Anodic polarization behavior of high purity aluminum in sodium chloride aqueous solution adjusted to various pH' s

Abstract

High purity aluminum was electrolyzed potentiostatically at various potentials in adjusted pH for 12 h. The relationship was investigated between the quantity of Al³⁺ in solution analyzed by oxine-chloroform extraction method and that of electricity determined by schematic integration from the time variation curve of current density. Taking an internal catholic reaction change in pH and formation of coating into account, the anodic current is caused by the reaction
Al-Al³⁺+3e^-
In alkaline solution, Al³⁺ migrates into solution by chemical dissolution of coating not directly through coating. In anodic and neutral solutions, Al³⁺ migrates into solution through coating.