Catalyst-free hybridization of silicon carbide whiskers and expanded graphite by vapor deposition method

A simple approach was developed to hybridize silicon carbide (SiC) whiskers on graphitic layers in expanded graphite (EG) by silicon vapor deposition without catalyst. The synthesis of EG/SiC composite was carried out above 1000 °C in an enclosed crucible where the EG was placed above the silicon powders. The vapor–solid (VS) mechanism is the predominant one for the growth of SiC whiskers. Namely, Si (g) vapor derived from silicon powder at high temperatures deposits on the active carbon atoms locating at the edge and layer of EG to form the SiC nuclei. Subsequently, SiC whiskers grow up with a continuous deposition of Si (g) vapor on the SiC nuclei. The partial pressure of Si (g) vapor is favored with the increasing firing temperature, which promotes the growth and coarsening of SiC whiskers on EG.