ELECTROCHEMICAL BEHAVIOUR OF ALUMINUM IN 1M NaCl - EFFECTS OF ADDED AlCl//3.

The open circuit potential (OCP) of an aluminum electrode is shifted rapidly from minus 0. 8 V (vs SCE) to minus 1. 2 V (vs SCE) in the presence of 0. 1M AlCl//3 and stays at minus 1. 2 V for about 16 days. The addition of AlCl//3 also results in a large limiting current in the cathodic polarization studies and affects the reduction of H//2O at the electrode. An amorphous white product is formed on the surface of the electrode in the limiting current region. These effects are found to be a function of surface pretreatment, time of immersion prior to polarization and concentration of aluminum chloride. The observations are analyzed by current-time curves, cyclic voltammetry, impedance and scanning electron microscopic studies.