Droplet cell investigation of intergranular corrosion on AA2024

•A microcell is successfully used to monitor local current at a single grain boundary.•The measurements are linked to optical observation of the reverse of the foil.•The moment of full penetration is identified in a current transient.

An original method combining a droplet cell with direct optical interrogation of the reverse side of a 50 μm thick foil AA2024 has been tested to evaluate the possible analysis of the current during intergranular corrosion tests. The foil microstructure and the selected orientation were suitable for recording the current generated during the propagation in volume of a well-defined grain boundary trace. Even if it is impossible to reach a charge and mass balance from these preliminary attempts, it was demonstrated that it is possible, despite hydrogen evolution, to record a current transient resulting from the full penetration of an intergranular path.