MODEL CONCEPTS OF THE MECHANISM AND KINETICS OF HIGH-TEMPERATURE OXIDATION OF CARBON-BASED COMPOSITES IN OXYGEN-CONTAINING GAS ATMOSPHERES

A model and basic theoretical concepts of the high-temperature oxidati on of carbon-based composites in oxygen-containing gas atmospheres are developed. The higher the heat resistance of an impregnating metal or alloy, the higher the heat resistance of the composite obtained shoul d be, provided that the oxide film covers the entire metal surface and the temperature is kept lower than the melting point and temperature of intense sublimation of the metal oxides formed. When a new, more pr otective oxide layer is formed, the oxidation rate can decrease substa ntially, and the composite can become passivated provided that the tem perature or oxidant pressure exceeds its critical value. These stateme nts are confirmed by the experimental data.