Computer simulation of single pit propagation in stainless steel under potentiostatic control

A model is proposed for the propagation of corrosion pits in stainless stee l under potentiostatic conditions. The model is based on the requirement of a near-saturated local chemistry in the pit and uses an equation previousl y formulated for the anodic dissolution kinetics in this environment. Salt film precipitation, electrolytic migration, and transport outside the pit a re each considered explicitly. Numerical simulations of pit growth have rep roduced the experimentally observed characteristics of pitting. including d evelopment of a pit cover, spontaneous repassivation of metastable pits. in creased stability at higher applied potentials. and a tendency for pits to become dish-shaped rather than hemispherical. (C) 2001 The Electrochemical Society.