Lightweight and Strong Ceramic Network with Exceptional Damage Tolerance

Lightweight materials such as porous ceramics have attracted increasing attention for applications in energy conservation, aerospace and automobile industries. However, porous ceramics are usually weak and brittle; in particular, tiny defects could cause catastrophic failure, which affects their reliability and limits the potential use greatly. Here we report a SiC/SiO₂ nanowire network constructed from numerous well-bonded SiC nanowires coated by a biphasic structure consisting of amorphous SiO₂ and nanocrystal SiC. The as-obtained SiC/SiO₂ nanowire network is lightweight (360 ± 10 mg cm^-3), mechanically strong (compressive strength of 16 MPa), and damage-tolerant. The high strength of the network is attributed to the biphasic mixed structure of the binding coating which can restrict the deformation of nanowires upon compression. The lightweight and strong SiC/SiO₂ nanowire network shows potential for engineering applications in harsh environments.