Preparation and properties of low-density and high-temperature resistant yttrium doped silica aerogels

Silica aerogels have attracted extensive attention due to their unique nano-network structure. However, they tend to sinter and cause structural collapse at elevated temperatures, the long-term-use temperature confines to 800 °C. In this paper, yttrium doped silica aerogels (Y-SiO2 aerogels) were prepared by doping yttrium nitrate solution during SiO2 sol-gel process, which showed ultra-low density, complete shape, large specific surface area and nanoporous morphology. Furthermore, the effect of yttrium content on structure and thermal stability was studied. Doped yttrium formed Y-O-Si bonds with silicon, which hindered the polymerization of silica particles and improved the stability of silica aerogels. Meanwhile, introduced yttrium can reduce the thermal conductivity of SiO2 aerogels. After calcined at 1100 °C, Y-SiO2 aerogels still maintain non-crystalline with a high specific surface area of 138.97 m2/g. Simultaneously, the thermal conductivity of Y-SiO2 aerogels is as low as 0.10 W/m·K, much lower than that of SiO2 aerogels (0.175 W/m·K).