A kind of preparation method of alumina-silica aerogel thermal insulation composite material

A technology of silica airgel and composite materials, which is applied in the field of heat insulation materials, can solve problems such as high manufacturing costs, complicated process flow, and potential safety hazards, and achieve the effects of simple preparation methods, green preparation processes, and low manufacturing costs

Active Publication Date: 2021-05-25
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

However, the preparation of the above-mentioned alumina-silica airgel needs to use organoaluminum compound (aluminum isopropoxide) as the aluminum source of the aerogel, and an organosilicon compound (tetraethyl silicate) as the silicon source of the aerogel, After four steps of sol-gel, aging, solvent replacement and supercritical drying, a large amount of flammable and explosive organic solvent-ethanol is used in the solvent replacement, and the waste solvent generated requires additional post-processing; the drying process requires It is also prepared by supercritical drying process with ethanol as the drying medium. Due to the flammable and explosive characteristics of ethanol, the explosion-proof requirements of the supercritical drying equipment system are high, and there are great safety hazards in the drying process, complicated process flow and dangerous The supercritical drying process makes the existing alumina-silica airgel thermal insulation composite materials more expensive to manufacture, which limits its large-scale application in the field of thermal insulation
Although there are also inorganic aluminum compounds as aluminum sources (Wu X, et al. Novel Al 2 o 3 – SiO 2 Composite aerogels with high specific surface area at elevated temperatures with different alumina / silica molar ratios prepared by a non-alkoxide sol-gel method, RSC Advances, 2016(6): 5611-5620.) or organic solvent replacement process (Yang J, et al. Facile one-stepprecursor-to-aerogel synthesis of silica-dopedalumina aerogels with high specific surface area at elevated temperatures, Journal of Porous Materials, 2017(24):889-897.) or non-supercritical drying process (Ji X, et al. Synthesis of analumina enriched Al 2 o 3 -SiO 2 aerogel: Reinforcement and ambient pressure drying, Journal of Non-Crystalline Solids, 2017(471): 160-168.) A research report on the preparation of alumina-silica aerogels, but their raw materials still cannot abandon organic aluminum or inorganic aluminum at the same time Compound as aluminum source, organosilicon source (orthosilicate as silicon source), ethanol (as solvent for preparing sol), organic solvent replacement and ethanol as drying medium supercritical drying process

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  • A kind of preparation method of alumina-silica aerogel thermal insulation composite material
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  • A kind of preparation method of alumina-silica aerogel thermal insulation composite material

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preparation example Construction

[0036] like figure 1 As shown, the preparation method of an alumina-silica airgel thermal insulation composite material provided by the present invention includes preparing fiber preforms, preparing alumina-silica sol, vacuum impregnation, gel aging, hydrothermal assisted drying, Drying in 6 steps. Specifically:

[0037] In the first step, the fiber preform is prepared by:

[0038] Forming molds are adopted (the volume of the mold is selected according to the volume of the alumina-silica airgel thermal insulation composite material to be prepared, and the volume of the alumina-silica airgel thermal insulation composite material is equal to the volume of the fiber prefabricated part, so the mold The volume of the fiber preform can be just enough to hold the fiber prefabricated part) Clamp and fix a certain quality of inorganic ceramic fiber to form a fiber prefabricated part. Before clamping, the apparent density of the inorganic ceramic fiber is 0.15-0.30g / cm 3 (Fiber mass ...

Embodiment 1

[0054] A preparation method of alumina-silica airgel thermal insulation composite material, comprising the following steps:

[0055] (1) Preparation of fiber preforms

[0056] Use a mold to clamp and fix a certain quality of mullite fiber to form a fiber prefabricated part. Before clamping, the apparent density of the mullite fiber is 0.15g / cm 3 , and make the mullite fiber arrangement direction perpendicular to the heat flow direction during heat insulation to obtain the mullite fiber preform.

[0057] (2) Preparation of alumina-silica sol

[0058] First, the commercially available water-based alumina sol (15% solid content, Zibo Jinqi Chemical Technology Co., Ltd.) and the commercially available water-based silica sol (15% solid content, Hangzhou Wanjing New Material Co., Ltd.) were mixed and stirred for 10 minutes, and then Add ammoniacal liquor to the above-mentioned mixed sol, continue to stir for 30min, and obtain an alumina-silica sol with a solid content of 15%, the ...

Embodiment 2~11

[0070] In the process of preparing the fiber preform in the first step of the present invention, the fiber type basically has no effect on the high temperature thermal conductivity and mechanical properties of the composite material, but the fiber apparent density has an important influence on the high temperature thermal conductivity and mechanical properties of the composite material. Appropriately increasing the apparent density can further reduce the high-temperature thermal conductivity of the material and improve the mechanical properties of the material, but the fiber type and apparent density have little effect on the temperature resistance of the material (heat treatment at 1500°C for 1800s, the thickness shrinkage rate is average less than 1.5%). In the second step of preparing the alumina-silica sol, the addition of the catalyst is to control the gelation time of the sol, which basically has no effect on the final performance of the material; the increase in the soli...

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Abstract

The invention belongs to the technical field of heat insulation materials, and discloses a preparation method of an alumina-silica airgel heat insulation composite material. The preparation method of the invention adopts alumina and silica sol with water as a solvent, and inorganic ceramic fibers as Reinforcement phase, through six simple process steps of preparing fiber prefabricated parts, preparing alumina-silica sol, vacuum impregnation, gel aging, hydrothermal assisted drying, and drying, a high-temperature resistant, low thermal conductivity, high-strength oxidation Aluminum-silica airgel thermal insulation composites. The preparation method of the material adopts raw materials without organic aluminum / inorganic aluminum / organosilicon compounds. During the preparation process, there is no organic solvent replacement and no flammable and explosive ethanol solvent is used as a drying medium. The raw materials and preparation process are green, environmentally friendly and safe. The manufacturing cost is low, and it is easy for mass production and large-scale application.

Description

technical field [0001] The invention relates to the technical field of thermal insulation materials, in particular to a preparation method of an alumina-silica airgel thermal insulation composite material. Background technique [0002] Nano-airgel thermal insulation composite materials have the advantages of light weight, high temperature resistance, and low thermal conductivity, and are currently a research hotspot in the field of high-performance thermal insulation (Zhao S, et al. Additive manufacturing of silica aerogels, Nature, 2020(584) : 387-392.). For example, silica airgel thermal insulation composite material is currently the most studied airgel thermal insulation composite material that has been applied on a large scale. Its high temperature thermal conductivity is extremely low, and its thermal conductivity at 800 °C is only 0.038W / m•K (Feng Jian, et al. Airgel high-efficiency thermal insulation materials, Science Press, 2016.11.), has been widely used in high-...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B30/02
CPCC04B30/02C04B2201/20C04B2201/32C04B2201/50C04B14/064C04B14/303C04B14/302C04B14/46
Inventor 姜勇刚冯坚冯军宗李良军
Owner NAT UNIV OF DEFENSE TECH
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