Corrosion Behavior of C-276 Alloy in Supercritical Water at 650 ℃/25 MPa

The corrosion behavior of nickelbase alloy Hastelloy C-276 was investigated in supercritical water (SCW) at 650 ℃/25 MPa. SEM, EDS, GIXRD and XPS were used to analyze the corrosion morphology, structure and element distribution of oxide film. The results show that the corrosion process of C-276 alloy at 650 ℃/25 MPa in SCW is mainly dissolution of Ni. Since it can not form a uniform and complete oxide film, the alloy in SCW is not well placed to corrosion resistance. The dual-layer oxide film structure which is formed on C-276 is rich in Cr but poor in Ni, Mo. The outer -layer consisting of loose and large grains Ni(OH)₂ and NiO agrees with dissolution and precipitation mechanism, while the growth of the Cr₂O₃ inner layer is the result of water through the porous oxides.