Change of properties after oxidation of IG-11 graphite by air and CO2 gas

Artificial graphite is typically manufactured by carbonization of a shaped body of a kneaded mixture using granular cokes as a filler and pitch as a binder. It undergoes a pitch impregnation process if necessary and finally applying graphitization heat treatment. The effect of thermal oxidation in air or a CO2 atmosphere on IG-11 graphite samples is investigated in this study. The results show a localized oxidation process that progressively reveals the large coke particles with increasing level of overall weight loss in air. The surface of the graphite was peeled off and no change was found in the specific gravity after air oxidation. However, the specific gravity of graphite was continuously decreased by CO2 oxidation. The decrease in the specific gravity by CO2 oxidation was due to CO2 gas that progressed from the surface to the interior. The pore shape after CO2 oxidation differed from that under air oxidation.