Influence of pressure on the oxidation resistance of carbon fiber reinforced ZrB2/SiC composites at 2000 and 2200 °C

Abstract The influence of pressure on the oxidation resistance of C-ZrB2/SiC composites was studied. Materials were tested in air at 2000-2200 °C at 1-900 mbar. SEM analysis on the tested samples revealed the formation of an outer compact layer of ZrO2 and an intermediate layer of ZrO2-SiO2 as well as a porous interface layer of ZrO2. SiC increase was beneficial up to 1650 °C, then the trend was inverted. At 1 mbar all samples were visibly less damaged and displayed similar performance both at 2000 and 2200 °C, indicating that oxidation resistance is mostly dominated by fiber consumption, which is more severe at ambient pressure.