Inflection of backward sweep of cyclic polarization curve: Pit transition potential E_ptp

Abstract

The influences of ex‐situ applied load, scan circle, reverse potential, chloride concentration, and temperature on inflection (Eptp) of backward sweep of cyclic polarization of 7150 Al alloy were investigated. The 2nd derivative of polarization curves was used to accurately determine the value of Eptp. Eptp is determined as the potential where massive metastable pits finished their repassivation process during reverse scan, providing an insight into highly constricted forms of localized corrosion repassivation. Chloride ion and diffusion condition have predominant effects on this inflection. Eptp showed non‐monotonic trend with temperature and relevant discussion was given as well.