Oxidation behavior of ZrB2-SiC-ZrC in oxygen-hydrogen torch environment

The oxidation behavior of four ZrB2-SiC-ZrC compositions with varying ZrC contents (20, 34, 50, and 64 vol.%) was compared to that of ZrB2-SiC. The ceramics were oxidized at 1700 degrees C in an oxygen-hydrogen torch environment. The liquid oxide on the ZrB2-SiC sample came off from the surface under such an environment. In contrast, the all ZrB2-SiC-ZrC samples maintained the convex oxide on the surface, which consisted of ZrO2 and SiO2. The convex oxide of ZSZ with higher ZrC content was thicker, with the exception of ZrB2-SiC-64vol.%ZrC sample. The ZrB2-SiC-64vo1.%ZrC sample formed a ZrO2-rich layer, which was clearly denser than the ZrO2-SiO2. This densification was caused by ZrO2-sintering, and it was specific behavior under the dynamic pressure.