A comparative study of electrochemical barrier layer thinning for anodic aluminum oxide grown on technical purity aluminum

• Nanoporous anodic aluminum oxide was formed.
• Electrochemical barrier layer thinning was performed.
• Efficiency of thinning was investigated by electrochemical impedance spectroscopy.
• Electrodeposition of nickel was done for the most efficient thinning.

Anodization of AA1050 foil in 0.3 M oxalic acid at 50 V was performed and nanoporous alumina was formed. Four various approaches of electrochemical barrier layer thinning with varied voltage steps were applied to optimize the experimental conditions. Scanning electron microscopy was employed to investigate the bottoms of the anodic alumina after electrochemical barrier layer thinning. Values of the barrier layer thickness derived from Bode plots extrapolations confirmed the FE-SEM observations. For the most suitable barrier layer the thinning procedure was applied to successfully form nickel nanowires via pulse electrodeposition.