Real-time lmaging for Initiation of Localized Interfacial Reaction

点击翻译按钮获取中文摘要

Conventionally, mechanism and kinetics of localized interfacial reaction such as local corrosion have not been so cleared because of a lack of methods to investigate an initiation process of the reaction. A state-of-art micro-electrochemical method, which enables to investigate real-time changes in surface morphology as well as products due to localized electrochemical interfacial reaction, is developed and tentatively apPlied to analyze the initiation of local corrosion in this study. An ellipso- microscope, that is combination of null-type ellipsometer and CCD camera micro- imaging, is applied to titanium surface anodized in sulfulic acid and successfully revealed an anisotropic growth of oxide film depending on the substrate and localized degradation of the film in bromide ion-containing solution. Furthermore, a micro- capillary cell technique with 50 pm diameter sample combined with a long-distance optical microscope was developed and apPlied to potentio-dynamic and - static polarizations and electrochemical impedance spectroscopy of iron in sulfuric acid. It revealed that the passivation of the surface and stability of the passive film were strongly depended on crystallographic orientation of the substrate. Combinations of microelectrochemistry and optical microscopy might take a new turn of the research for the initiation of localized interfacial reaction caused by non-uniformity in the scale of surface microstructures.