Cobalt Electrodeposition in Nanoporous Anodic Aluminium Oxide Films with Different Oxidation Time

The anodic aluminum oxide films with different oxidation times were investigated using electrochemical techniques including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and open-circuit potential versus time. The stable open-circuit potential versus time indicates that the longer anodization time provides a larger block for cobalt electrodeposition. The EIS monitoring revealed the capacitance characteristics of the barrier layer. When the oxidation time is 4 h, the thickness and porosity of AAO film are 1517 nm and 16.4 % corespondingly, and the radius of the capacitive reactance arc is the smallest. The reduction peak current of CV is attributed to the change in diffusion coefficient of cobalt when oxidation time changes.