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The corrosion resistance of carbon-carbon composite materials (C–C composites) was studied in a corrosive media of coolant NaF+ZrF4 salt (a model heat-transfer) at 700 °С in the air flow. It has been shown that C–C composite material is resistant to the model heat-transfer even under conditions of critical temperature accident. The main mechanism that leads to the C–C composite corrosion is a mechanism of composite material oxidation due to the contact with the air. The study has evidenced that the C–C composite burn-up rate well correlates with the pyrocarbon matrix content in the composite, the matrix content increase by 2530% results in the composite corrosion resistance increase by a factor of 2–4. So, by developing corrosion-resistant carbon-carbon composites one has a problem of finding an optimum fiber-matrix ratio in the composite. It has been confirmed experimentally that by silication of C–C composites with the use of the methods which were developed in NSC KIPT it is possible to increase the service life of products under simulated accident conditions by a factor of 7–7.5.

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The erosion factor of the matrix and filler phase composition having influence on the C-C composite resistance has been shown. The main mechanisms of such an effect are determined and the steps of improving the functional characteristics of composites are determined. It is assumed that the erosion and sublimation resistance of C-C composites, obtained by the gas-phase infiltration method using the radially-moving zone of pyrolysis, is due, first of all, to a highly-ordered crystalline pyrocarbon matrix. It is shown that the C-C composites have a unique temperature resistance and workability at high temperatures.