The corrosion of FeCoNiAl-based medium- and high-entropy alloys in various ratios of CO2/CO gas mixture

Abstract

The corrosion behavior of equimolar FeCoNiAl medium-entropy and FeCoNiCrAl high-entropy alloys was studied at 950 degrees C in various ratios of CO2/CO 2 /CO gas mixture. The results showed that both alloys experienced pure oxidation, and their oxidation kinetics followed the parabolic-rate law, having the oxidation rate constants increased with increasing CO2/CO 2 /CO ratio. The scales formed on FeCoNiAl were triple-layered, consisting of an outer CoFe2O4 2 O 4 layer, an intermediate CoAl2O4 2 O 4 layer, and an inner alpha-Al2O3 2 O 3 layer, while an exclusive alpha-Al2O3 2 O 3 layer formed on FeCoNiCrAl.