ELECTROCHEMICAL STUDIES WITH COPPER-BASED ALLOYS - OPEN-CIRCUIT POTENTIAL OSCILLATIONS IN ALKALINE MEDIA

In open-circuit potential measurements of certain Cu-based alloys in N aOH solutions oscillations were observed in Cu-Al and Cu-Ag-Al. Studie s with various electrolyte concentrations and rotation speeds of the e lectrode led to a possible explanation of the phenomenon in terms of A l dissolution altering the main Cu dissolution/passivation process. Th e accumulation of aluminate ions on the interphase and its transportat ion to the bulk solution are the main causes of the oscillations.