Mechanism of growth, composition and structure of oxide films formed on ferrous alloys in molten salt electrolytes—a review

The growth kinetics, chemical composition and structure of scales formed during corrosion of Fe and its alloys in molten salts are reviewed. Special attention is paid to the effect of the composition of the molten salt mixture and the gas atmosphere on the stability and protective ability of corrosion layers. First, the thermodynamical background of the corrosion and oxidation of Fe-base engineering materials in molten salt media is briefly commented. A concise review of the growth kinetics of passivating oxide films is also presented. These two introductory chapters serve as a guide for the extensive survey of the growth mechanism, nature and properties of oxide and related scales on ferrous alloys in a range of molten electrolytes—chlorides, nitrates, sulphates, carbonates, hydroxides and mixtures thereof in gas atmospheres containing O2, CO2, SO2, SO3 and HCl.