Study of corrosion resistance of colored anodized aluminum with Quinizarin using cyclic voltammetry and impedance measurement methods

The effect of coloring condition of aluminum with Quinizarin (1,4-dihydroxy anthraquinone) on the corrosion of Al in sulfuric acid solution was studied using cyclic and AC voltammetry and impedance measurement methods. The changes in the corrosion resistance of colored aluminum plates were evaluated by measuring the magnitude of impedance and cyclic voltammetric responses of anodized and colored plates.The current and threshold potential of corrosion responses strongly depend on the applied conditions during anodizing, coloring and sealing stages. In addition, significant changes in impedance at AC voltammogram were observed, when the plates were colored under various conditions. In this study, the surfaces of the aluminum plates were also studied by scanning electron microscopy (SEM). Comparison of SEM images of the colored and uncolored aluminum specimens showed that the uncolored surface contained a significant number of pits. The results indicated that coloring aluminum with Quinizarin and sealing it with boiled water could reduce corrosion of this metal.