nano-templates

D. Regonini, C.R. Bowen, D.Allsopp and R. Stevens
Materials Research Centre, Department of Mechanical Engineering, University of Bath, BA2 7AY, UK

Abstract

The anodising of aluminium has been investigated with the aim to realise nano-porous structures and nano-porous oxides for use as nano-templates, as gas-sensor systems and as catalysis. Before undergoing electrochemical oxidation, aluminium samples were cleaned in acetone, annealed at 500oC under nitrogen flow and electropolished using a mixture of perchloric acid, ethanol, 2-butoxyethanol and water. The pre-treated metal surface was analysed with a non-contact surface profilometer. The best pre-treatment results were achieved applying an electropolishing voltage between 50 and 60 V for a time of 20-30 sec. Anodising was carried out under potentiostatic conditions, using oxalic acid as electrolyte. Different combinations of processing parameters (anodisation time, cell temperature, number of anodisation steps) were used in order to optimise the process. Anodised alumina samples were characterised with scanning electron and atomic force microscopy. Partially ordered nano-porous alumina was obtained, however further investigations are required to optimise the production of highly self-ordered porous structures.