ON THE ELECTROCHEMICAL-BEHAVIOR OF ALUMINUM IN ACIDIC CHLORIDE SOLUTION

The electrochemical behaviour of aluminium in 0.1 M hydrochloric acid solution positive of the open circuit potential (OCP) has been studied using open circuit potential measurements, linear sweep voltammetry and electrochemical impedance spectroscopy at stationary and rotating high purity aluminium disc electrodes. Freshly polished electrodes show an induction time before the OCP changes negatively towards its steady-state value. Steady-state current-voltage profiles show two distinct almost linear, non-Tafelian regions positive of the OCP. Evidence for pitting corrosion through a salt film and dissolution via ionic migration through the thin oxide film as parallel corrosion paths is discussed.