Galvanostatic electrodeposition of aluminium onto aluminium from AlCl3+NaCl melt

Abstract

The processes of galvanostatic electrochemical deposition of aluminium onto aluminium from chloroaluminate melt made of equimolar AlCl3+NaCl mixture at 200°C have been investigated. The obtained deposits were characterized using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Galvanostatic Al deposition from the used melt onto aluminium substrate with smaller current densities (2-5 mA cm-2) gave relatively close-packed and well adhering deposits. Aluminium deposits obtained galvanostatically with current densities larger than 5 mA cm-2 are less compact, more crystalline and less adhering to the aluminium substrate. Al deposits obtained with 10 and 12.5 mA cm-2 were voluminous, very crystalline and poorly adhering to the working electrode substrate. These deposits were made of very small crystallites grouped randomly into more or less separate agglomerates.