Quantitative evaluation of the oxidation behavior of ZrB2-15 vol.%SiC at a low oxygen partial pressure

Oxidation tests of ZrB2–SiC composite were carried out at 1373–1923 K under a low oxygen partial pressure of 57 Pa. By making composite with SiC, ZrB2 shows good oxidation resistance. The ZrB2-15 vol.%SiC composite shows better oxidation resistance at higher temperatures than ZrB2-30 vol.%SiC with respect to mass decrease. The SiC depleting is the main cause of this mass decrease and is quite significant under the low oxygen partial pressure. The SiC depleting seems to start to occur at around 1673 K or higher. The mass changes of ZrB2-15 vol.%SiC are quantitatively discussed by introducing an empirical equation. A first attempt of the evaluation of passive/active transition has been conducted using the obtained values.