Breakdown of Passive Films on Metals

Explanation Based on Point Defect Model

Abstract

The Point Defect Model (PDM), proposed and developed by Macdonald and coworkers, is one of excellent models for growth and breakdown of passive films on metals. This review introduces a concent of passivity breakdown based on the PDM, and explains how the model deterministically derives passivity breakdown potential, induction time to passivity breakdown in detail. The review also introduces the recent two findings of dependence of passivity breakdown potentiasl on potential scan rate and probability distribution in induction time to passivity breakdown derived from the PDM. These theoretical expressions for passivity breakdown are reasonably verified in comparison with the experimental data for passivated Ni in borate buffer solutions with chloride ions.