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Advances in Materials Science and Engineering
Volume 2016, Article ID 1374897, 12 pages
http://dx.doi.org/10.1155/2016/1374897
Research Article

Anodisation of Aluminium Alloys by Micro-Capillary Technique as a Tool for Reliable, Cost-Efficient, and Quick Process Parameter Determination

1Materials and Surface Engineering Group, Technische Universität Chemnitz, 09107 Chemnitz, Germany
2Center of Engineering Materials, State Materials Testing Institute Darmstadt (MPA), Chair and Institute for Materials Science (IfW), Technische Universität Darmstadt, 64283 Darmstadt, Germany
3Composite Materials Group, Technische Universität Chemnitz, 09107 Chemnitz, Germany

Received 20 September 2015; Revised 25 January 2016; Accepted 7 February 2016

Academic Editor: Gianluca Percoco

Copyright © 2016 Daniela Nickel et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Anodisation is essential for improving surface properties of aluminium alloys and composites regarding wear and corrosion behaviour. Optimisation of the anodising process depends on microstructural constituents contained in aluminium alloys and represents a key task, consisting of the control of process parameters and electrolyte formulation. We applied the micro-capillary technique known from corrosion studies and modified it to form anodic aluminium oxide films on high-strength aluminium alloys in comparison to pure aluminium in sulphuric acid. A glass capillary with an opening of 800 μm in diameter was utilized. Corresponding electrochemical measurements during potentiodynamic and potentiostatic anodisation revealed anodic current responses similar to conventional anodisation. The measurement of film thickness was adapted to the thin anodised spots using ellipsometry and energy dispersive X-ray analysis. Cross sections prepared by focused ion beam milling confirm the thickness results and show the behaviour of intermetallic phases depending on the anodising potential. Consequently, micro-capillary anodising proved to be an effective tool for developing appropriate anodisation conditions for aluminium alloys and composites because it allows quick variation of electrolyte composition by applying low electrolyte volumes and rapid film formation due to short process durations at small areas and more flexible variation of process parameters due to the used set-up.