Thermally stable low-shrinkage monolithic SiC aerogels for heat insulation

In recent years, SiC aerogels have attracted considerable research interest owing to their excellent high-temperature resistance. It is crucial to research and improve the thermal stability of SiC aerogels under long and multiple heat treatments. Herein, we develop a series of monolithic SiC aerogels with a density of 0.23–0.28 g cm⁻³, low-thermal linear shrinkage of 21%–27 %, and high compressive strength of 0.38–0.60 MPa by designing a novel core–net structure. The resulting aerogels exhibit excellent thermal insulation thermostability and high-temperature reusability. Thermal conductivities of 0.0455–0.0678 W K⁻¹ m⁻¹ and 0.0934–0.1313 W K⁻¹ m⁻¹ were achieved at 40 °C and 900 °C, respectively. Following three consecutive heat treatments using a butane spray gun for 2000 s, the macromorphology exhibited no change, and the backside temperature was 230 °C. The results demonstrate an effective solution to reuse aerogels as long-lasting high-temperature insulation materials.