Assessing coating degradation along a scribe in a ballast tank environment

This study evaluates the suitability of corrosion testing methods for analyzing the scribe performance of coated steel in environments resembling ballast tanks. While the fog/dry test effectively accelerates corrosion on bare steel, it falls short of replicating ballast tank conditions for coated scribed steel. It shows significant variability, which limits precise evaluation. A procedure previously developed at AMACORT, the AMACORT CIFD-01 test procedure, proves more reliable for scribe performance analysis, offering greater precision and repeatability.This study also explores the effects of surface cleanliness and roughness on coating performance using the fog/dry test method. Fog/dry testing is used as it is widely recognized and commonly applied, whereas the AMACORT CIF D-01 protocol requires significantly more handling. Increased salt contamination correlates with a greater mean creep, which becomes significant when PSPC15 standards are being exceeded. Regarding dust contamination and surface roughness deviations, no significant effects were observed, like those seen with increased salt contamination. A dust contamination increase contributes to performance degradation but not significantly, nor do surface roughness deviations. These findings underscore the importance of selecting appropriate test methods and maintaining adherence to surface cleanliness and roughness standards, in particular salt contamination, to ensure optimal coating performance and adhesion durability.