In the present study, the formation and growth of an oxide film on a titanium alloy
Ti6Al4V surface immersed in 3% NaCl solution using anodisation at various imposed
potentials was investigated by two electrochemical techniques, cyclic polarisation and
impedance measurements. In the cyclic polarisation studies at different scan rates, the
obtained curves show a large range of passivation, due to the formation of a protective
oxide film, generally TiO2. In addition, the negative hysteresis that appeared
during the cyclic polarisation with the shift of the corrosion potential in the more noble
direction (approximately +260 mV) may be explained by a reduction of the corrosion
products. It was found that the lower the scan rates the lower the passivation current,
and the scan rates did not have a significant effect on the potential or current of
corrosion. The impedance measurements (Nyquist and Bode plots) at various imposed
potentials show that Ti6Al4V has a capacitive behaviour in the passive field, due to the
formation and growth of the oxide film.