Relationship between Corrosion Rate and Metal Oxide Solubility in Supercritical Water

Abstract The purpose of this study was to examine the effect of density and metal oxide solubility on corrosion behavior of metal coupons in supercritical HCl aqueous solutions at oxygen atmosphere. Corrosion experiments were conducted by exposure of Fe, Ni, and Cr coupons to supercritical water oxidation (SCWO) environment with a reactor made of titanium alloy (Ti6A15V) at 400 °C and 25 MPa, 30MPa, and 40 MPa. The corrosion rate of chromium was smaller than that of iron and nickel and these values were increased with an increase of density. The estimated solubilities with recently proposed model increased with increase in density. Iron oxide solubilities were the highest and Chromium oxide solubilities were the lowest among these metals.