Accurate Electrochemical Model for Accelerated Development of Anodic Metal-Rich Primers

The cost of corrosion for Navy and Marine Corps aircraft is approximately $2.6B per year with the majority of corrosion damage caused by galvanic corrosion. Traditional chromate primers, in addition to being environmental and health hazards, have not been effective in decreasing the corrosion cost and do not protect from galvanic corrosion. Recently developed metal-rich primers (MPRs) have been identified as promising replacements for chromate primers with the capacity to protect from galvanic corrosion. MRPs are highly customizable, however lack of understanding of the effects of the many tunable formulation/particle options on coating properties and corrosion protection has limited their development and use. An accurate electrochemical and generalizable coating model is needed to enable new and improved protective materials that are less costly to design and faster to transition to market. Luna proposes to develop a finite element method model in Phase I to focus on the electrochemical interactions of the MRP with a substrate by considering the galvanic throwing power of the MRP. It will be expanded in Phase II into a comprehensive coating modeling tool for Al-rich and Zn-rich primers that accounts for topcoat effects, degradation with time, defects, and presence of galvanic couples.