Synthesis of SiC whiskers via catalytic reaction method in self-bonded SiC composites

Catalyzed by in-situ formed Fe nanoparticles (NPs), 3C-SiC whiskers were prepared from expanded graphite and Si powders after firing at 1573 K for 3 h in Argon. The density functional theory calculations revealed that Fe catalysts facilitated the formation of SiC nucleus and the epitaxial growth of SiC whiskers via reducing the bonding strength in C=C dimer as well as Si-O and C-O bonds. Moreover, using SiC, expanded graphite and silicon powders as starting materials Fe-catalyzed self-bonded SiC composites were fabricated. Lots of SiC whiskers were synthesized in the as-prepared composites, leading to remarkable enhancements in high temperature mechanical behavior, oxidation resistance and cryolite resistance of the self-bonded SiC composites.