Scanning electrochemical microscopy is a method that incorporates an ultramicroelectrode capable of facilitating electrochemical reactions paired with an XYZ positioning system capable of micron-level movements. This study investigates the corrosion behavior of structural transition joint clad material that contains steel, pure aluminum, and an aluminum alloy blast welded into a single joint. This study will characterize the corrosion response of the structural transition joint and identify the galvanic activity measured between its layers. High-temperature coatings in this study are designed to be used effectively up to 1400?F. In this study, we characterized several commercial high-temperature coatings exposed to different levels of heat. General trends of decreasing barrier performance were observed with the exception when these coatings are exposed to their rated temperature limit of 1400?F, at which the barrier increased slightly, indicated by their low-frequency impedance modulus. The cause is a combination of sintering and oxide formation.

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This project involved the improvement of several properties of the current “universal” primer coating sold by Kelly-Moore Paint Company. This formulation is an all purpose primer used both for interior and exterior applications. However, its corrosion resistance has room for improvement. The addition of sodium nitrite, an aminocarboxylate salt, and a zinc phosphate-based additive were all tested as corrosion inhibitors. In addition, during the project the coating binder was changed to improve adhesion. After a systematic experimental program, a new “universal” primer with increased corrosion resistance and adhesion was formulated. A direct to metal top coat formulation sold by Kelly-Moore Paint Company was reformulated in order to produce a coating with better corrosion resistance and gloss retention. Five new latexes were investigated. Each formulation was tested for several properties including adhesion to metal substrates, water immersion resistance, accelerated UV exposure resistance, and outdoor exposure resistance. This effort resulted in a formulation that showed promise as a replacement for the current product; however, its adhesion was inadequate. Further work is needed to improve this coating.

Cross-linked polymers are of great importance to industrial practice and theoretical studies. The unique network structures of these materials have endowed them with many superior properties. In this thesis, we study cross-linked polymers from both of experimental and theoretical sides, with an emphasis on the formation process and properties of the prepared networks. Two specific problems are investigated: development of polymer coatings over solid particles with in situ curing, and molecular dynamics (MD) study of network formation kinetics and structure-property relationship. In the study of polymer coating, a hot-melt coating process for solid particles is developed. Phenolic resin is used to coat the substrates and subsequently cured in situ. Among various processing parameters, temperature is found to play an especially important role in the coating performance. Higher temperature leads to stronger coating layers with better barrier properties, whereas lower temperature is preferable for better surface morphology. These two trends can be partially reconciled with ramping temperature profiles; however, the improvement is eventually limited by the rate of heat transfer. In MD study, the effects of precursor topology on the formation, structure and mechanical properties of polymer networks are studied. Cross-linked polymer networks are synthesized from three sets of precursors with varying chain length. Little difference is observed between these networks in typical properties including radial distribution function, overall statistics of network connectivity, and glass transition behaviors. The elastic modulus of the network is found to correlate strongly with the number of elastic strands in the network, except at the highly-cross-linked limit where substantial discrepancy is observed between networks from different precursors. Although these final networks contain a similar level of structural defects, the choice of precursor has a significant effect on the spatial distribution of the defects, which explains the precursor dependence of their mechanical property observed in the tensile test. / Thesis / Master of Applied Science (MASc)

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