Influence of hydrogen in iron and in two stainless steels on aqueous and gaseous corrosion

The influence of hydrogen in Fe, 301 stainless steel (SS 301), and Avesta 353MA on corrosion resistance in aqueous solutions was studied. The oxidation kinetics of uncoated and Pt-coated Fe was also investigated in O-2 at 500 and 700degreesC. Electrochemical and weight loss measurements were used to evaluate the corrosion resistance in aqueous solutions, and the high-temperature oxidation rate was determined by measuring the pressure decrease in a closed volume. Observations of a high dissolution rate of Fe and SS 301 in deionized water, as well as a high oxidation rate in O-2, can be explained by an increased metal cation transport in the oxide film induced by hydrogen in the metal. However, hydrogen up to a certain concentration in Avesta 353MA was found to increase the resistance to localized corrosion in chloride solution. Pt coating on Fe was found to decrease the oxidation rate and improve scale adherence. The presented results are discussed in view of recent findings of balanced metal cation and oxygen anion transport in protective metal oxides. (C) 2002 The Electrochemical Society.