Optimization of anodizing process parameters for the volume expansion of anodic aluminum oxide film by taguchi method

The effect of anodizing voltage, electrolyte temperature and concentration of phosphoric and oxalic acids on the volume expansion of anodic aluminum oxide was investigated. The anodizing process parameters are chosen to their full extent of ranges that allow the anodization processes to be conducted without electric breakdown and to explore the highest possible volume expansion factor. The Taguchi L9 orthogonal array has been adopted to reduce the number of experiments, which data are analyzed using signal-to-noise (S/N) ratios and the analysis of variance (ANOVA). According to the results, anodizing voltage and electrolyte temperature play the significant roles on the volume expansion factor of AAO. Furthermore, the estimated optimum values of the process parameters are corresponding to anodizing voltage of 160 V, phosphoric acid of 1.1 M, oxalic acid of 0.14 M, and electrolyte temperature of 2 °C. The mean value of optimal volume expansion factor is predicted as 1.813. Confirmatory experimental value of volume expansion factor obtained for the optimum conditions is 1.894.