Influence of Fe-bearing particles and nature of electrolyte on the hard anodizing behaviour of AA 7075 extrusion products

Porous anodic alumina formed by anodization of aluminum alloy (AA1050) and high purity aluminum

“…Moreover, the literature reports showed that the presence of Si and Fe impurities at the metal/oxide interface, where the growth of oxide mainly occurs, block significantly the growth of oxide [33][34][35][36]. The local accumulation of alloying elements in a given region of the metal/oxide interface influences local rates of oxidation and consequently modifies the oxide morphology.…”

Microstructure and properties of high strength aluminium alloys for structural applications

“…Si and Mn impurities, when present above certain critical limits, stabilize the Al 12 (FeMn) 3 Si based phase, and it is these particles that survive the hard anodizing treatment, inhibit the local growth of the anodic oxide film in Al-Zn-MgCu alloys [see Figure 10(a)] [35] and causes heating ("burning") at the edges of the components due to a steep rise in voltage with hard anodizing time. This interrupts the hard anodizing process and the required coating thickness is obtained following several steps.…”

Fabrication and Structural Studies of Porous Anodic Oxide Film on Pure Aluminium and Aluminium Alloy (AA 1100)

“…The slight retardation in growth process is due to presence of alloying elements in Al 1100. When Fe and Mn are the alloying element they affect the film formation characteristics like field assisted film dissolution and conductivity during the formation of oxide film [17][18] . Figure 1.…”