A gradient doped structure of silica airgel opacifier

Abstract

The invention provides an aerosil opacifier gradient doping structure, and is characterized in that a silicon carbide opacifier material with advantages of high density, small particle size, low density and high temperature resistance can be employed at a high temperature segment of the aerogel material; and the carbon black material opacifier with advantages of low concentration and large particle size can be employed at a low temperature segment. Under condition of doping the opacifier, solid phase thermal conductivity of the material is considered, radiation thermal conductivity of the material is greatly reduced, solid phase thermal conductivity of the aerogel material can be increased, the chemical stability of the doped aerogel material can be ensured, effective thermal conductivity of the material can be effectively reached, heat insulation effect of the material can be increased, application requirements of aviation spaceflight, military material and industrial high temperature thermal protection can be satisfied, and the gradient doping structure has strong practicality.

Description

technical field [0001] The invention belongs to the technical field of nanometer thermal insulation materials, and in particular relates to a gradient doping structure of a silica airgel opacifying agent. Background technique [0002] With the development of aerospace technology, the speed and flight time of aircraft continue to increase, and the requirements for thermal insulation materials are becoming more and more stringent. At this time, radiation heat transfer is dominant, so the use of nanotechnology to design and develop high-temperature-resistant, low-radiation thermal conductivity airgel composites has become the focus of high-temperature thermal protection for aerospace. Silica airgel is a super thermal insulation material with nanoporous structure. Silica airgel has extremely low density and high porosity, and its staggered nanoporous network structure can effectively inhibit heat conduction and heat convection. Solid material with excellent thermal properties....

AI Technical Summary

Problems solved by technology

However, due to the low absorption characteristics of aerogels with silica as the main material to high-temperature near-infrared wavelengths, pure silica airgel materials have extremely high radiation thermal conductivity, so it is difficult to make pure silica airgel The material is directly applied for high-temperature thermal protection, so opacifier doping is required to effectively suppress radiative heat transfer

The shading effect and temperature tolerance of different shading materials are different. The optimal doping particle size of the shading agent is closely related to the temperature, and the doping of the shading agent will lead to an increase in the solid-phase thermal conductivity. Therefore, it is urgent to propose a new Silica Airgel Opacifier Doped Structure

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