Critical factors affecting the high-temperature corrosion performance of iron aluminides

Iron aluminides are known to exhibit good-to-excellent corrosion resistance in a number of high-temperature environments. Under most conditions, this resistance derives from the establishment and maintenance of a sound and ad herent alumina layer. Consequently the performance of iron aluminides under different aggressive high-temperature can be related to fundamental factor s that affect the development, adhesion, and durability (lifetime) of prote ctive alumina. Overall corrosion resistance depends not only on thermodynam ic stability of the reaction product in a particular environment and its gr owth kinetics, hut also on scale integrity and morphology, the chemical and physical nature of the oxide-metal interface, alloy strength, and the spec ific composition of the iron aluminide. Despite the multiplicity of factors , a relatively simple lifetime prediction model based on aluminum consumpti on can be used to evaluate the influences of changes in material parameters and to determine approaches to improving high-temperature corrosion resist ance of iron aluminides. (C) 1998 Published by Elsevier Science S.A. All ri ghts reserved.