Corrosion behavior of ferritic-martensitic steel P92 in supercritical water

The corrosion behavior of ferritic-martensitic (F-M) steel P92 exposed to static supercritical water (SCW) at 400-600℃ and 25MPa for 500h was investigated. The microstructures of oxide scale were analyzed by means of SEM, EDX and XRD, and the corrosion rules for P92 in SCW were also analyzed. The results show that the temperature has a significant influence on the corrosion rate, and corrosion mass gain at 600 and 500℃ is 5.32 and 1.59 times of that at 400℃; the oxidation kinetics curves of P92 follow parabolic law in 400-500℃, and follow near-cubic rate law in 600℃; a dual-layered oxide scale is composed of an iron-rich columnar magnetite (Fe3O4) in outer oxide layer and a chromium-rich magnetite/spinel-mixed (Fe3O4/FeCr2O4) in inner layer.