A study on nanostructured of anodised aluminium template Synthesised by the mixture of phosphoric acid and acetic acid

Abstract

The formation of anodic aluminium oxide (AAO) film in anodising process has been studied. The anodising process was done in a mixture of phosphoric acid and acetic acid. The purpose of mixed acid solution as electrolyte is to increase the efficiency of AAO film formation. This study was performed to determine optimum parameter of anodising process in order to develop AAO film with diverse application in electronic field. The studies were focused on the influence of anodising parameters which are anodising temperature and anodising voltage on the growth of AAO film. The anodising temperature was controlled in the range of 5°C to 25°C and the anodising voltage was controlled from 70V to 130V respectively. The electrical properties of AAO film also studied via impedance measurement. The growth, morphology and composition analysis of AAO film were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. The results showed that the formation of AAO film was strictly influenced by the anodising parameter. The average pore diameter of AAO film was larger at temperature 15°C which is 87nm and the pores have more ordered arrangement. Meanwhile, the AAO film was shown have large pore diameter around 92nm at higher anodising voltage at 130V. The pore diameter of AAO film was gradually increased as the anodising voltage increase. The AAO film was shown to have highly ordered arrangement of pores at 130V of anodising voltage. The kinetic reaction of AAO film formation was expressed as percentage of mass change and AAO film thickness. At 15°C, the percentage of mass change showed a greater change which is 0.21% compared to the other anodising temperature. However, by increasing the anodising voltage, the percentage of mass change increased. Besides, the AAO film also showed greater thickness at 15°C which is 2.82μm. The thickness of AAO film decreased as the anodising temperature increased to 20°C and 25°C. At lower temperature, the thickness of AAO film is decreased. Meanwhile, the thickness of AAO film is strongly influenced by anodising voltage. Higher anodising voltage showed higher thickness of AAO film which is 2.8μm. The impedance measurement of AAO film revealed that the resistance of AAO film increased and the capacitance decreased as the thickness of AAO film increased. According to the results of this study, the optimum parameter of anodising should be in the range of 130V and the anodising temperature is about 15°C in order to obtain best characteristic of AAO film that can be related to the requirement of electronic applications.