Growth of Anodic Aluminum Oxide Films Without pH-Buffer

Abstract

The anodic behavior of abraded pure Al in un-buffered solutions was previously addressed using the cyclic voltammetry and the numerical modeling. In buffer solutions such as borate and phosphate, the Al oxidation current increased rapidly at first and then reached a plateau region, and was analyzed in terms of the high field conduction model and oxide dissolution. However, the anodic current in un-buffered solutions such as sulfate continued to increase with potential. Introducing additional contributions to the earlier model by assuming that the oxide formation efficiency is diminishing with the degree of surface acidity, the features of the anodic behavior in un-buffered solutions, absent in buffered solutions, were simulated.