Since the invention of silicon oxide aerogels in 1931, ceramic aerogels are well known for their low density, high porosity, large surface area, and excellent thermal and chemical stability, showing promising potential to be used as high-temperature thermal insulators, catalyst supports, filters, lightweight structural materials, and hosts for functional materials for various applications.However, conventional ceramic aerogels are usually constructed by oxide ceramic (e.g., silica and alumina) nanoparticles, and their practical applications have always been limited by the brittle nature of ceramics and volume shrinkage at elevated temperature (e.g., 600 °C for silica aerogels and 1000 °C for alumina aerogels).The brittleness of ceramic materials is caused by its strong combination. If we want to improve its mechanical properties, we must work hard from the microstructure of the materials.
In order to solve the above problems, Prof. Wang Hongjie's research group prepared an ultra-light, compressible and high-temperature resistant ceramic aerogel by using the method of chemical vapor deposition and in-situ growth and self-assembly of silicon carbide ceramic nanowires. The macroscopic-assembled SiC NWA exhibits integrated properties of ultralow density (∼5 mgcm-3), large strain (>70%) recoverable compressibility, excellent fatigue resistance (1000 cycles with a set strain of 60%), energy dissipation performance (an energy loss coefficient of 0.40), refractory performance, high-temperature oxidation and heat resistance, thermal insulation (0.026 Wm-1K-1 at room temperature in N2), and high absorption capacity (130–237 g g–1) for organic solvents, all originating from the well-interconnected highly porous 3D nanowire architecture and superior mechanical and chemical nature of SiC nanowires.
The research results were recently published online in the international journal ACS Nano with the title "Ultralight, Recoverable, and High Temperature Resistant SiC Nanowire Aerogel" (impact factor: 13.942).Lei Su is the first author, Hongjie Wang is the corresponding author, Xi 'an Jiaotong University is the sole author unit and corresponding author unit.
The work was supported by the National Natural Science Foundation of China.
Literature link: https://pubs.acs.org/doi/10.1021/acsnano.7b08577