Kinetics of SiC Formation on Graphite Using N-2-CO-SiO and N-2-CO-H-2-SiO Gas Mixtures

Abstract

The formation of SiC on a graphite surface through the reaction between SiO gas and C was investigated. Experiments were conducted at 1843K, 1873K, and 1903K (1570 degrees C, 1600 degrees C, and 1630 degrees C) under N-2-CO-SiO or N-2-CO-H-2-SiO gas mixture atmospheres. The formation rate of SiC on the graphite increased with the increasing temperature and with the decreasing partial pressure of CO gas. The forward (k(f)) and backward (k(b)) reaction rate constants of SiC formation with SiO gas were obtained as follows: ln k(f) (mol/cm(2) . s . atm ) = 29: 175 - 76, 083/T ln k(b) (mol/cm2 . s . atm) = 53.518 - 129, 072/T Under the N-2-CO-H-2-SiO gas mixture atmosphere, the formation rate of SiC on the graphite increased. It was observed that the formation of SiC whiskers was enhanced by the catalytic reaction in liquid Fe-based nanodroplets.