EFFECT OF DIFFERENT ACID ANIONS ON KINETICS OF THE FORMATION AND DISSOLUTION BEHAVIOR OF ANODIC ZIRCONIUM-OXIDE

Effects of sulfuric acid (H2SO4), phosphoric acid (H3PO4), nitric acid (HNO3), and hydrochloric acid (HCl) on kinetics of the formation and dissolution behavior of zirconium oxide (ZrO2) were studied using the impedance, potential, and galvanostatic techniques. The oxide film did not form galvanostatically in 1 M HCl because of dissolution simultan eously with formation while the rate of formation in other acids decre ased in the order: H2SO4 > H3PO4 > HNO3. Impedance and potential measu rements reflected the same dissolution process, with the rate of forma tion decreasing in the order: HCl > HNO3 > H2PO4 > H2SO4. The theory o f anodization was applied, and data were collected for reciprocal capa city, electrolytic parameters, and field strength. Activation energy d uring the oxide film formation was calculated as 4.99 kJ/mol. A genera l treatment was applied using three models under galvanostatic conditi ons.