Oxidation resistance and wettability of graphite/SiC composite

A graphite/SiC composite was synthesized at different calcination temperatures using microsilica and carboxymethylated cellulose. The oxidation resistance and wettability (with water) of graphite/SiC were investigated. The results showed that carboxymethylated cellulose could react with microsilica to form a coating of SiC on the surface of graphite at elevated temperatures. Consequently, SiO₂ phase was converted into SiC phase above 1 600 °C. The microstructure of the SiC coating on graphite became denser with the increase in temperature. Thermogravimetric curves revealed that the weight loss of graphite was approximately 97.3 wt.% whereas the value decreased to 29.78 wt.% when SiC was formed. Differential scanning calorimetry analysis showed that the SiC coating decreased the enthalpy of the carbon oxidation reaction from 12.02 kJ g⁻¹ to 1.14 kJ g⁻¹, confirming excellent oxidation resistance. Furthermore, the water contact angle of graphite was approximately 78.5° whereas that of the graphite/SiC composite was reduced to 43°. The study of the formation of graphite/SiC composite showed that SiO₂ could be reduced using carboxymethylated cellulose to SiO (g), which was deposited on the graphite to form SiC coating.