Oxidation model for construction materials in supercritical water-Estimation of kinetic and transport parameters

An upgraded model was employed to obtain estimates of kinetic parameters of oxidation of stainless steel Sanicro 28 (UNS N08028) and nickel-based alloy 690 (UNS N06690) in supercritical water at 650 °C/25 MPa up to 2000 h. In the present approach, it is assumed that the growth of the outer layer is governed by the transport of cations through the inner layer via an interstitialcy mechanism. The model is able to reproduce quantitatively the depth profiles of constituent elements oxide layer, as well as in the transition layer situated between the inner layer and the bulk alloy.