Corrosion modelling of austenitic steel in molten sulphate deposit

A new explanation of a corrosion test of austenitic steel AISI 316 by Hendry and Lees is presented. A mechanism controlled by the complex alkali iron trisulphate formation reaction is proposed. An attempt has been made to evaluate the equilibrium constant and the rate coefficient of the controlling reaction on basis of the Hendry and Lees experiment. The model describes quantitatively the rate of steel sample corrosion in molten sulphates at 600 °C and its slow down to almost zero as a consequence of the chemical equilibrium state instead of resolidification of the molten sulphates solution.