Electrochemical Characterization of X60 Steel Corrosion at Different Overvoltages: A Cathodic Protection Study

Abstract

This paper presents an electrochemical characterization of X60 steel corrosion using polarization curves. In order to get a surface analysis, a Scanning Electron Microscopy (SEM) was used. Analyses by Energy Dispersive Spectroscopy (EDS) were done to characterize the corrosion products films formed on surface of the steel sample at the different overvoltages studied. The electrolyte was a synthetic soil solution and all electrochemical parameter was measured at room temperature, atmospheric pressure and 24 hours of the total exposure time. It is important to point out that these parameters were measured in the protection potential (versus saturated calomel electrode, SCE) and at different overvoltages. The results of the polarization curves show that the corrosion rate increased as the overvoltage also increased and this behaviour was corroborated by the superficial analysis obtained by SEM; where the corrosion morphology was localized and the aggresivity increased with the overvoltage. In addition, in all overvoltages, the anodic reaction was limited by a mass transfer process. A localized corrosion form was found in all tests.