Inhibition on Carbon Steel Corrosion in Presence of Hydrocarbon

In this work the study of electrochemical behaviour of organic compounds as corrosion inhibitors is being done over a carbon steel AISI 1018 immersed in a corrosive synthetic environment (brine type NACE 1D196), in the absence and presence of hydrocarbon. The techniques used were the electrochemical Polarisation curves and electrochemical impedance spectroscopy. In the Polarisation curves, the presence of corrosion inhibitors in the system shows that increasing of the concentration affects both the anodic and the cathodic stages of the corrosion process, showing that the obtained currents are lower by increasing the concentration of the inhibitor. On the other hand the inhibitor efficiency decreases with the presence of hydrocarbon in different systems. Electrochemical impedance spectroscopy shows that steel has high activity in the environments studied, being more remarkable at low frequencies and in the presence of hydrocarbon since the spectra shows flattened semicircles, with low values of real impedance and inductive trends. This establishes that the interaction of ions in the solution with the metal, where adsorption processes are governing the corrosion mechanism, is favoured by the presence of hydrocarbon.