Oxidation behavior of an 11Cr ferritic-martensitic steel after Ar-ions irradiation in supercritical water

Corrosion behavior of an 11Cr ferritic-martensitic steel before and after surface modification by Ar-ions irradiation in supercritical water (SCW) at 823 K (550 °C)/25 MPa with different exposure times was investigated to understand the influence of irradiation on corrosion resistance of the steel in SCW. The spallation of oxide layer occurred in the region with Ar-ions irradiation after exposed for 100 h. Corrosion morphology revealed a porous structure in the region without irradiation. Filamentous MnCr2O4 oxides were observed in the oxide layer spalling region with a low radiation intensity corresponding to a dose of about 5.65 dpa. Many nano-sized oxides were observed in the oxide layer spalling region with a high radiation intensity corresponding to a dose of 10 dpa. Oxide size was gradually increased over exposure times but grow rate increased slowly. The diameter of nano-sized oxides was only 200-300 nm after exposed for 1000 h.