Normally, stainless steels are utilized without any type of coating whatsoever. This report cites a few cases where coatings may be contemplated for use on stainless steels. Of particular interest is the use of various antifouling type coating systems applied over anticorrosion barrier coating systems for seawater service. Testing in natural seawater has demonstrated that coatings can protect susceptible stainless steel from barnacle related crevice corrosion and localized corrosion at weldments. However, coating defects and other unintentional or
intentional interfaces with bare metal may create new areas for crevice corrosion to initiate. The risk of serious crevice corrosion damage to the substrate increases with the amount of bare metal exposed. Test results
demonstrated that even a relatively small area of bare stainless steel is sufficient to support cathodic reactions that produce crevice corrosion penetrations in excess of 2 mm in less than six months. Even a 6% Mo alloy was susceptible. It was demonstrated that localized corrosion can be prevented by the use of cathodic protection from sacrificial zinc
anodes. However, the degree of polarization associated with zinc anodes contributed to blistering and disbonding of the coating in some cases. The current test program did not investigate protection afforded by
inorganic zinc-rich primers. Keywords: stainless steel, crevice corrosion, natural seawater, coatings, antifouling, ablative-Cu, elastomeric, epoxy, cathodic protection, zinc anodes