In situ detection of differences in the electrochemical activity of Al2Cu IMPs and investigation of their effect on FFC by scanning Kelvin probe force microscopy

As we could recently show, scanning Kelvin probe force microscopy (SKPFM) is a very promising and powerful tool for the in situ investigation of filiform corrosion. Here we present how the underlying processes, namely the galvanic coupling of active head and intermetallic particles, can be visualised by performing SKPFM experiments under gas change conditions, i.e. by switching the atmosphere between nitrogen and air. It will be shown that, the different activity of the active particles can be detected by SKPFM at the buried coating/alloy interface and that these differences in activity play a role in determining the course of the FFC.

► In situ high resolution SKPFM for monitoring filiform corrosion.
► Not only the closest IMPs to active head but also more active ones are crucial.
► Different activity of the particles, based on gas change experiments, is determined.