Measure of the driving forces of underfilm differential contamination cells and differential aeration cells

Specially designed multilaminar electrochemical sensors (MS) are used to determine the difference in potential between the local anodes and cathodes of corrosion cells that form under protective organic coatings. These MS not only allow quantification of the effect of underfilm contamination and differential aeration on corrosion kinetics but also supply valuable information for a better understanding of the corrosion process mechanism. The use of MS with alternately clean and contaminated laminae clearly shows that differential contamination cells are capable of generating potential differences (driving forces) of hundreds of millivolt, as also occurred with underfilm differential aeration cells.