High thermal insulation and high strength SiBCN@SiC double network ceramic composite aerogel

Silicon carbide (SiC) fiber materials prepared by precursor conversion method have attracted extensive attention in recent years due to their excellent high temperature resistance and thermal insulation properties. Herein, a novel SiBCN/SiC dual network ceramic composite aerogel with the three-dimensional (3D) porous SiC fiber network obtained by direct electrospinning as the first network and SiBCN aerogel as the second network was prepared by combining electrospinning with sol-gel technology and supercritical drying technology. The microstructure, phase composition, pore size distribution, compressive resistance, thermal insulation and related mechanisms of the 3D SiC fiber network and composite aerogel at different heat treatment temperatures were investigated in detail. The results show that the constructed double-network structure can make up for the heat transfer problem of a single SiC fiber network and further reduce its thermal conductivity, so that the prepared composite aerogel exhibits a lower thermal conductivity (∼0.0316 W m−1 K−1). In addition, the unique double network structure endows the composite aerogel with excellent compressive properties (2.56–2.89 MPa).