Recent Developments in Pitting Corrosion of Aluminium

Abstract

This paper draws attention to the practical importance of pitting. The environmental and metallurgical factors controlling pit initiation and propagation are reviewed in the light of recent researches. It is proposed that pits start because of the presence of flaws in the oxide film exposing anodic and cathodic areas and that these pits proceed because the conditions within the pit favour dissolution of the metal. The importance of copper and chloride ions in solution is stressed, as well as the lesser importance of sulphate.