A Voltammetric Investigation of AC Corrosion Phenomena at an Aluminum Electrode in Hydrochloric Acid

Abstract

Abstract The electrochemical behavior of Al in HCl has been studied by cyclic voltammetry, square-wave chronoamperometry, and square-wave chronopotentiometry. High speed cyclic voltammetry was studied thoroughly, and the effects of temperature, HCl concentration, potential sweep rate, and cathodic potential limit were examined. Relevant parameters that can be determined from the cyclic voltammetric i-V curve include the breakdown and protection potentials for Al, the onset potential for hydrogen evolution, and the magnitude of the anodic and cathodic currents. The degree of passivity, which is reflected in the anodic breakdown potential and the magnitude of the anodic current, decreased with increasing solution temperature and HCl concentration, and increased with higher sweep rates. The nature of the Al passivation that occurs during the cathodic half-cycle depends on the cathodic potential limit. These processes and their relationship to the voltammetric curves are discussed in detail.