Application of scanning electrode techniques for the evaluation of iron–zinc corrosion in nearly neutral chloride solutions

Abstract

A model cut edge consisting of a zinc anode and a split iron cathode was used for studying corrosion mechanisms and assessing the suitability of scanning electrochemical techniques for corrosion studies at the microscale. Scanning electrochemical microscope (SECM), localized electrochemical impedance spectroscopy (LEIS) and scanning vibrating electrode technique coupled with the scanning ion-selective electrode technique (SVET/SIET) were applied. The corrosion products precipitated on the cathode once the critical pH and solubility limits were reached, which resulted from the diffusion of hydroxyl and zinc ions across the cathode. There was no evidence of self-healing by the corrosion products.