Improvement in the high temperature thermal insulation performance of Y2O3 opacified silica aerogels

Abstract

To improve the high-temperature thermal insulation characteristics of silica aerogels, it is important to reduce the radiative heat transfer. This can be achieved by Y2O3 doping in the silica sol to opacify the infrared radiation of silica aerogels. The purpose of the present work was to study the effect of Y2O3 incorporation on the structural and physicochemical properties of opacified silica aerogels prepared by a simple ambient pressure drying method. The influence of Y2O3 addition on specific extinction coefficient and high temperature thermal insulation of prepared aerogels were investigated. The synthesized aerogels were lightweight and crack-free, with a granular, nanoporous morphology. The specific surface area, pore diameter, and bulk density of the prepared samples were 917.5–937.6 m2/g, 5.64–6.58 nm, and 0.047–0.076 g/cm3, respectively. The thermal conductivity of opacified silica aerogel at 1000 K was 0.080 W/(m.K), which was lower than the unopacified silica aerogel and it was around 0.104 W/(m.K) at same temperature.