AFM study of the oxide film formed on dual phase Fe3Al-Fe3AlC intermetallics

The topography of the oxide film formed during initial stage of oxidation at 800 °C on the Fe3Al and Fe3AlC phases in an Fe-16Al-0.5C alloy was analyzed using atomic force microscopy. The oxide film formed on the carbide phase was found to be thicker than that on the matrix, and the difference in thickness between two layers was around 0.5 μm. This was related to the presence of low Al content in the Fe3AlC phase compared with that in the Fe3Al phase. Due to different rate of oxidation in Fe3Al and Fe3AlC phases, the Fe-16Al-0.5C alloy does not follow the parabolic rate behaviour.