Standard quality control tests and electrochemical impedance spectroscopy (EIS) were used to examine changes in the properties of the barrier and porous layers in unsealed anodized aluminium specimens in three different thicknesses, that were exposed to 9 atmo-spheres with chloride concentrations from 3.9 to 684 mg m~(-2) d~(-1) in Spain, Portugal and various Latin American countries. The results confirm the conclusions drawn from visual inspections and gravimetric determinations in the first part of this series. Thus, a thick enough unsealed anodic film prevents local corrosion, even in highly aggressive environments. The results of both the EIS technique and standard quality control tests confirm that, in contrast to protective coatings of a different nature, the quality of unsealed anodic films improves with aging.
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