Pressure difference calculations for a protective coating consisting of oxidizing carbon-carbon material

Attention is drawn to the pressure increase in the pores of a carbon-carbon composite oxidizing in air at high temperatures. Estimates are obtained for the relative pressure difference between the coating-substrate interface and the outer medium in two limiting cases: for hydrodynamic and free-molecule flow regimes in the pores. The effect of the coating thickness, the ambient pressure and the temperature of the material on the relative pressure difference is investigated.