Durable Hybrid Coatings. Annual Performance Report (2008)

Abstract : The overall goal of this program is to contribute to the development of the next-generation anti-corrosion and other protective coating systems for USAF aircraft. The initial emphasis was on improvements in NDSU's promising Mg-based primer, which NDSU recently licensed to the major international aircraft coatings manufacturer. Work continued over the last year on improvements in primer binder, additions to NDSU's world-class high-throughput (HT) research and development capabilities that are necessary to work with this class of coatings, and meeting additional Air Force protective coatings needs such as hard surface pretreatments to work with the binder, and development of a methodology for depot-based repair indium tin oxide aircraft canopy coatings. Progress on all areas was made over the last year, as described in papers appended to this report. A significant new effort was initiated in prognostic measurement techniques to monitor the effectiveness of the magnesium-based primers previously developed. Accomplishments over the last year included development of an embedded sensor for monitoring corrosion of metallic primers based on Mg and Mg alloys in aircraft coating systems. Research on in situ monitoring of primer degradation involves the application of an embedded sensor within the coating system followed by polling the system using various electrochemical techniques while subjecting it to ASTM standard corrosion tests, namely B117 salt fog and Prohesion. The feasibility and effectiveness of the embedded sensor electrode have been investigated. It has been demonstrated that the two-electrode sensor assembly produces consistent and reliable electrochemical data for both ex situ and in situ environments, and the data are in agreement with control experiments carried out using the conventional three-electrode electrochemical cell configuration.