Employing Electrochemical Impedance in Predicting Corrosion Events

By Tony Gichuhi, Andrew Balgeman, Shonda Prince, Caitlin Wagner, Shannon O’Brien, Amanda Adams

In 1990, the federal highway authority gave the I-35W Mississippi River Bridge a rating of “structurally deficient,” citing signifi can’t corrosion in its bearings. The need for better screening and detection of corrosion in our infrastructure was heightened by the collapse of this bridge in Minneapolis in 2007. Predicting corrosion events or coating failures and pitfalls can be done using non-invasive electrochemical techniques such as electrochemical impedance spectroscopy (EIS).

In this article, EIS is used to monitor the performance of direct-to-metal (DTM) coatings on steel over a period of time. The authors also attempt to correlate EIS spectral responses to well known accelerated techniques such as ASTM B117 salt spray and Prohesion G85A5.