Effect of pre-oxidation of Fe3Al on its corrosion resistance in sulfur and chlorine contaminated syngas

Pre-oxidation treatment of Fe3Al alloy, a material used in high temperature gas filtration, is common practice to improve corrosion resistance. This work evaluates the various pre-oxidation procedures in terms of the quality of the protective layers formed, using microstructural analysis and corrosion tests. The effect of atmosphere on the oxidation kinetics at 950?degrees C and the oxide layer morphology was determined. The corrosion resistance of Fe3Al filters was investigated in simulated coal-derived synthesis gas in the temperature range 600800?degrees C. It was found that the corrosion resistance of Fe3Al was significantly improved by the development of the surface oxide layer, and that the quality of oxide layer is dependent on the oxidation treatment conditions, such partial oxygen pressure, pO2. The best corrosion resistance was achieved with a two-stage oxidation treatment, involving initial pre-oxidation at low pO2 and final pre-oxidation at high pO2. (c) 2011 Curtin University of Technology and John Wiley & Sons, Ltd.