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Galvanic Corrosion

This application targets the evaluation of two dissimilar metals that are in-contact while in service.  When exposed to an electrolyte, one of the metals (the more ‘active’ one) will corrode and protect the more ‘noble’ one.  A Zero Resistance Ammeter (ZRA) controls two electrodes to be equal potential -- this simulates their state when in contact.  The direction of current flow determines which sample is active; and the magnitude of the current determines the level of activity.

Most often this mode is used to study dissimilar metals and is referred to as GALVANIC CORROSION.  As corrosion is a non-uniform process, the same principle can be applied to two sections of the same metal.  This ELECTROCHEMICAL NOISE experiment evaluates the impact of random, localized attacks that force these two identical materials to a dissimilar state.

Both actions are available within Princeton Applied Research’s VersaStudio-platform in the Corrosion section, as well as on the -300 series of VersaSTATs and the entire PARSTAT family.  Solartron Analytical's ModuLab XM uses its low-noise design and filter options to provide high-performance in a ZRA configuration.

The scanning techniques available with the VersaSCAN platform provide local information about the electrochemical events at the sample’s surface.  The SVET technique is uniquely suited to study the impact of Galvanic Couples or Welds by imaging voltage-fields in solution that are directly correlated to local anodes/cathodes.

Two K0235 Flat Cells can be assembled together as a convenient test cell for either GALVANIC CORROSION or ELECTROCHEMICAL NOISE experiments.