Abstract: A series of 3D-C/SiC composites with different pyrolytic carbon (PyC) interfacial layers (about 20～300 nm thick) were prepared by chemical vapor infiltration. Simulation experiments at different temperatures were performed by exposing C/SiC specimens in single and coupling gases partial pressure atmospheres, namely, O2, H2O vapor and molten salt (Na+) vapor. It suggested that at intermediate temperature range (about 600～800℃) a dramatic effect of PyC thickness on the weight and strength change of C/SiC was shown, which was mainly influenced by O2 partial pressure, at high temperature range (about 1200～1300℃) the effect was not obvious relatively, which might be influenced by H2O vapor partial pressure, and finally at very high temperature range (>1500℃) the molten salt vapor was the factor of most possibility affecting the weight change of C/SiC.

Key words: C/SiC, Interfacial layer, Simulation experiment