First-step anodization of commercial aluminium was carried out in 0.3 M oxalic acid at five temperatures –10, –5, 0, 5, and 10 ºC, keeping the anodization voltage (40 V) and time (15 min) constant. It is found that the current density, charge transferred, and thickness of porous alumina film increase exponentially with anodization temperature. The activation energy of the rate process of anodization determined from the Arrhenius plots of current density, charge transferred, and film thickness is found to be 0.357 eV with a standard deviation of 0.013 eV. Structural features of the porous alumina examined by SEM show that the pore diameter, interpore distance, and porosity increase whereas pore circularity and pore density decrease linearly with the increase in anodization temperature. Moreover, XRD studies of the anodized commercial aluminum substrate show that the intensity of diffraction peak pertaining to preferentially oriented crystallographic plane (311) is decreased whereas its full width at half maximum is increased at all anodization temperatures.

Syed Muhammad Junaid Zaidi and Muhammad. Zakria Butt