Organic inhibitors pipeline

It is seen that the organic molecule adsorbs on the Fe in the same way with respect to potential as on Pt, there being a shift in the potential of the maximum corresponding to the difference of the pzc for Pt and Fe. Thus, it is correct to consider inhibitor adsorption in pH 4 as occurring on the metal of the pipeline rather than on an oxide or carbonate coating. It is possible that some oxide or carbonate exists on the metal surface in these situations of pH 4 (C02 saturated), but that the corrosion and its inhibition occurs through cracks in the film, which expose bare Fe to the solution. 

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