Corrosion behavior of austenitic 304NG stainless steel in supercritical water at 550 ℃/25 MPa

The corrosion behavior of 304NG stainless steel was investigated in supercritical water (SCW) at 550 ℃/25 MPa. SEM, EDS and XRD were used to analyze the corrosion morphology, structure and element distribution of oxide film. The experiment results show that 304NG stainless steel exhibits excellent corrosion resistance and its general corrosion rate is just 0.012 99 mg•dm^-2•h^-1 after exposure to SCW at 550 ℃/25 MPa for 1 000 h. A general and compact dual-layer oxide film structure with nodular corrosion is formed on 304NG stainless steel in SCW and its thickness is about 2.0 μm. The compact inner layer is rich in Cr and Ni, while the loose outer layer is rich in Fe.