The effect of gas composition and contaminants on scale growth rates of FeCrAl alloys

Abstract

Fe–20Cr–5Al alloys were exposed to several environments crucial for industrial applications. Experiments in a simulated fuel-rich exhaust gas, in combustion gas, in air with additions of SO2 and HCl, and a N2–NO mixture were compared to the oxidation kinetics in air.While the addition of HCl and SO2 enhances oxide growth via increased spallation, the N2–NO mixture and the simulated exhaust gas seem to act as a shield gas due to the reduced oxygen partial pressure. As the local geometry can also change the gas composition during oxidation, e.g. inside crevices, results from an experiment with a deep bore are presented, simulating such a situation.