Influence of cobalt on the oxidation resistance of Al2O3–TiC composites at 800–1000 °C in air

• The oxidation resistance of Al2O3–TiC–Co is studied at 800–1000 °C in air for 25 h.
• The cobalt content has important effects on the oxidation resistance of Al2O3–TiC.
• The oxidation kinetics of Al2O3–TiC with different cobalt content was analyzed.
• The Al2O3–TiC–Co sintered at 1550 °C does not follow a parabolic-rate at 800–1000 °C.

The isothermal oxidation resistance of Al2O3–TiC composites with 3 wt.% and 5 wt.% cobalt is investigated at 800–1000 °C in air for 25 h. The oxidation resistance of Al2O3–TiC composites with 5 wt.% cobalt is better than that of ones with 3 wt.% cobalt. The general rate constant k and oxidation exponent n depend on the cobalt content and oxidation temperature. The oxidation kinetics of Al2O3–TiC composites with 3 wt.% and 5 wt.% cobalt both followed a rate that is slightly faster than the parabolic-rate law at 800–1000 °C. The activation energy of the Al2O3–TiC composites with 5 wt.% cobalt is larger than that of ones with 3 wt.% cobalt at 800–1000 °C.

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