Corrosion properties of anodized aluminum: Effects of equal channel angular pressing prior to anodization

Many aluminum alloys are subjected to mechanical treatments before anodization. We have studied the effects of Equal Channel Angular Pressing (ECAP) on the properties of the passive film of aluminum 99.1%. Electrochemical measurements and micrography were used for characterisation. In 3% NaCl solution, anodization after ECAP leads to higher free potential values than that without deformation. Grain refinement and high dislocation density obtained by ECAP enhance the formation of a more continuous film after anodization. The destruction of inclusions increases pitting site density and leads to low-depth pits. The role of inclusions and pit sizes in the repassivation is illustrated.