Study on Inhibition of N80 Carbon Steel in 0.5M KCl Solution Saturated with CO2 by Gum Arabic

The effect of Gum Arabic (GA) on the corrosion of an N80 carbon steel pipeline in a CO2 -saturated chloride (0.5M KCl) solution was investigated through AC impedance and polarization curves. Potentiodynamic measurements showed that the corrosion current density decreased in the presence of inhibitors and that the inhibitor acts like a mixed-type inhibitor, with anodic predominance. The Nyquist diagrams showed an increase in polarization resistance values in the presence of the inhibitor, thus increasing inhibition efficiency. At higher temperatures, the inhibition efficiency decreased, implying that the inhibition action of GA occurred via the physical adsorption process. The activation parameters of the corrosion process such as activation energies, Ea, and the heat of adsorption, Qads, were calculated, respectively, by the obtained corrosion rate and inhibition efficiency at different temperatures. At higher temperatures, the increase in activation energy combined with the negative levels of the heat of adsorption further supported the physical adsorption nature of the process.