Corrosion of Metal Films Observed Using In Situ and Ex Situ Electron Microscopy

Localized corrosion refers to the accelerated dissolution of metals and alloys due to the breakdown of their protective passive films at select sites [1]. Developing an understanding of localized corrosion phenomena has significant practical importance due to the deleterious effects of pit formation on the integrity of structural materials. However, localized corrosion is a challenging problem to study because of (1) the small dimensions of pit initiation sites; (2) the short timeframe between pit initiation and pit propagation; (3) the scarcity and stochastic nature of pitting events; (4) the difficulty of characterizing the thin passive film in aqueous environments; and (5) the dynamic evolution of the surface, potential and solution concentration gradients with time [2]. Here, we combine in situ liquid flow cell electron microscopy and ex situ electron microscopy to examine localized corrosion events in thin metal films.