Oxidation behavior of polymer derived SiCO powders

Polymer derived SiCO ceramic powders were fabricated by pyrolysis of polycarbosilane precursor. The oxidation behaviors of these powders were studied by thermogravimetric analysis at the temperature range of 900-1400 °C. The oxidation parabolic constants at different temperatures were calculated. From these parabolic constants, the apparent activation energies for oxidation could also be obtained. These results indicated that SiCO powders have a close oxidation rate to that of pure silicon carbide. The crystallinity of SiCO ceramics and silica scales has little effect on the oxidation rates. The results also elucidated that the oxidation mechanism for amorphous and crystalline silica is the same.