Pore Distributions in Porous Anodic Aluminum Oxide (PAAO) Surfaces of Pure and Commercial Aluminum Substrates

Abstract

Porous anodic aluminum oxide (PAAO) surfaces were developed on pure aluminum (PA) and commercial aluminum (CA) substrates by anodization as a function of voltage in phosphoric acid bath at 278 K and were analyzed by scanning electron microscopy. The interpore distances were plotted in the form of frequency histograms to examine pore-ordering characteristics. Self-ordered porous structures have been obtained at 200 and 160 V for PA and CA substrates respectively as can be evident from histogram and FFT analysis. However, the overall ordering improves with the increase in voltage for both types of substrates. Pore ordering, though relatively better for PA is not very different from that for CA, indicating that CA can be used as a potential substitute of PA for bulk application.

Keywords: Porous anodic aluminum oxide (PAAO), two-step anodization, self-ordering, pore formation voltage