Performance evaluation of an imidazoline corrosion inhibitor in a CO2-saturated environment with emphasis on localised corrosion

The ability of an imidazoline inhibitor to provide corrosion protection to X65 carbon steel in a CO2-saturated sodium chloride (NaCl) solution at 80 degrees C was evaluated. The performance of the inhibitor was investigated with respect to both generalised and localised corrosion behaviour using in-situ electrochemical measurements, ex-situ scanning electron microscopy (SEM) and non-contact surface profilometry. We demonstrate that the optimum inhibitor concentration required to minimise generalised corrosion is significantly lower than that required to minimise localised corrosion. This highlights the importance of systematic, post-test topographical measurements in the selection and optimisation of inhibitor dosage.