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

• The corrosion of FeCoNiCrMo high-entropy alloy was studied in CO 2 /CO gas mixture at 700 and 950 °C. • This high-entropy alloy experienced an exclusive oxidation in various CO 2 /CO mixed gases. • The oxidation rates steadily increased with increasing oxygen pressure and temperature. • TEM analyses confirmed that (Mn,Fe) 3 O 4 and MnO formed in the outer layer while (Mn,Cr) 3 O 4 and MnO developed in the inner layer at 950 °C. The corrosion behavior of an equimolar FeCoNiCrMn high-entropy alloy was studied in various combination of CO 2 /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) 3 O 4 , and (Mn,Cr) 3 O 4 , while the duplex scales formed at 950 °C consisted of an outer layer of (Mn,Fe) 3 O 4 and, MnO, and an inner layer of (Mn,Cr) 3 O 4 andMnO. [ABSTRACT FROM AUTHOR]