Fabrication and characterization of porous anodic alumina films from impure aluminum foils

We report here on the fabrication of porous anodic alumina (PAA) films from commercially available impure aluminum foil. While the expensive ultrapure PAA films are restricted to potential applications in nanoelectrophotonics, the impure PAA films are more suitable for large-scale applications, such as in catalysis and filtration. The anodization current behavior and chemical composition of the resulting PAA films from impure and ultrapure foils were found to be similar for the same set of anodizing conditions. However, the PAA films from impure aluminum foil contained pore arrays of much smaller size and less consistently sized pores than those of PAA from ultrapure foils. We find that these qualities are improved by either annealing or electropolishing the aluminum foil prior to anodization, although not to the degree of PAA produced from ultrapure foils. Greater improvement is found for annealed foils compared to electropolished foils. (c) 2006 The Electrochemical Society.