Characterization of porous aluminum oxide films by metal electrodeposition

It is well known that porous (with underlying compact oxide) aluminum oxide films of varying pore size and diameter can be formed electrochemically on the surface of aluminum, depending on the oxidation conditions employed. In the present work, the properties of various porous Al oxide films were compared in terms of their electrochemical responses during silver electrodeposition. The cyclic voltammetric and current-time responses during silver deposition show an increased rate in the following sequence: sulfuric acid grown films (smallest pores), phosphoric acid grown (larger pores) and barrier oxide films (no pores), under identical applied voltages. Thicker porous oxide films formed after longer times of anodizing show lower deposition currents, while films formed at higher voltages (expected to yield larger diameter pores) result in higher silver deposition currents. Copyright (C) 1996 Elsevier Science Ltd