Pitting Corrosion Beneath Undamaged Coating

Pitting corrosion away from the scribe was observed on almost all panels of both controls, which have chromate conversion coatings, after the corrosion tests. Pitting 

Adhesion of the cathodic E-coat to the plasma polymer surfaces is an important parameter in the corrosion protection of A1 alloys. In general, the adhesion performance of E-coat applied to plasma polymers was found to be far superior to that of the control panels. A-Methylpyrrolidinone (NMP) paint delamination was not observed after 120 min for E-coat on plasma polymer surfaces as compared to a maximal time for complete delamination of 5 min for E-coat on chromate conversion coating [2B] CC/E panels. The adhesion performance of cathodic E-coat on the plasma polymer surfaces could not be differentiated by the conventional tape test (ASTM D3359-93B), since E-coat on all of the combinations 

CtjOj Type Oxide InhiUtor in CCC, but No inhibitor in paint 

Treatment Type Average Corrosion Area (cm ) Average Corrosion Width (mm) Average % Area of Kts 

The corrosion resistance of a coated metal sheet could be considered to be dependent on at least five factors [1-4]. These factors are as follows  

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