Preparation and structure of silicon oxycarbide aerogels fabricated by polymer derived ceramics method

SiOC ceramic aerogels (SiOC CAs) were successfully fabricated through vacuum freeze-drying method combined with PDC process. The microstructure, phase composition and thermal conductivity of the as-prepared samples were systematically investigated. The results showed that the as-prepared SiOC CAs were composed of amorphous phase with three-dimensional network porous structure. In addition, the as-prepared SiOC CAs demonstrated high specific surface area of 635.72 m 2 /g, low density of 0.19 g/cm 3 , large pore volume of 0.49 cm 3 /g, and ultra-low thermal conductivity of 0.031 ± 0.0015 W/(m K). The present developed work provided a new thought to produce other porous Si-based ceramic aerogel materials.