Corrosion Behavior of Austenitic AL-6XN Stainless Steel in Supercritical Water

The corrosion behavior of AL-6XN stainless steel in supercritical water at 550 ℃,600 ℃ and 650 ℃ was investigated.Morphology,structure and elemental distribution of the oxide film were investigated by SEM,EDS and XRD.The results show that the oxide growth of AL-6XN stainless steel in supercritical water is believed to follow the solid-state growth mechanism,and the weight gained at 600 ℃ were approximately three times of that at 550 ℃,while the weight gained at 650 ℃ reduced drastically.Granular corrosion products with Fe-rich magnetite structure were observed on the surface,and the oxide scale exhibited a dual-layer structure and mainly consisted of an outer Fe3O4 structure and an inner FeCr2O4/(Ni,Fe)Fe2O4 mixed spinel structure.