Impacts of Processing Parameters on Morphology of Pores for Anodic Oxide Film Prepared on Aluminum Foil by Twice Anodization

Abstract

Aluminum foil was anodic oxidized by a two-step anodization process in oxalic acid solutions. While the influence of processing parameters, such as voltage, time and solution concentration, for the 1st and 2nd steps of anodization process on the characteristics of pores of the anodic aluminum oxides(AAO) films was investigated. Results show that for the 1st anodization, the pores spacing increases with the rising voltage, yet the anodization time and the concentration of oxalic acid solution have almost no influence; for the 2nd anodization process, the pores spacing doesn't change when varying the voltage, the anodization time and the concentration of solution, but the pore diameter rises greatly with the rise of the voltage. The pores of the AAOs films are well arranged in a form of hexagonal array. Furthermore, the shape of the pores changes slightly when increasing the voltage for the 2nd anodization. High concentration(up to 0.4 mol/L) oxalic acid solution for the 2nd anodization resulted in an oriented piercing of the pore's wall, even a dissolving of the AAO layer, but the pores arrangement was not affected.