Behavior of Al-Ga Alloy on the Negative Side of the Open - circuit Potential in Sodium Chloride Solution

Abstract

The influence of the addition of small quantities gallium to high-purity aluminium on its electrochemical behaviour at high cathodic potentials (up to -2.0 V vs. SCE) was investigated using the potentiostatic pulse method. After cathodic polarization, anodic current was traced vs. time in order to determine the quantity of charge necessary for oxidation of substances formed. Anodic current responses to the return to the EOCP were also recorded in the period of 1 s. Time responses of the cathodic and anodic current were analyzed. The range of low and high cathodic potentials (LCP, HCP) was defined for all the samples. It has been established that the oxide film retains its properties in the LCP range, while in the HCP range cathodic breakdown and hydration of the oxide take place. Electrochemical methods complemented by SEM and EDAX analysis before and after the cathode pulse of -1.9 V vs. SCE.