Efficiency of anodising of Al–Cu alloy in sulphuric acid at low potentials

Abstract The effect of copper on anodising of aluminium in sulphuric acid at low potentials has been examined for a sputtering-deposited Al–0·75 at.-%Cu alloy, using ion beam analysis and transmission electron microscopy. The aim was to determine the relationship between the potential and oxygen generation, with copper in the anodic film in either a metallic or oxidised form. The findings revealed that ∼30 to 40% of the cell charge is used in oxygen generation at potentials between 2 and 8 V(SCE). The charge of Al3+ ions in the film indicated overall efficiencies of film growth that increased from 23 to 41% over the potential range.

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