Doctor of Philosophy, University of Akron, 2016, Chemical Engineering

Several studies have been published describing the corrosion inhibition effectiveness of surfactant admixtures by measuring the ability of surfactant molecules to physically adsorb onto metal surfaces. However, the effects of these admixtures have not been previously studied on coated metal surfaces to determine their corrosion inhibition mechanism. While corrosion protective coatings isolate exposed metal surfaces by forming a barrier between a substrate and the electrolyte, their performance is highly dependent on their interaction with their immediate environment. During the winter season in Snowbelt areas where chloride roadway deicers are greatly employed, coated metal surfaces in vehicles are constantly exposed to harsh and changing environments making them susceptible to failure. In order to extend the service life of these exposed coated surfaces, additional treatment by surfactant admixtures is regarded as an effective corrosion prevention strategy. In this work, the corrosion mechanism of surfactant admixtures on coated metal panels is evaluated by understanding the interaction of the liquid-solid interface. Despite the numerous mechanisms of inhibition behavior, it is hypothesized in this study that the contributions from inhibition solution systems create a protective layer over substrates by the formation of multi layers from aggregation or adsorption of surfactants. Furthermore, this study will help understand the relationship of the surface of corrosion protective coatings and the interaction with its environment. Electrochemical impedance spectroscopy (EIS) is applied to evaluate the corrosion performance of a high performance, low VOC, two component polyurethane enamel and a high performance UV-cured coating system on carbon steel alloy A36 under immersion testing of sodium chloride solutions of surfactant admixtures. This electrochemical technique permits the evaluation of the properties of the coating system by monitoring its degradation (open full item for complete abstract)

Committee: Chelsea Monty Dr. (Advisor); Scott Lillard Dr. (Committee Member); Gang Cheng Dr. (Committee Member); Christopher Miller Dr. (Committee Member); John Senko Dr. (Committee Member) Subjects: Automotive Materials; Chemical Engineering; Engineering; Materials Science; Physical Chemistry