Stochastic Models of Pitting Corrosion of Stainless Steels: I . Modeling of the Initiation and Growth of Pits at Constant Potential

Abstract

A stochastic model for pit initiation is developed, involving as parameters an initiation frequency for pit nuclei, a death probability for unstable pits, and a critical age which defines the transition between a stable and an unstable pit. Emphasis is placed on validating methods for data analysis to recover the parameters of the model from observed current‐time series. Such methods are developed and tested using data generated by computer simulation of the process. The expected induction time for stable pit initiation is derived. Results for the statistics of ensembles of current‐time transients are given. Methods of analysis of the spectral power density of the current, taking into account the nonstationary process of stable pit propagation, are considered.