Room temperature anodization of aluminum and the effect of the electrochemical cell in the formation of porous alumina films from acid and alkaline electrolytes

Abstract

Nanoporous alumina was produced by anodic oxidation of aluminum in both acidic and alkaline electrolytes. Previous reports indicate that nanoporous aluminais mainly produced from strongly acidic electrolytes, and with the use of a low freezing temperature controlled bath to control the propagation and growth of the pores. We design an in-house electrochemical cell with an electronic circuit box attached, to control the anodization of aluminum at room temperature. The electrolytes used were phosphoric acid solution and sodium hydroxide solution. The pH of the acidic electrolyte was adjusted to 1, 3 and 5 with an applied potential of 50V and anodization time of 1 and 3 hrs, respectively, while the alkaline electrolyte pH was adjusted to 9, 11 and 13 with an applied potential of 40V and the templates anodized for 5 hrs. The micrographs of the nanoporous alumina formed from these electrolytes confirm that the nucleation and growth of nanoporous alumina films is achievable with the aid of the electronic circuit box connected to the electrochemical cell.