Cooperative Stochastic Behavior in Localized Corrosion: I. Model

A stochastic model for localized corrosion is investigated both analytically and numerically. A feature of the model is that each metastable pitting event can influence subsequent events, although the influence of an individual event decays with time. The model describes an abrupt, cooperative transition from metastable to stable pitting, both under constant, e.g., potentiostatic conditions, and under conditions corresponding to an anodic scan. The model accounts for several commonly observed distributions in pitting parameters. Histograms for the induction times for transition to stable pitting and for stable pitting potentials are presented.