Effect of Hydrogen Chloride on Corrosion Behaviour of Fe–Cr Alloys in Wet CO2 Gas at 650 °C

Abstract

Chlorine-induced high-temperature corrosion is a major problem for structural materials used in incinerators because of the release of hydrochloride during waste combustion. In this work, the effect of HCl additions (0.05 and 0.1 vol%) to a N2–10CO2–10H2O gas on the oxidation of binary ferritic Fe—(15, 20, 25 and 30 wt%) Cr alloys was investigated at 650 °C. The addition of HCl significantly increased the rate of weight gain during reaction. Thick multi-layered iron-rich oxide scales formed on Fe-15Cr in all gases. Increasing Cr content increased the tendency for Cr2O3 scale formation, leading to complete protection for Fe-25Cr in HCl-free gas, but a level of 30Cr was required in the presence of HCl. Mechanisms underlying the effect of chlorine on the critical Cr concentration required for protective chromia formation are explored.