THE INFLUENCE OF IONIC LIQUID ELECTROLYTE STABILITY ON THE PROPERTIES OF ELECTROPLATED ALUMINIUM LAYERS
Patrick Kosmus (a,b), Luciana Vieira (a,b), Bernhard Gollas(a,b) and Oliver Steiner (c)
aCEST, Viktor-Kaplan-Straße 2, 2700 Wiener Neustadt, Austria bICTM, Graz University of Technology, Graz, Austria cInstitute of Chemistry, Analytical Chemistry,
15:20 - 17:30 Thursday 24 October 2013 Foyer Alte Technik Ionic liquids (ILs) are a novel class of solvents with ionic character. The term ionic liquid is used for organic salts with melting points below 100°C. Up to now their use has been studied primarily in inorganic and organic synthetic chemistry with respect to sustainable and green chemistry [1]. Due to their ionic character they might be used as electrolytes for electroplating of materials that are not accessible from aqueous solutions [2]. Recently, it has been demonstrated that the electrodeposition of dense, matt to bright Al-layers from electrolytes based on a Lewis acidic mixture of AlCl3 and 1-ethyl-3-methylimidazolium chloride (EMIMCl) with some additives is feasible on lab scale [3]. However, decomposition products of the electrolyte may affect the quality of the coatings.
We have investigated the ageing of the IL EMIMCl/AlCl3 with different additives in order to determine the chemical and electrochemical stability of the electrolyte for aluminium plating. We thus present a concept for long-term electrodeposition and storage experiments. The electrolytes were characterized by Hull cell experiments and cyclic voltammetry. NMR and HPLC/UV-VIS/MS techniques were used to identify impurities or decomposition products in the ILs. Furthermore, we studied the influence of ageing of the electrolytes on the morphology of aluminium coatings on mild steel substrates. The aluminium layers were characterised by optical microscopy, SEM, FIB and XRD. It was observed that aging of the electrolyte and the presence of decomposition products affects the quality of the aluminium coatings.
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[1] M. Maase (Ed.), Ionic Liquids in Synthesis, Wiley, 2008.
[2] F. Endres, A.P. Abbott, D.R. MacFarlane (Eds.), Electrodeposition from Ionic Liquids, Wiley 2008.
[3] A. Alemany, I. Malkowsky, U. Vagt, M. Maase, M. O'Meara, Plat. Surf. Finish. 2010, 97, 34-37.
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