Abstract: The oxidation resistance of 3D C C composites consisting of woven layers of orthogonal fibers in XY plane pierced by fibers in the Z direction at temperatures up to 3000℃ has been investigated. Scanning electron microscopy and X ray photoelectron spectroscopy were used to describe the reactivity of carbon carbon composites. The oxidation mechanism and the influence of microstructure on the reactivity of composites were discussed. The thermochemical ablation was simulated by direct passage of electrical current through the sample in the vacuum. The results show that the oxidation of the C C composites at ultra high temperatures is a non equilibrium process. Generally, the oxidation process is controlled by both gas phase diffusion and reaction kinetics at high temperatures, but only by gas phase diffusion at ultra high temperatures because of the CO CO 2 gas phase layer on the surface of the sample.

Key words: Tcarbon-carbon composites, oxidation resistance, microst ructure