Oxidation behaviour of Al2O3–TiC–Co composites at 800–1000 °C in air

The oxidation behaviour of nanometre and micrometre sized Al2O3–TiC–Co composites is investigated at 800–1000 °C in air for 25 h. The oxidation resistance of nanometre sized samples is better than of micrometre sized. Phase compositions and microstructures were studied by XRD and SEM. The values of general rate constant k and oxidation exponent n are dependent on oxidation temperature and composites. The oxidation kinetics followed a rate that is slightly faster than the parabolic-rate law at 800–1000 °C. The activation energy of the nanometre sized is higher than of micrometre sized in the range of 800–1000 °C.

Figure optionsDownload as PowerPoint slideHighlights
► The oxidation behaviour of Al2O3–TiC–Co composites is investigated at 800–1000 °C.
► The mechanism of oxidation has been discussed using kinetic considerations.
► The oxidation kinetics of the composites did not follow the parabolic-rate law.
► The rate is slightly faster than the parabolic-rate law at 800–1000 °C.