In the present work, we demonstrate that anodization in a nitrate containing organic electrolyte, under specific conditions, can be used to achieve highly aligned nanoporous oxide layers on Ti and Ta substrates. These layers after formation consist of amorphous TiO2 and Ta2O5, respectively, with regular pore sizes in the range of 20 to 30 nm. The amorphous layers can easily be crystallized by annealing. A main geometric feature of the layers is that they show a through-hole morphology which is considered to be of high interest for various types of membrane applications.
(© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)