Abstract

We have carried out a systematic investigation of the anodization procedure in order to determine the exact chemical mechanism of the dissolution process responsible for pore formation in nanoporous alumina templates. We measured the anodization current as a function of time and compared it with the thickness of porous aluminum oxide layer obtained from cross-section scanning electron microscopy images. From this, we calculated the number of moles of electrons generated per mole of porous alumina grown. This analysis is consistent with a reaction mechanism in which aluminum is converted to aluminum oxide in addition with the direct transfer of aluminum ions across the thin barrier aluminum oxide into the electrolyte. Hence, experimental evidence is reported that indicate that the dissolution process observed is that ofAl³⁺ ions migrating across the barrier layer and dissolving into the solution. Contrary to the suggestion of some authors, these experiments indicate that at most a negligible amount of oxide dissolves during the anodization of aluminum.

Notes

Originally published in Journal of the Electrochemical Society v.154 no.1 (2007), E8-E12. doi: 10.1149/1.2382671

Keywords

anodization, nanoporous materials, alumina, porosity, scanning electron microscopy, dissolving

Disciplines

Nanoscience and Nanotechnology

Publisher

The Electrochemical Society

Publication Date

11-8-2006

Rights Information

© 2006 ECS - The Electrochemical Society

Rights Holder

The Electrochemical Society


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