Corrosion under disbonded coatings having cathodic protection

Corrosion under a disbonded coating can be a serious problem on pipelines under cathodic protection (CP) as CP current may not penetrate to the steel beneath the dishonded area. Pipe-to-soil potentials at the surface do not indicate conditions under disbonded coating. This article explains the corrosion mechanisms that occur beneath disboned coating and makes suggestions to prevent coating disbondment in new construction.