Titled optimisation of anodising parameter with oxalic acid for the formation of anodic aluminium oxide

Abstract

This thesis discussed on the optimisation of anodizing parameter with oxalic acid for the formation of anodic aluminium oxide (AAO) by using Taguchi Methods. During one-step of anodization technique is performed, porous of AAO has been formed at the surface layer in the presence of oxalic acid. Since the pH value of oxalic acid is below than 5, it is suitable to produce nanoporous oxide layer. Regularity is defined as the structure with small or large size in pore formation, distance between each pore and the arrangement of AAO formed. The challenges in growing AAO are such as to get the specific size as we targeted to have and the regularity of the pores. Based on the literature review, four main anodizing parameters which are electrolyte temperature, electrolyte concentration, voltage and time should be well control so that the pore size and regularity can be control. In order to study the formation of AAO at the minimum size of pores and better regularity, anodizing parameter is optimized by L9 Taguchi Orthogonal Array. Scanning Electron Microscope (SEM) is used to observe the regularity of the pores and to measuring the pores size while X-Ray diffraction (XRD) is used to study the crystallinity structure of AAO. From the result, 20℃, 0.3M, 40V and 30 minutes are selected as the most optimum combination of anodizing parameter in order to study the pore size while 20℃, 0.4M, 25V and 30 minutes are selected as the most optimum parameter for regularity of AAO. The percentage influence of each main factor for pore size is also calculated to be 67% for electrolyte temperature and the rest which are electrolyte concentration, voltage and time give the same percentage (11%). Meanwhile, the percentage influence for regularity aspect are 39%, 37% 19% and 5% for voltage, electrolyte temperature, electrolyte concentration and time respectively. X-Ray Diffraction (XRD) analysis proved that aluminium oxide is presence after being anodized.