[Preparation and performance of through-hole AAO film]

Praseodymium nitrate was used as additives in preparing anodic aluminum oxide (AAO) films to improve its performance. AAO films were prepared by anodization method from a 15 vol. % H2SO4 solution with added praseodymium nitrate. The effects of Pr concentration and anodization voltage on the thickness and microhardness of AAO film were investigated, respectively. The oxide barrier layer of AAO film was removed with the method of combining etching of 5 vol. % H3PO4 solution with ultrasonic wave. treatment The effects of etching time and treating time with ultrasonic wave on the oxide barrier layer of AAO film were investigated respectively. The AAO films were characterized with EDAX and SEM techniques respectively. AAO film prepared in 15 vol. % H2SO4 solution with praseodymium nitrate added showed higher thickness and microhardness. The thickness of AAO films increased with the increase in anodization voltage, while the microhardness of AAO films decreased with the increase in anodization voltage in 19-23 V. When anodization voltage is 23 V, the thickness and microhardness of AAO film prepared in 15 vol. % H2SO4 + 0.4 Pr g x L(-1) mixture solution are as high as 162 microm and 275.1 HV respectively, which are 8.0% and 22.4% higher than that of film prepared in 15 vol. % H2SO4 solution (150 microm and 224.8 HV). The oxide barrier layer of AAO film was removed by combining etching in 5 vol. % H3PO4 solution for 13 min with ultrasonic wave treatment for 10 min, forming through-hole AAO film. The flocks of surface of the etched AAO film are Al2O3.