The influence of pre-anodization voltage on pore arrangement in anodic alumina produced by hard anodization

The influence of various pre-anodization voltage (Vs) on pore self-ordering process in anodic alumina (AAO) produced by hard anodization (HA) was investigated. It was demonstrated that the Vs has substantial effect on the pore arrangement in the AAO. Moreover, the results revealed that the pre-anodization under the mild condition is not necessary to form a long-range ordered AAO. When the HA process starts at relatively high Vs, only a small change of voltage and current during the second anodization stage is sufficient to rearrange the pores into the close-packed hexagonal structure. Excellent pore ordering was achieved when the samples were pre-anodized at 120 V.