High-temperature-resistant and low-density aluminum oxide nanorod aerogel and preparation method thereof

A kind of aluminum oxide nano and airgel technology, applied in the direction of alumina/aluminum hydroxide, etc., can solve the problems of insufficient temperature resistance, achieve improved temperature resistance, high specific surface area retention rate, avoid sintering and large specific surface area Falling effect

Pending Publication Date: 2022-04-26
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention provides an alumina nanorod aerogel and its preparation method and application, which are used to overcome defects such as insufficient temperature resistance of pure alumina aerogels in the prior art

Method used

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  • High-temperature-resistant and low-density aluminum oxide nanorod aerogel and preparation method thereof
  • High-temperature-resistant and low-density aluminum oxide nanorod aerogel and preparation method thereof
  • High-temperature-resistant and low-density aluminum oxide nanorod aerogel and preparation method thereof

Examples

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preparation example Construction

[0026] The present invention proposes a kind of preparation method of aluminum oxide nanorod aerogel, such as figure 1 shown, including the following steps:

[0027] S1: Aluminum isopropoxide (Al(OCHCH 3 CH 3 ) 3 ) mixed with deionized water under stirring conditions, heated to 50-80°C, and kept at 50-80°C for 0.5-3h, then heated from 50-80°C to 85-100°C, and heated at 85-100°C Keeping it warm for 0.5-2 hours, adding an acid substance as a shape regulator, performing a hydrothermal reaction, cooling to room temperature, and obtaining aluminum oxide nanorods.

[0028] Incubate at 50-80°C for 0.5-3 hours to obtain a fully hydrolyzed alumina solution.

[0029] Incubate at 85-100°C for 0.5-2 hours to evaporate the isopropanol produced by hydrolysis.

[0030] Preferably, the molar ratio of the aluminum isopropoxide to deionized water is (10-50):1; the molar ratio of the acidic substance to the aluminum isopropoxide is 4-18:1.

[0031] Preferably, the acid is one of dilute hyd...

Embodiment 1

[0048] This embodiment provides a method for preparing alumina nanorod airgel, comprising the following steps:

[0049] S1: Aluminum isopropoxide (Al(OCHCH 3 CH 3 ) 3 ) and deionized water (H 2 O) After mixing under stirring conditions, heat to 70°C and keep it warm for 5h to obtain a fully hydrolyzed alumina hydrolyzate; further raise the temperature to 90°C and keep it warm for 0.5h, evaporate the isopropanol produced by hydrolysis, and get alumina sol ; The alumina sol and acetic acid are fully mixed according to the ratio of 10:1, then placed in a hydrothermal kettle, heated to 160 ° C and kept for 10 hours, and then cooled to room temperature to obtain a dispersion of alumina nanorods.

[0050] S2: Fully mix resorcinol and deionized water under stirring, add sodium carbonate solution dropwise to the solution after fully dissolved, stir for 30 minutes, add a certain amount of formaldehyde to the mixture, stir for a period of time Stand still for 1 hour to obtain resorc...

Embodiment 2

[0055] This example provides a method for preparing alumina nanorod airgel. Compared with Example 1, in step S4, the alumina / carbon composite airgel material is placed in an air atmosphere and the temperature is 800 ° C. Under heat treatment for 5 hours, a high temperature resistant, low density alumina nanorod aerogel was obtained. Other processes are with embodiment 1.

[0056] The high-temperature-resistant alumina nanorod aerogel prepared in this example was tested for temperature resistance, and it was found that the specific surface area of ​​the sample after 1300°C heat test (air atmosphere) for 30 minutes was 72m 2 / g, there is no obvious change on the surface of the sample and no cracking and structural collapse; the specific surface area of ​​the sample after 1400 ℃ heat assessment (air atmosphere) for 30 minutes is 26m 2 / g, there is no obvious change on the surface of the sample and no cracking or structural collapse occurs, indicating that it can withstand high t...

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Abstract

The invention discloses high-temperature-resistant and low-density aluminum oxide nanorod aerogel and a preparation method thereof. The preparation method comprises the following steps: firstly preparing an aluminum oxide nanorod, and then coating the aluminum oxide nanorod by taking resorcinol-formaldehyde as a carbon source. Gelling, aging and performing supercritical drying; through high-temperature cracking, resorcinol-formaldehyde is converted to a carbon shell layer in the high-temperature cracking process, and contractility generated in the conversion process effectively inhibits crystal phase conversion and lattice rearrangement of core layer aluminum oxide to an alpha phase at a high temperature, so that sintering caused by rapid growth of alpha-phase crystal grains and great reduction of the specific surface area are avoided. And finally, carrying out heating treatment to remove the carbon template, so as to obtain the aluminum oxide nanorod aerogel with the three-dimensional network structure. The alumina nanorod aerogel prepared by the invention has good high temperature resistance, and can be applied to the fields of thermal insulation and heat preservation of aerospace, petrochemical engineering, industrial kilns and the like.

Description

technical field [0001] The invention relates to the technical field of airgel preparation, in particular to a high-temperature-resistant, low-density aluminum oxide nanorod airgel and a preparation method thereof. Background technique [0002] Airgel is a new type of nanomaterial with a three-dimensional porous network structure with solid as the skeleton and gas as the dispersion medium. It exhibits excellent properties such as high specific surface area, high porosity, and low density. Sensing, heat insulation and other fields have great application prospects. SiO 2 Airgel is a well-researched airgel thermal insulation material at present, but when it is at a high temperature above 800°C, the grains will grow rapidly, showing structural collapse and performance degradation. Carbon aerogels have good high temperature resistance and can withstand high temperatures above 1800 °C in an oxygen-free environment, but their insufficient oxidation resistance severely limits their...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
CPCC01F7/021C01F7/025C01P2002/72C01P2004/03C01P2004/01C01P2006/12C01P2006/13C01P2006/32C01P2006/10
Inventor 冯坚柳凤琦姜勇刚冯军宗李良军
Owner NAT UNIV OF DEFENSE TECH
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