2001 W.R. Whitney Award Lecture: Understanding the Corrosion of Stainless Steel

TLDR: In this paper, the anodic kinetics of the metal in the already-developed microenvironment of a pit can account for the effects of a large number of variables in pitting corrosion.

Abstract: In order to predict corrosion damage on passive metals, it is essential to use statistical methods and semi-empirical models, but at the same time we must maintain active inquiry into the fundamental deterministic processes that occur during localized corrosion. If it were the case that atomistic events occurring within the intact passive film were responsible for, say, the beneficial effect of alloyed molybdenum, then we would have a gigantic job to do. Luckily, it appears that the quality of the passive film mainly affects the nucleation frequency of pits and has little or no bearing on the effects of environmental or metallurgical variables: T, Cl−, Br−, H2S; Mo, N, σ …. We find that the anodic kinetics of the metal in the already-developed microenvironment of a pit can account for the effects of a large number of variables in pitting corrosion. Specifically, above the critical pitting temperature (CPT), the potential required to precipitate an anodic salt film in a cavity of relevant size is ...