The Influence of Input Factors of Aluminium Anodizing Process on Resulting Thickness and Quality of Aluminium Oxide Layer

In order to optimize the technological process of aluminium anodic oxidation, the possibilities of usage of sodium chloride in the electrolyte has been studied, since very small concentration of sodium chloride allows us to reduce concentration of other components of the electrolyte. Also the influence of sodium chloride concentration in the electrolyte on the final thickness and quality of the formed anodic aluminium oxide (AAO) layer has been investigated in this paper. In contrast to common anodizing experiments, in which the influence of only one separate factor at a time is considered, in our research all relevant factors (four chemical factors) were varied simultaneously according to the methodology of statistical experimental design, i.e. design of experiments (DOE). Based on the evaluation of experimentally obtained data by application of mathematical-statistical methods and theory of neural networks, the relationship between the concentration of sodium chloride in the electrolyte and final thickness of the AAO layer was experimentally determined. Thanks to that it was possible to obtain the predictive model which can determine the final thickness of AAO layer. Moreover, the results of this research allows us to reduce the concentration of other components of the electrolyte up to the level of 25% of commonly used concentration of these electrolyte components designed for the process of aluminium anodic oxidation.