Effects of oxygen partial pressure and atomic oxygen on the microstructure of oxide scale of ZrB2-SiC composites at 1500 °C

The oxidation behaviour of ZrB2-20 vol.% SiC composites was investigated based on the microstructural evolution of oxide scale under different oxygen partial pressures at 1500 °C, and the similar experiment was performed in atomic oxygen for comparison. The thickness of the oxide scale increases first and then gradually decreases as the pressure decreases, which is strongly dependent on both total pressure and oxygen partial pressure. The atomic oxygen significantly enhances the oxidation of ZrB2-SiC composites, but has little effect on the microstructure of oxide scale. The oxidation mechanism of ZrB2-SiC composites is also discussed in detail.