Formation of Through-Hole Porous Anodic Aluminum Oxide Layer Locally with 3D Printed Solution Flow Type Microdroplet Cell

In this study, a 3D-prinited solution-flow type microdroplet cell (SF-MDC) is employed as a new technique for the fabrication of porous anodic aluminum oxide (AAO) layer using oxalic acid electrolyte on aluminum. The surface morphology of the porous AAO film was characterized by a scanning electron microscope. The aim of this study was to fabricate a through-hole porous alumina layer in a single step anodizing process and to investigate the influence of anodized voltages and scanning speeds on the thickness and pore structure of alumina layer. The results showed that the pore diameter and interpore distance were directly proportional to the anodizing voltage. The thicknesses of formed AAO films were found to be 35.5, 50.7, and 81.6 μm at scanning speeds of 10, 5, and 2.5 μms⁻¹, respectively. Through-hole porous AAO was successfully fabricated at room temperature without chemical etching. The SF-MDC fabrication technique is proposed as an environmentally attractive and suitable process for the fabrication of porous AAO layers.