Novel high‐temperature‐resistant Y ₂ SiO ₅ aerogel with ultralow thermal conductivity

Abstract A novel Y ₂ SiO ₅ ternary aerogel was prepared from tetraethoxysilane and yttrium chloride hexahydrate via the sol‐gel method followed by high‐temperature calcination. The effects of different calcination temperatures on the microstructure, mechanical and thermal stability of the Y ₂ SiO ₅ aerogels were investigated. The aerogels exhibited low densities of 0.33‐0.62 g/cm ³ , low thermal conductivities of 0.029‐0.05 W/(m·K), and a relatively high strength of 0.16‐56.47 MPa. Moreover, compared with the Al ₂ O ₃ –SiO ₂ aerogel, the Y ₂ SiO ₅ aerogel has higher thermal stability and more excellent high‐temperature insulation, which has potential applications as a thermal protection material in hypersonic vehicles.