Influence of Ar-ions irradiation on the oxidation behavior of ferritic-martensitic steel P92 in supercritical water

The corrosion behavior of ferritic-marensitic steel P92 with and without Ar-ions irradiation in supercritical water at 823 K(550 degrees C)/25 MPa for different exposure times was investigated by a variety of characterization techniques. A distinct difference in oxidation morphology between irradiated and unirradiated samples was observed. The oxide morphology of samples with a relatively moderate radiation intensity was similar with that of samples without irradiation. Many small oxide particles were observed in the region with a relatively high radiation intensity but their size was increased gradually with increasing exposure times. Exfoliation of oxide layer occurred for irradiated samples exposed for 100 h. Chromium- rich oxide layer with a chromium content of more than 20 wt pct along with a small-scale three-layer oxide structures were observed in Ar-ions irradiated samples, arising from the microstructural change in steel samples after the irradiation. Mechanism for the exfoliation of oxide layer is also discussed. (C) 2014 Elsevier B.V. All rights reserved.