MACROSCOPIC STUDIES ON THE PROPERTIES OF THE ANODIC OXIDE-FILMS ON TITANIUM

The effect of fluoride ions on the formation and dissolution behaviour of anodic oxide films on Ti has been investigated in acidic fluoride media (pH=1) using impedance and galvanostatic techniques. As the fluo ride ion concentration and temperature increase the rate of oxide film formation decreases while the dissolution process increases. Oxide fi lm formed at high temperature and formation voltage was found to conta in more defect sites in the film than that formed at a lower one. Acti vation energies are calculated during the oxide film formation and dis solution and found to be 20.76 and 28.72 kJ/mol, respectively. Formati on rate and reciprocal capacitance data are reported as a function of polarizing current density. Values are recorded for the electrolytic p arameters A and B. Potentiostatic curves are derived from the galvanos tatic results.