ELECTROCHEMICAL AND PERFORMANCE TESTING OF NANO ENGINEERED-COATINGS BASED ON ANA PRESENCE WHEN EXPOSED TO CORROSIVE ENVIRONMENT

摘要

In order to characterize the electrochemical mechanism of a novel additive that can be incorporated into existing surface treatments, hybrid coatings with varying amounts of the silver nano additive (ANA) were characterized. Steel panels were coated with two different types of base material: fusion bonded epoxy and commercial PPG Amerlock 2 paint, with the ANA content increased from 0% to 50% by weight. The panels were exposed in 3.5% NaCl and characterized by using electrochemical impedance spectroscopy (EIS) and surface analysis. EIS shows the interfacial mechanism when the ANA concentration is modified, and the barrier effect demonstrates the water uptake process while the sacrificial or cathodic protection demonstrates the impedance stability with time. The increase in the ANA percentage does not induce any galvanized corrosion that influences the impedance and the mechanisms in the coatings. This work in progress presents the results for short term exposure period (60 days) and proposes the mechanisms based on electrochemical testing and surface analysis