2ND-HARMONIC GENERATION AT SURFACES APPLIED TO CORROSION INHIBITION

Second harmonic generation (SHG) at surfaces is a laser spectroscopy capable of following the adsorption of a corrosion inhibitor on to a metal surface in situ with submonolayer sensitivity. In this work a commonly found generic active component of oilfield corrosion inhibitors, oleic imidazoline, on mild steel is studied. It is shown that SHG can follow the inhibitor film formation in both aqueous solution and white oil. Film persistency can be studied under turbulent flow conditions. Experiments on variants of oleic imidazoline show that ineffective corrosion inhibitors can be investigated and help elucidate the function of the various parts of the molecule. Finally it is shown that the competition between a commercial scale inhibitor and oleic imidazoline for a mild steel surface can be studied. The potential of SHG as a tool to study corrosion inhibitors for oil pipelines is discussed.