Enhancing the Performance of Pulsed Current Applied Coatings for Corrosion Protection

Accelerated Low Water Corrosion (ALWC) is a recently identified form of microbiologically induced, aggressive, localised corrosion. It leads to rapid deterioration of maritime steel structures (such as steel-piled retaining walls at docks and harbours), it has required early and expensive remedial works and, where left un-repaired, it has resulted in catastrophic failure. It is distinctive from other types of marine corrosion both in its location, occurrence and, in particular, its rate of attack. As implied in its description, ALWC occurs close to the level of the lowest astronomical tide (LAT). It is thus relatively difficult to locate and identify on routine visual inspection. Although the phenomenon of ALWC has probably always been present in the environment, there is a clear perception by asset owners that its incidence and severity have increased significantly in the last 20-30 years. The research described in this proposal is a focussed mechanistic study on a potential method for remediation and protection from ALWC using a cost-effective 3-stage, environmentally benign process that involves:surface cleaning and removal of deposits, surface sterilisation for local microbial control, followed by the formation of a protective calcareous film.