Effects of ZrB2 and SiC dual addition on the oxidation resistance of graphite at 1600–2000 °C

• The oxidation behaviour of C–ZrB2–SiC at 1600–2000 °C in air was investigated.
• The oxidation kinetics was characterized via in situ dimension monitoring.
• ZrB2 + SiC further improved the oxidation resistance of graphite compared to ZrB2.
• The passive/active oxidation of SiC determined the oxide scale microstructure.

The effects of ZrB2 and ZrB2 + SiC additions on the oxidation kinetics of graphite at 1600–2000 °C in air were investigated. The ZrB2 + SiC dual addition improves the oxidation resistance of graphite more effectively than the ZrB2 single addition, because the oxide scale formed on C–ZrB2–SiC is denser and thinner due to the existence of glassy SiO2. As the oxidation temperature increases, the oxidation rate of C–ZrB2–SiC gradually increases and oxide scales with layered microstructures form on its surface due to the greatly enhanced active oxidation of SiC at higher temperatures.