Electrodeposition of Niobium and Aluminium from chloroaluminate melts onto Gold

Abstract

Niobium and aluminium have been electrodeposited onto gold substrate at 200 ºC under inert atmosphere from the melt of equimolar AlCl3+NaCl mixture with niobium added by anodic dissolution. Electrochemical deposition and dissolution of niobium and aluminium was investigated by cyclic, linear sweep voltammetry and potential step. Obtained samples were analysed by scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and X-ray diffraction. It was established that aluminium and niobium underpotential deposition on gold precedes overpotential deposition of niobium and subsequent aluminium deposition. Physical analytical methods indicated the formation of several niobium-aluminium, niobium-gold and aluminium-gold alloys in niobium and aluminium underpotential as well as in niobium and aluminium overpotential regions.