Precursive Blistering in the Localized Corrosion of Aluminum

Observations have been made which indicate that blister formation is a general step in the pit initiation process in aluminum in aqueous chloride solutions. Evidence is presented which clearly shows that the oxide film is overtly broken by the mechanical stress resulting from the gas pressure in such blisters. The steps involved in the blistering process are outlined with a discussion of the evidence for each step.