Influence of the dissolved oxygen content on corrosion of the ferritic–martensitic steel P92 in supercritical water

The corrosion of the ferritic–martensitic steel P92 exposed to supercritical water at 550 °C under 25 MPa with the dissolved oxygen contents of 100, 300 and 2000 ppb was investigated. The results indicated that the weight gain increased with the dissolved oxygen content. The oxide scale with a typical dual-layered structure including a Fe-rich outer magnetite layer and a Cr-rich inner layer was formed on all samples in spite of different dissolved oxygen. Finally, the possible explanations for the influence of the dissolved oxygen content on the weight gain and exfoliation of oxide scale were given.

► The corrosion of P92 in supercritical water with different dissolved oxygen contents was investigated.
► The weight gain increases with the dissolved oxygen content.
► The high dissolved oxygen content easily leads to cracks and exfoliation of oxide scale.