Mechanism of Anodic Oxide Film Formation on Zircaloy-2, Zircaloy-4, Titanium and Niobium (Radio Tracer Technique)

V. Jeevana Jyothi¹, N. N. S. Aparna² And Ch. Anjaneyulu²

¹Depatrment of Chemsitry R.B.V.R.R. Women’s College, Nazrayanguda, Hyderabad (India). ²Department of Chemistry, Unviersity College for Women, Osmania University, Hyderabad - 500 007 (India).

The kinetics of anodic oxidation of zircaloy-2, zircaloy-4, titanium and niobium have been studied in 0.1M sodium methoxide without and with addition of a millimole of sodium phosphate at a constant current density of 8mA.cm-2 and at room temperature (300 K). the addition of phosphate ions found to improve the kinetics of film formation. This trend and mechanism of anodic oxide film growth is confirmed form radio – tracer technique using labeled phosphate ions. The conclusion of the results obtained is migration of anion impurity and accumulation of active phosphate in the layers of the oxide film formed.

Anodic oxide film; phosphate ions migration; mechanism; radio – tracer studies