Electrochemical impedance spectroscopic characterization of the oxide film formed over low modulus Ti–35.5Nb–7.3Zr–5.7Ta alloy in phosphate buffer saline at various potentials

摘要

Electrochemical impedance spectroscopic characterization of the low modulus Ti–35.5Nb–7.3Zr–5.7Ta alloy has been performed in phosphate buffer saline solution at 37 °C. Measurements were performed at various immersion intervals up to 720 h at OCP and also at various anodic potentials up to 2 V. The alloy exhibits a two time constant impedance response at the OCP and a one-time constant response at anodic potentials in the passive region. The thickness of the oxide film formed has been evaluated and the electrochemical interpretation of the results has been reported. Cyclic potentiodynamic profile of the alloy displays valve metal characteristics and the presence of a wide passive region that extends up to the maximum potential value of 2 V studied.