High-temperature-resistant heteromorphic nanocrystalline aerogel material and preparation method thereof

Abstract

The invention relates to a high-temperature-resistant heteromorphic nanocrystalline aerogel material and a preparation method thereof. The method is as follows: preparing heteromorphic nanocrystal dispersion liquid; mixing the heteromorphic nanocrystal dispersion liquid and an assembly agent evenly by stirring and ultrasonic treatment to obtain a mixture phase first solution; then adding a catalyst solution, performing a gelation reaction process by stirring and ultrasonic treatment, and then performing a vacuum pumping process to obtain gelation reaction liquid; and performing an aging step and a drying step to obtain a heteromorphic nanocrystalline aerogel material; the heteromorphic nanocrystalline aerogel material is subjected to post-treatment in two or more different temperature stages to obtain the high temperature-resistant heteromorphic nanocrystalline aerogel material. The invention performs a staged heat treatment process on the aerogel material in the post-treatment process, thereby realizing the strengthening and toughening of themicrostructure of the aerogel material, so that the structural strength of the aerogel material is remarkably improved, the high temperature resistance performance and the large specific surface area after the heat treatment are realized, and the preparation of the high-temperature-resistant heteromorphic nanocrystalline aerogel material capable of high-efficient heat insulation is realized.

Description

technical field [0001] The invention relates to the technical field of airgel preparation, in particular to a high-temperature-resistant special-shaped nanocrystalline airgel material and a preparation method thereof. Background technique [0002] Nanoporous airgel (airgel for short) material is a kind of gel material whose dispersion medium is gas. It is a nanoporous solid material with a network structure composed of colloidal particles or polymer molecules. The size of the pores in the material is on the order of nanometers. Its porosity is as high as 80-99.8%, the typical size of the pores is 1-100nm, and the specific surface area is 200-1000m 2 / g, while the density can be as low as 3kg / m 3 , while the thermal conductivity at room temperature can be as low as 0.012W / m·k. It is precisely because of these characteristics that airgel materials have broad application potential in thermal, acoustic, optical, microelectronics, and particle detection. At present, the most ...

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Problems solved by technology

Carbon aerogels and ceramic aerogels have good high temperature resistance, but there are certain limitations in their application, that is, thermal insulation applications above 1400 °C can only be achieved in an oxygen-free environment, while carbon aerogels and ceramic aerogels There is no effective way to overcome the antioxidant

Oxide aerogels such as silica, alumina, and zirconia will undergo severe crystal transformation and sintering at high temperatures, leading to structural collapse, resulting in the growth of nanoparticles and the reduction of pores, so that the specific surface area of ​​the aerogel will decrease sharply. decline, greatly weakening its thermal insulation performance and failure of thermal insulation

Aiming at the limitations of oxide aerogels, related studies have carried out modification processes such as rare earth metal oxides or multi-component doping, but their effects are limited

[0004] Chinese patent application CN201810068117.1 discloses a method for preparing high-temperature-resistant airgel materials, although the airgel prepared by this method has good high-temperature resistance characteristics, and the heat-resistant temperature is above 1000°C, and can even withstand above 1300°C High temperature, but the airgel material will still produce a series of phase transitions at high temperatures above 1200 ° C, making its specific surface area after high-temperature heat treatment small, no more than 100m 2 / g, so the high temperature insulation performance of the airgel material is not very good

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