In-situ analytical and electrochemical evaluation of interfacial bonding and performance of corrosion protective coatings

摘要

The initial adhesion and resistance against delamination of organic coatings on metal surfaces highly depend on the polymer/oxide/metal interfacial chemistry. Therefore, it is crucial to control and understand the bonding mechanism originating at these interfaces in order to achieve long-term stability. While the type of bonding contributes to the strength of adhesion, the nature of the interface depends on both functionality present in the organic molecules of the coating and the nature of the oxide film e.g. hydration, hydroxyl content, oxide thickness, surface morphology and chemical composition. Studying the bonding properties of the polymeric coating to the metal (oxide) surface is experimentally difficult, because the interface is hard to be reached by analytical techniques due to the relatively high thickness of the polymer coatings. Consequently, the interfacial bonding can be modeled through adsorption of functional group, i.e. representative interfacial adhesive molecules, on differently pretreated surfaces by means of bonding mechanism (FTIR) and affinity (XPS) studies. Furthermore, the buried interface and delamination mechanisms at this location can be studied in-situ by Scanning Kelvin Probe (SKP) measurements and a novel integrated ATR-FTIR and electrochemical impedance spectroscopy (EIS) system in a Kretschmann geometry.