Oxidation Parameters of Oxide Dispersion Strengthened Steels in Supercritical Water

Abstract

The kinetic parameters of oxidation of two oxide dispersion strengthened (ODS) alloys, PM2000 and MA956, in supercritical water (SCW) are evaluated using an updated model that assumes that the growth of the outer layer is governed by the transport of interstitial cations through the inner layer. The model is able to reproduce quantitatively the depth profiles of individual constituent elements in the inner and outer layers, as well as in the diffusion/transition layer of the alloy between the inner layer and the bulk substrate. The rate constants and diffusion coefficients decrease with time, indicating oxide layer restructuring.