Effect of Etching on Nanoporous Anodic Alumina

Abstract

Nanoporous anodic alumina were fabricated by using aqueous oxalic acid electrolyte via the simple and convenient electrochemical anodization method. The pore formation resulted from the interaction of surface aluminum with the prepared electrolyte of 0.3M oxalic acid having pH value less than 5. The phase purity and the morphology of the prepared porous alumina were studied by using X-ray diffraction and scanning electron microscopy respectively. Before pore widening, aluminum oxide nanopores of average pore size ~ 40 nm were obtained. However, after pore widening, nanopores of average pore size ~ 64 nm were obtained. For proper understanding of the formation of porous alumina nanopores, formation mechanism was discussed in detail by using current density–time spectra.