On characteristics of pore size distribution in hybrid pulse anodized high-aspect-ratio aluminum oxide with Taguchi method

Many anodic aluminum oxide (AAO) templates were traditionally performed by potentiostatic anodization at 0---10 °C to inhibit the Joule's heat enhanced dissolution in aluminum oxide for ordered AAO configuration. In this article, the hybrid pulse anodization has been performed for offering the effective suppression of Joule's heat generation in high-aspect-ratio AAO formation at room temperature. The effect of pulse period, duty ratio, potential and electrolytic concentration on the evolution of pore characteristics was investigated using Taguchi method. The AAO morphology was captured by scanning electron microscope, and analyzed by gray-scale imaging in order to identify the pore size distribution and AAO thickness for Taguchi analysis. Short pulse-off period and low current density improved the uniformity of pore distribution. Moreover, high current density and intermediate pulse period/duty ratio can enhance the reaction rate and resulted in thick AAO. The evolution of AAO configuration and thickness were further correlated and discussed with pulse modulations and electrolytic concentrations.