Intergranular corrosion in evolving media: Experiment and modeling by cellular automata

We investigate the impact of the oxidizing character of the nitric medium on the evolution of the intergranular corrosion of a stainless steel. In two different oxidizing conditions (“severe” and “soft”), the corroded surface of the steel reaches a different steady state: the oxide is thicker, the intergranular grooves are thinner and the surface area is larger in the “severe” conditions than in the “soft” ones. Then we investigate the effect of an alternative “severe then soft” corrosion sequence. We show that the system re-adapts to the “soft” conditions without memory effect from the previous “severe” ones.