Al-Zn Alloy Formation by Aluminium Underpotential Deposition from AlCl3+NaCl Melts on Zinc Substrate

Abstract

Aluminium was incorporated into polycrystalline zinc electrode surface by underpotential deposition from equimolar AlCl3+NaCl melt at 473, 523 and 573 K. The process was studied by linear sweep voltammetry and potentiostatic deposition/galvanostatic striping. The deposits were characterised by glancing incidence X-ray diffraction (GIXRD), Auger (AES) and electron probe micro-analyzer (EPMA). The electrochemical measurements showed evidence of Zn - Al alloys being formed. The constant-potential regions measured during the low-current striping correspond to the coexistence of two pairs of metastable intermetallic phases. However, the observed alloys could not be identified. The growth kinetics of the compounds is described.