OXIDATION BEHAVIOR OF C/C-SIC COMPOSITES WITH VARIED MATRIX COMPOSITION

Because of the excellent thermal stability and mechanical properties, carbon fiber reinforced ceramics, C/C-SiC composites, have a sound potential for a variety of high-temperature applications. However, the thermal stability in oxidative environment is strongly dependent on the microstructure and phase composition of the matrix. For investigating the influence of matrix composition on the oxidation behavior of C/C-SiC composites, the C/C-SiC composites with varied matrix composition were exposed in air at elevated temperatures. The oxidation behavior was evaluated by the mass change and microstructure analysis as a function of exposure time and temperature. Results revealed that the different oxidation mechanisms are responsible for the oxidation kinetics of composites exposed at different temperatures. At high temperature regime, the difference in oxidation behavior for composites with different matrix composition becomes pronounced. The strong oxidation resistance could be attributed to the high mass fraction of SiC matrix and its homogeneous distribution in composites.