In this paper, the electrochemical properties of high - purity aluminium with the addition of small amounts of gallium at high cathodic potentials have been investigated. The anodic current was followed through time in order to determine the quantity of charge needed for the formed substances oxidation. Anodic current responses for the period of 1 s were recorded. Time responses for the cathodic and anodic currents were recorded and showed in characteristic diagrams. The range of low and high cathodic potentials (LCP, HCP) was defined for all samples. For the experimental work, standard electrochemical cell with saturated calomel electrode (SCE) and platinum counter electrode were used. The solution 2 M NaF was used for this work.

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.