Application of pulse voltage for enhancing uniform nano-structured anodic aluminum oxide

Conventional anodic aluminum oxide (AAO) process was performed in low electrolytic temperature and high purity aluminum (Al) foil. In this article, pulse reverse voltage was applied to commercial purity (99%) and high purity (99.997%) Al foils at room temperature to form AAO. DC method was also used as a reference. The pulse AAO method provides advantages not only the reduced process complexity and at low cost but also better uniformity than that performed by DC one. The results show that pore uniformity can be improved by pulse reverse voltage in the 3h duration anodization compared to DC method. The pulse reverse voltage presents the high uniformity (77~78%) in both low and high purity Al. The effects on different Al purity and process durations will further discussed in this study.