Abstract
The corrosive behavior of Alloy 625 in supercritical water at 700°C and 24.8MPa with dissolved oxygen contents of 150ppb, 1ppm, and 8.3ppm was studied. The oxides grown on all test samples exhibited a duplex-layer structure. The outer layer was composed of a spinel oxide Ni(Cr, Fe) 2 O 4 and the inner layer was mainly continuous Cr 2 O 3 . Ni-containing oxides, such as spinel Ni(Cr, Fe) 2 O 4 , did not form on samples exposed to the supercritical water environment containing 150ppb dissolved oxygen. Oxygen content might considerably affect the composition and structure of oxides grown in supercritical water for Alloy 625. © 2013 Elsevier Ltd.