Characteristics of the Porous Anodic Oxide Film Formed on Aerospace 7XXX Aluminum Alloy

7xxx series aluminum alloys are some of the most commonly used alloys for aerospace applications, they contain zinc, magnesium, and copper as the main alloying elements for the best specific mechanical properties, but also with the highest susceptibility to corrosion. Therefore, an effective corrosion protection system is required to fulfil structural integrity requirements for the product’s entire lifetime at least three decades typically. Anodizing, i.e. the formation of an anodic oxide film with good barrier properties and a porous surface, has been widely adopted as the critical scheme in a typical multi-layered aerospace corrosion protection system. In the present study, the properties of anodic oxide layers formed on 7055 T7951 plate at different gauges in chromic acid and tartaric-sulfuric acid were investigated, respectively; The effects of chemistry and crystallographic texture on optical appearance of the anodized 7055 plates were especially highlighted.