Corrosion tests of ferritic steel and ferritic-martensitic steel were carried out in supercritical carbon dioxide at 550-600 degrees C under 15 MPa. The oxidation kinetics follows near-cubic law in all cases. Ferritic-martensitic steel P92 exhibited better corrosion resistance than ferritic steel T22, but oxide scale formed on ferritic-martensitic steel P92 is apt to spalling at 600 degrees C. The phase analysis shows that only the magnetite and spinel phases are identified. The cracking and spalling behavior of the oxide film in supercritical carbon dioxide was studied. Furthermore, the comparison of the oxidation rate of T22 and P92 in supercritical carbon dioxide and supercritical water is investigated in this paper. The influence of temperature on the microstructure of oxide scale is discussed. (C) 2019 Elsevier Ltd. All rights reserved.