Testing and Accelerated Aging of Conductive Antifouling Paints for Marine Applications

Marine hydrokinetic (MHK) device survivability is necessary to understand in order to develop the vast renewable wave and tidal energy resource. Antifouling coatings serve to ensure device longevity by preventing degradation associated with mollusk adhesives and general performance degradation due to hydrodynamic surface changes, clogged pinch points, and added drag. Coatings developed to serve the shipping industry are generally insufficient for MHK service due to finite biocide content, short service life, and operating condition requirements such as continuous movement at elevated speeds. Electrochemical antifouling methods have been shown to be effective in the prevention of fouling organism growth on objects submerged in seawater.[1] Service life has been provided in one study as 8 months with failure due to binder paint film degradation.[2] Appropriate selection of paint binder systems and rigid substrates may extend this time significantly. Degradation of the conductive pigment filler, in this work graphite, may also lead to performance loss and ultimately to system failure. The specific goal of the current work is to model the antifouling process at a charged graphite filled paint electrode and the degradation of system performance due to degradation of the graphite filler. Under accelerated aging conditions no significant degradation has been observed with simulated aging to 20 years of service life.