carbon aerogels have good high temperature resistance in an inert atmosphere, the ope...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/36C01B32/977
Inventor 沈晓冬孔勇崔升仲亚
Owner NANJING UNIV OF TECH
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