Electrodeposition of Aluminum from 1,3-Dimethyl-2-Imidazolidinone/AlCl₃ baths

Abstract

This study investigated the use of novel organic solvent baths for the electrodeposition of aluminum at near-ambient temperatures. It was found that Al metal can be electrodeposited from baths that were composed of 1, 3-dimethyl-2-imidazolidinone (DMI) and AlCl₃, with an AlCl₃ concentration greater than 50 mol%. IR spectroscopy indicated that Al₂Cl₇⁻ions were present in the baths that contained >50 mol% AlCl₃, where the electrodeposition of Al occurs from Al₂Cl₇⁻ion. The DMI/AlCl₃ baths with AlCl₃ concentrations between 59 and 64 mol% retained a single liquid phase without precipitation at 25 ℃, and therefore, they can be used for Al electrodeposition near room temperature. Smooth Al films could be obtained by galvanostatic electrodeposition at 40 ℃ using a DMI/AlCl₃ bath with the addition of a trace amount of 1, 10-phenanthroline.