Change of the antimony anodizing kinetics by coating the electrode with a thin film

Abstract

The present research work is dedicated on the processes kinetics description of the antimony anodization in potassium phosphate (K 3 PO 4 ) aqueous solutions. The data have shown that the slope of the kinetic curves is dependent on the phosphate solution concentration. Besides, their mathematic approximation has revealed occurrence of a critical phosphate solution concentration of 0.11 mol dm -3 . At this concentration, the slope of the kinetic curve tends to zero. Above this critical concentration, induction periods occur during the anodization. Additional experiments were performed with thin Sb 2 O 3 layers preliminary deposited in vacuum. This approach has enabled to define the impact of such layers on the kinetic behavior during the anodization process. The results have shown that various stages of the process could be skipped. The final data analysis has confirmed the suggestion that the induction periods and voltage variations during the anodization process are caused by the formation of a thin Sb 2 O 3 film, whose dielectric properties change with the film thickness increment.