Study of effective thermal conductivity of a novel SiO₂ aerogel composite for high-temperature thermal insulation

A SiO₂ aerogel composite doped with novel spherical hollow carbon@SiC infrared opacifiers was proposed. Finite-Difference Time-Domain (FDTD) combined with the Rosseland approximation techniques were used to numerically calculate the radiative properties and thermal conductivity under a large temperature range of 300–1400 K. The obtained results demonstrate that the addition of a large hollow between carbon and SiC into the core-shell opacifier can suppress radiation heat transfer at high temperature without increasing the solid heat conduction and density of the composite. Furthermore, spectral transport approximation in relation to the isotropic property of the novel opacifier was established. The findings indicate that the composite can be used as a lightweight and efficient thermal insulation material at high temperature.