Polarisation behaviour of Al–Zn–Ga alloy in chloride medium

Abstract

The electrochemical response of Al-Zn-Ga alloy in chloride medium was studied. For this purpose, linear sweep voltammetry and open circuit potential (OCP) measurements were employed and surface characterisation was performed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The presence of Ga whether as alloyed element in the ternary alloy or deposited from the electrolyte solution onto pure Al or onto Al-Zn alloy causes a displacement of the onset of the process of dissolution towards more negative potential in a chloride solution. The anodic behaviour of the Al-Zn-Ga alloy can be interpreted in terms of an amalgam mechanism, where the homogeneously distribution of Ga in the alloy assures the formation of a superficial Ga-Al amalgam.