On the theory of CO2 corrosion reactions - Investigating their interrelation with the corrosion products and API-X100 steel microstructure

This electrochemical research investigates the interrelation between the corrosion reactions, the growth and characteristics of the corrosion products, and the microstructures of simulated Heat-Affected Zones (HAZs) from API-X100 steel. In saline CO2-saturated solutions, the corrosion products suppress more the anodic dissolution than the cathodic reactions. The corrosion products of ferritic microstructures are thicker and of higher cathodic currents than those of acicular-ferritic and martensitic microstructures, which are intrinsically less reactive. The significances of chloride, iron oxides, and Fe3C with the growth and reactivity of the corrosion products were explored. Schematics depicting the open-circuit reactions were made from electrochemical impedance spectroscopy measurements. (C) 2014 Elsevier Ltd. All rights reserved.