Method for preparing heat-resisting alumina-silox aerogel thermal-protective composite material

A technology of silica airgel and composite materials, which is applied in the field of high-temperature-resistant airgel heat-insulation composite materials and its preparation, can solve the problems of poor infrared radiation blocking ability, high thermal conductivity of materials, and easy agglomeration, etc., and achieve high temperature Improve the heat insulation effect, inhibit the heat conduction of high temperature infrared radiation, and solve the effect of dispersion unevenness

Active Publication Date: 2010-08-04
NAT UNIV OF DEFENSE TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent CN1730388A discloses a preparation method of porous powder-doped silica airgel thermal insulation material, by adding fibers, opacifiers and porous silica powder to the hydrolyzed silica sol, through gel aging and supercritical The silica airgel thermal insulation material is obtained by drying. The compressive strength of the material is 1.2-1.8 MPa, but due to the addition of silica powder and opacifying agent, it is easy to agglomerate, and the thermal conductivity of the material is relatively high, and its thermal conductivity at room temperature is 0.05- 0.08W / m·K
Chinese patent CN1724354A discloses a method of improving SiO 2 A method for the thermal stabilization of airgel by using SiO 2 Aerogel doped with Fe 2 o 3 Nanoparticles are used to overcome the disadvantages of poor stability and low mechanical strength of airgel in practical applications. After heat treatment at 1000 °C, the specific surface area of ​​airgel still reaches 138-148m 2 / g
[0016] However, Al 2 o 3 -SiO 2 The inherent low strength, high brittleness, poor ability to block infrared radiation, and difficulty in forming airgel materials limit the Al 2 o 3 -SiO 2 Application of airgel in industry

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0053] (1) Mix aluminum sec-butoxide, absolute ethanol, and deionized water in a molar ratio of 1:16:0.6, and heat to 60? Stir for 45min to form a colorless transparent sol, and when the sol drops to room temperature, Al 2 o 3 Sol; (2) ethyl orthosilicate, absolute ethanol, deionized water and hydrochloric acid in molar ratio 1: 5: 1: 3.6 × 10 -3 Mix, stir for 20min, let stand for 1h, get SiO 2 sol; (3) two kinds of sols are mixed according to the ratio of Al / Si molar ratio being 3: 1, add methanol, deionized water and glacial acetic acid mixture, wherein methanol, deionized water and glacial acetic acid and sec-butoxide aluminum mole The ratio is 5:0.168:0.448:1 to obtain Al 2 o 3 -SiO 2 Sol; (4) polycarbosilane (PCS) is mixed with xylene solution in a mass ratio of 0.05:0.95, impregnated with a fiber volume fraction of 5% mullite fiber felt or preform, and then cracked at 1200 ° C for 2 hours , to obtain mullite fiber felt or prefabricated parts containing SiC coating; (...

Embodiment 2

[0056] Mix aluminum nitrate, isopropanol, and deionized water in a molar ratio of 1:12:0.6, heat to 80°C with a reflux device and stir for 50 minutes. When the sol drops to room temperature, Al 2 o 3 Sol; methyl orthosilicate, absolute ethanol, deionized water and acetic acid in a molar ratio of 1:3:1:1.8×10 -3 Mix, stir for 20min, let stand for 1h, get SiO 2 sol; then the two sols are mixed in the ratio of 8:1 by Al / Si molar ratio, add methanol, deionized water and glacial acetic acid mixture, wherein the mol ratio of methanol, deionized water and glacial acetic acid to aluminum sec-butoxide is 6:0.1:0.622:1, to get Al 2 o 3 -SiO 2 Sol; polycarbosilane (PCS) and xylene solution are mixed in a mass ratio of 0.10:0.90, impregnated with a zirconia fiber mat or preform with a fiber volume fraction of 7%, and then cracked at 1200 ° C for 2 hours to obtain SiC containing Coated zirconia fiber mats or preforms; Al 2 o 3 -SiO 2 Add the sol to the SiC-coated zirconia fiber fel...

Embodiment 3

[0059] Mix aluminum isopropoxide, absolute ethanol, and deionized water in a molar ratio of 1:32:4, heat to 60°C with a reflux device and stir for 50 minutes. When the sol drops to room temperature, Al 2 o 3 Sol; water glass, absolute ethanol, deionized water and hydrochloric acid in a molar ratio of 1:5:2:3.6×10 -3 Mix, stir for 20min, let stand for 1h, get SiO 2 sol; then the two sols are mixed according to the ratio of Al / Si molar ratio of 1:4, and ammonia water and deionized water are added, wherein the molar ratio of deionized water and ammonia water to water glass is 0.25:7.2×10 -3 : 1, get Al 2 o 3 -SiO 2 Sol; mix polycarbosilane (PCS) and xylene solution at a mass ratio of 0.15:0.85, impregnate a quartz fiber mat or preform with a fiber volume fraction of 9%; then crack at 900°C for 2 hours to obtain a SiC-coated layer of quartz fiber mat or preform; the Al 2 o 3 -SiO 2 Add the sol to the SiC-coated quartz fiber felt or the preform mold to compound the two. Aft...

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Abstract

The invention discloses a method for preparing a heat-resisting alumina-silox aerogel thermal-protective composite material, which comprises the following steps: (1) preparing Al2O3 sol; (2) preparing SiO2 sol; (3) preparing Al2O3-SiO2 sol, (4) preparing SiC coating-containing reinforcing fibers; (5) mixing the SiC coating-containing reinforcing fiber felts or fiber prefabricated members and the Al2O3-SiO2 sol; (6) aging; and (7) carrying out drying treatment by using supercritical fluid. The operating temperature of the Al2O3-SiO2 aerogel composite material prepared by the method can reach 1,200 DEG C; and therefore, the Al2O3-SiO2 aerogel composite material has good heat-insulating property and good mechanical property.

Description

technical field [0001] The invention relates to a high-temperature-resistant airgel heat-insulating composite material and a preparation method thereof, in particular to a SiC-coated ceramic which uses high-temperature-resistant alumina silicon oxide airgel as a matrix and contains SiC coating ceramics that block the heat transfer effect of infrared radiation. Airgel thermal insulation composite material with fiber as reinforcement phase and its preparation method. Background technique [0002] With the rapid development of the aerospace industry, future aerospace vehicles will fly at higher speeds and longer flight times, which will lead to more severe aerodynamic heating on their surfaces and worse thermal environments. The problem of heat protection has become a major technical problem that cannot be avoided and must be properly resolved in the development of new aerospace vehicles. [0003] Therefore, in the thermal protection system of aerospace vehicles, the use of ne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/24C04B14/38
Inventor 张长瑞冯坚姜勇刚曹峰胡海峰高庆福冯军宗
Owner NAT UNIV OF DEFENSE TECH
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