The oxidation behaviour of an austenitic steel in deaerated supercritical water at 600–700 °C.

Oxidation tests were conducted on austenitic steel exposed to deaerated supercritical water at 600–700 °C and 25 MPa. The oxidation kinetics followed between a linear law and a parabolic law at 600–650 °C while followed a near-parabolic law at 700 °C. A double oxide layer, which consists of a Fe-rich outer layer and a Cr-rich inner layer, was formed on the steel. The outer layer consists of Fe 3 O 4 at 600–620 °C for 1000 h and at 650–700 °C for 400 h, while the inner layer consists of spinel in all cases. Fe 2 O 3 is formed at 650 °C for 1000 h and at 700 °C for 600 h. Exfoliations were observed at 700 °C. The formation and spallation mechanism of oxides are also discussed. [ABSTRACT FROM AUTHOR]