High-Temperature Oxidation of Carbon-Carbon Composite Materials in Air

Abstract

The features of high-temperature oxidation in air of different home produced carbon materials: pyrolytic carbon, carbon fibres and coatings, composite materials on their base have been analyzed. It has been determined that the rates of oxidation of carbon materials in air at temperatures of up to 800 °C can differ rather greatly which is conditioned by peculiarities of the technology of their production differences in porosity and density, degree of carbon graphitization in the samples, etc. In all cases the mechanism of oxidation is determined by the nature of carbon-carbon linkages. The low-temperature region (up to 800 °C) is kinetic in which the rate of surface reaction of oxygen with carbon is limiting. For the high -temperature region of the process the slight dependence of the rate on temperature is typical. In the event of presence of silicon-bearing protective coatings on the carbon materials the oxidation process depends on the mass transfer of oxygen and carbon through a barrier layer made of SiC and SiO2.