Fundamental Behavior of Model Corrosion Inhibitors

Abstract

Corrosion inhibition is a complex process of great economic importance that has been addressed in both empirical tests in industry and more detailed experiments in academia. Organic corrosion inhibitors are based on surface‐active compounds, which have been investigated thoroughly in colloid and surface science. In this review, the intention is to connect the physicochemical properties of surfactants to their corrosion‐inhibiting performance. The importance of adequate packing of corrosion inhibitors at the metal surface, as well as how the packing can be improved by co surfactants, is adressed. An investigation of the adsorption of corrosion inhibitor to the oil/water interface showed that the interface is capable of consuming considerable amounts of inhibitor when emulsified. The combination of cationic polymers and anionic surfactant proved to adsorb as a well‐covering film, highly efficient in reducing the corrosion rate. The results are most interesting since it shows that a higher inhibiting efficiency can be achieved even at moderate added amounts of these polymers. This is beneficial from both an economic and environmental point of view.

Keywords:

• Corrosion inhibition
• ionic surfactant
• cationic polymer
• adsorption
• corrosion rate
• corrosion potential
• critical micelle concentration
• quartz crystal microbalance
• Langmuir film
• linear polarization resistance

Acknowledgments

The work was a part of a joint project between the Institute for Energy Technology and the Norwegian University of Science and Technology, sponsored by the Research Council of Norway (146514/I30) and Clariant, ConocoPhillips, ENI Agip, M‐I Production Chemicals, Nalco, Norsk Hydro, Saudi Aramco, Statoil, and Total.