In order to evaluate the electrochemical properties of the passive film on pure Tantalum, various electrochemical methods including polarization, impedance spectroscopy and Mott–Schottky were applied in Ringer solution at 37 °C. Obtained results arisen from polarization and impedance spectroscopy measurements revealed that as the anodic passive potential increases, pure Tantalum samples passive response in Ringer solution was improved. Mott–Schottky measurements showed that the passive oxide films behaved as ntype semiconductors and passive potential cannot change the conductivity type of the passive oxide films. Moreover, Mott–Schottky measurements depicted that less donor densities in the passive film increased corrosion resistance of pure Tantalum in the test solution owing to higher anodic passive potential.
