Finite-difference time-domain study of hollow Zirconium dioxide nanofibrous aerogel composite for thermal insulation under harsh environments

ZrO₂ fiber aerogels with robust mechanical strength, low density, and low thermal conductivity can be considered high-temperature thermal insulation materials. However, in harsh environments, both radiative thermal resistance and mechanical properties are hindered, resulting in high thermal conductivity and structural degradation. Here, inspired by weaved sisal sheath fiber and polar bear hairs, we proposed a novel hollow ZrO₂ nanofibrous aerogel composited with hollow SiC opacifiers (H–ZrO₂@H–SiC composite). The super-insulation performances of the aerogel composite were numerically predicted by coupling the 3-D Finite-Difference Time-Domain (FDTD) method with the Rosseland approximation. The low density ordered nanofiber networks improved the mechanical properties, and the opacifiers with low density suppressed the radiative heat transfer. It exhibits a low effective thermal conductivity of 0.020 W⋅m⁻¹⋅K⁻¹ at 1270 K and an outstanding mechanical property based on the prediction using Finite Element Method, making it a new candidate for thermal insulation in harsh environments.