Abstract
Corrosion of pure iron in steam, distilled water and alkaline solutions at temperatures of 310-350°C was studied by the weighing method. Sheet specimens were placed both in the liquid phase and in the vapor phase. The amount of iron dissolved into the liquid and that of iron oxides formed on the specimen were determined separately.
Oxygen content in the corrosion system largely affected the rate and the appearance of corroded specimens. Corrosion in the liquid phase was parabolic and the corroded surface was smooth. The transition from parabolic to linear was found for specimens in the vapor phase over alkaline solutions.
The parabolic dissolution of iron and almost constant ratio of (dissolved Fe/total Fe corroded) through reaction for specimens in the liquid phase suggest that the competing reactions between oxide growth and dissolution take place at the oxide/liquid interface. The rate transition from parabolic to linear for specimens in the vapor phase is not fully explained by Haycock's model.
