The corrosion of an equimolar FeCoNiCrMn high-entropy alloy in various CO2/CO mixed gases at 700 and 950 °C

Abstract

The corrosion behavior of an equimolar FeCoNiCrMn high-entropy alloy was studied in various combination of CO2/COmixed gases at 700 and 950 °C, with the oxygen partial pressure range from 5.0 × 10−16 to 7.9 × 10−8 Pa. The alloy exclusively experienced oxidation, and its kinetics followed the parabolic rate law at both temperatures with the oxidation rates steadily increasing with oxygen pressure. This result demonstrated that a typical oxide scale exhibited a p-type semiconductivity. The scale formed on the alloy at 700 °C was thin, consisting of a mixture of MnO, (Mn,Fe)3O4, and (Mn,Cr)3O4, while the duplex scales formed at 950 °C consisted of an outer layer of (Mn,Fe)3O4 and, MnO, and an inner layer of (Mn,Cr)3O4 andMnO.