Synthesis of Mesoporous Carbon-Bonded TiC/SiC Composites by Direct Carbothermal Reduction of Sol-Gel Derived Monolithic Precursor.

Mesosporous carbon-bonded titanium-carbide/silicon-carbide ( C-TiC/SiC) ceramics with a high specific surface area (221 m²/g), ultra fine grains (10-50 nm), and high crystallinity were synthesized from direct carbothermal reduction (1100°-1450°C) of monolithic Ti-Si-O-C precursors made from controlled sol-gel process. The nano-sized carbide grains are bonded into bulk materials by poly(furfuryl alcohol) ( PFA) derived nanocrystalline carbon framework by 'bridge,' 'entanglement,' and 'adhesive' effects. Graphenes were found to grow on {111} planes of TiC grains but this was not observed for SiC. The bonding of graphitic carbon layers on carbide grains support the nanostructure and also result in the desired combination of functional and mechanical properties. [ABSTRACT FROM AUTHOR]