High temperature resistant Si-C-O aerogel thermal insulation composite material and preparation method thereof

A technology of composite materials and airgel, which is applied in the field of preparation of airgel thermal insulation composite materials, can solve the problems of low mechanical strength of Si-C-O airgel, achieve low high-temperature thermal conductivity, reduce heat conduction, and high-temperature insulation good thermal performance

Active Publication Date: 2012-07-25
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the problems of low mechanical strength of existing Si-C-O airgel, the present invention provides a preparation method of Si-C-O airgel thermal insulation composite material which is resistant to high temperature and has good thermal insulation performance and mechanical properties

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The product in this example is composed of mullite fiber and Si-C-O airgel, the silicon source is ethyl orthosilicate, the carbon source is dimethyldiethoxysilane, the alcohol solvent is absolute ethanol, and the acid catalyst is hydrochloric acid , the alkali catalyst is ammonia water, and the raw material molar ratio of the precursor sol is ethyl orthosilicate: dimethyldiethoxysilane: absolute ethanol: deionized water: hydrochloric acid: ammonia water=1:1.5:6:6:2 ×10 -3 : 6×10 -2 , the preparation process is as follows: (1) Mix and stir ethyl orthosilicate, dimethyldiethoxysilane, hydrochloric acid, deionized water, and half of the required amount of absolute ethanol for 30 minutes and then let stand for 5 hours; (2 ) Add ammonia water and the other half of absolute ethanol to the mixed solution and continue to stir for 20 minutes to obtain the Si-C-O airgel precursor sol; (3) Add the Si-C-O airgel precursor sol to a container with a volume fraction of 5 % of the mu...

Embodiment 2

[0036] The product of this embodiment is made of carbon fiber and Si-C-O airgel.

[0037] The fiber felt is a carbon fiber felt with a volume fraction of 8%, and the diameter of the carbon fiber is 7mm. Other processes are the same as in Example 1 except this.

[0038] The obtained Si-C-O airgel has a specific surface area of ​​217m / g 2 , the obtained Si-C-O airgel thermal insulation composite material has a flexural strength of 2.4MPa, a thermal conductivity of 0.051W / m K at 1200°C, and a shrinkage rate of 4.8% after heat treatment at 1200°C for 2 hours.

Embodiment 3

[0040] The product of this embodiment is made of aluminum silicate fiber and Si-C-O airgel.

[0041] The fiber mat is an aluminum silicate fiber mat with a volume fraction of 7%, and the diameter of the aluminum silicate fiber is 10mm. Other processes are the same as in Example 1 except this.

[0042] The obtained Si-C-O airgel thermal insulation composite material has a tensile strength of 1.45MPa and a thermal conductivity of 0.044W / m·K at 1000°C.

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Abstract

The invention relates to a high temperature resistant Si-C-O aerogel thermal insulation composite material and a preparation method thereof. The preparation method comprises the following steps: mixing an Si source and a C source, and carrying out hydrolysis and condensation polymerization to form a sol which has a nanometer porous three-dimensional network skeleton structure and contains three elements of Si, C, and O in the network structure; compositing the sol with a high temperature resistant inorganic ceramic fiber to form a fiber-gel mixture; carrying out supercutical fluid drying to obtain an Si-C-O aerogel precursor composite material with the nanometer porous structure; and cracking the Si-C-O aerogel precursor composite material in high temperature inert atmosphere to form the Si-C-O aerogel thermal insulation composite material with an Si-O bond and an Si-C bond coexisting. The thermal conductivities of the Si-C-O aerogel thermal insulation composite material prepared in the invention at 800DEG C, 1000DEG C, and 1200DEG C are low to 0.32W / m.K, 0.043 W / m.K, and 0.051 W / m.K respectively, and the bending strength of the Si-C-O aerogel thermal insulation composite materialis 2.6MPa, so the Si-C-O aerogel thermal insulation composite material can satisfy stringent thermal insulation requirements by aerospace fields, military fields and civil fields.

Description

technical field [0001] The invention relates to a preparation method of an airgel heat-insulating composite material, in particular to a preparation method of an airgel heat-insulation composite material obtained by compounding high-temperature-resistant Si-C-O airgel and inorganic ceramic fibers. Background technique [0002] In the future, when aerospace vehicles develop in the direction of high Mach number and long endurance, the outer surface of the aircraft will be subjected to a large amount of aerodynamic heating, the surface temperature will be high, and the requirements for the heat-resistant structure will be more stringent. In terms of civilian use, global energy is increasingly scarce, and some high-temperature fields such as aircraft engines, oil pipelines, furnaces and other thermal equipment also put forward higher requirements for thermal insulation materials. Traditional heat insulation materials such as ceramic fiber felts and ceramic heat insulation tiles ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B30/02
Inventor 冯坚姜勇刚张长瑞冯军宗赵南
Owner NAT UNIV OF DEFENSE TECH
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