Christopher A. Eardley

Electrodeposition of aluminium and aluminium/platinum alloys from AlCl3/benzyltrimethylammonium chloride room temperature ionic liquids

This paper shows that aluminium and aluminium/platinum alloys can be deposited from room temperature ionic liquids formed from an adduct of aluminium trichloride with benzyltrimethyl ammonium chloride. The advantages of this ionic liquid over the majority of those previously investigated is that it is less water sensitive, easier to purify and form and significantly more cost effective. Voltammetry and chronoamperometry were used to investigate the deposition and stripping of aluminium on Pt, Al and Fe electrodes. Hull cell tests were performed to obtain the optimum deposition conditions and bulk electrolysis showed that uniform, adherent, crack-free aluminium deposits could be obtained from such ionic liquids. Co-electrodeposition of Al with Pt was also studied and the nucleation mechanism was found to change significantly when Pt complexes were added to the ionic solution. The platinum ligands were found to change the solubility of the complex, but had little effect on the morphology of the deposited film.

Electrochemical investigations in liquid and supercritical 1,1,1,2-tetrafluoroethane (HFC 134a) and difluoromethane (HFC 32)

Abstract This communication outlines the use of HFC 134a and HFC 32 in both the liquid and supercritical states. The comparatively mild critical conditions are used to show that both of these solvents are important for studying electrochemical processes in the supercritical state. The higher polarity of these media in the supercritical state circumvent many of the problems associated with solubility, conductivity and ion adsorption on the electrode surface observed with other supercritical media also. The unprecedented wide potential window of HFC 134a is demonstrated and utilised for the oxidation of Xe and Cs + .

Novel Room Temperature Molten Salts for Aluminium Electrodeposition

SUMMARYThis work describes novel room temperature molten salts which can be used for aluminium electrodeposition. We have characterised the conductivity as a function of the bath composition and shown that the changes in conductivity occur because of an equilibrium between [Al2Cl7] and [AlCl2 The voltammetry of the optimum melt is analysed together with the mechanism of nucleation. Hull cell tests were performed and the morphology of the deposits was analysed using scanning electron microscopy. These room temperature molten salts have a number of advantages over those described in the literature including lower water sensitivity, greater ease of purification and greatly reduced cost. The electrodeposition of adherent, dull aluminium is demonstrated. It is also shown that soluble aluminium anodes can be used. These novel baths form a viable alternative to conventional methods of depositing aluminium.