Multi-phase SiZrOC nanofibers with outstanding flexibility and stability for thermal insulation up to 1400 °C

Ceramic fibers are one of the most important high-temperature thermal insulating materials for application in the harsh environment. However, the practical use of traditional ceramic fibers has been largely impeded by their poor thermal stability or high thermal conductivity at high-temperatures. Here, multi-phase SiZrOC (SiO x C y , SiO 2 , ZrO 2 , ZrSiO 4 and C) nanofiber (NF) was rationally designed and prepared according to the intrinsic factors of these phases with lower heat transfer effects (significant phonon scattering and infrared shielding) that contributes to the high-temperature thermal insulation performance in ceramic fibers. Owing to the unique multi-phase microstructure, the obtained SiZrOC NFs exhibit ultralow thermal conductivity (~0.043 W m −1 K −1 at 25 °C and ~0. 233 W m −1 K −1 at 1400 °C), high flexibility, good mechanical strength, excellent fire resistance and thermal stability even up to 1400 °C, which makes it an ideal high-temperature thermal insulator especially for applications under extreme conditions. This work not only presents with the fabrication of a prosperous material for high-temperature thermal insulation but also offers a novel strategy for developing a wider range of high-temperature thermal insulating materials.