Aluminium was incorporated into gold electrodes by underpotential deposition from an equimolar AlCl3+NaCl melt at 200 degrees C, 250 degrees C, and 300 degrees C. The process was studied by linear sweep voltammetry together with potentiostatic deposition/galvanostatic stripping. The deposits were characterised by electron microprobe analysis and glancing incidence X-ray diffraction. The electrochemical measurements showed clear evidence of intermetallic compound formation, and this was confirmed by the analysis, which showed several layers of successive bulk intermetallic compounds. The integral Gibbs energy of formation of the compounds is calculated and the kinetics of growth are described.