Microstructural characteristics of oxide scales grown on stainless steel exposed to supercritical water

The microstructural characteristics of oxide scales grown on stainless steel (SS) exposed to supercritical water (SCW) have been investigated by means of transmission electron microscopy. The oxide scales were found to have a multi-layer structure with Ni enrichment at the oxide/matrix interface and were identified as (Fe,Cr)2O3/(Fe,Cr)3O4/Cr2O3/Ni-rich steel/SS from the outer to the inner layer. The growth mechanism of the multi-layer oxides in SCW is discussed.