The corrosion process requires four key factors: an anode, a cathode an electrical connection,
and an electrolyte. Removing any one of these factors will effectively halt corrosion. Polymeric
coatings act as electrical insulators between the substrate and the electrolyte. The insulating
barrier blocks the exchange of ions therefore halting corrosion of the metal substrate.
Adhesion is critical to such a system. Good adhesion is achieved by a rough angular profile on
the substrate to allow the polymer to physically grip the substrate. Common standards require
at least a 3.0 mil (76 microns) angular profile and a NACE No. 2 /SSPC-SP 10 surface
cleanliness. Unfortunately, in the field, it is difficult to meet all these requirements. New
technology in polymeric materials has led to the development of epoxy-based products that
can be applied onto wet and oily surfaces, therefore easing some of the typical surface
preparation requirements. These materials are effective at displacing contaminants from the
substrate via a strong electronic affinity with the metallic substrate, thus allowing the epoxy to
penetrate the profile and create a strong mechanical bond.
Keywords: epoxy, coatings, surface, tolerant, underwater, contaminated, surface, polymer,
solvent, free, offshore, preparation, substrate, adhesion, profile