Passive and Semiconducting Properties Assessment of Commercially Pure Tantalum in Hank’s Physiological Solution

In this study, various electrochemical measurements were used to evaluate the passive and semiconducting properties of commercially pure tantalum (Ta) in Hank’s physiological solution at 310 K (37 °C). Potentiodynamic polarization and electrochemical impedance spectroscopy results show that the passivation of pure Ta immersed in Hank’s physiological solution improves over time. Mott–Schottky (M–S) tests indicate that the passive layers of pure Ta in Hank’s physiological solution behave as n-type semiconductors and longer immersion times do not lead to any inversion of semiconducting behavior. Additionally, M–S tests show that as the immersion time increases, the donor density of the passive layer decreases. Finally, scanning electron microscope micrographs and energy-dispersive spectroscopy results reveal that Ta is less likely to experience significant pitting or buildup of undesirable corrosion products after longer immersion times in this physiological solution.