Corrosion resistance of PM2000 ODS steel in high temperature supercritical carbon dioxide

Corrosion of PM2000 ODS steel in supercritical CO2 at 650 degrees C and 20 MPa for 3000 h was studied. The corrosion performance of the alloys was evaluated by weight change measurements, and the surface oxide scale was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. PM2000 ODS steel showed significantly better corrosion resistance compared to austenitic stainless steels and nickel based alloys tested in the same conditions. The high corrosion resistance is attributed to the formation of a dense and protective aluminum-rich oxide layer on the surface. The oxide layer thickness was only about 200 nm after 3000 h exposure.