Insight into physical interpretation of high frequency time constant in electrochemical impedance spectra of Mg

• DOI: 10.1016/j.corsci.2021.109501
• Publication Date: 2021-04-27T17:40:39Z
• Authors: Linqian Wang; Darya Snihirova; Min Deng; Cheng Wang; Bahram Vaghefinazari; Gert Wiese; Mark Langridge; Daniel Höche; Sviatlana V. Lamaka; Mikhail L. Zhelud...
• Keywords: Constant (computer programming); Time constant

Abstract Electrochemical impedance spectroscopy measurements were performed to study the evolution of surface condition, which related to the high frequency time constant of Mg, in 0.05 M NaCl solution at three different pH. Based on the assumption that the high frequency time constant originates solely from the surface film, the thickness of MgO film was calculated via fitting EIS results. The deduced results were compared with the actual surface condition, characterized by transmission electron microscopy and local measurements. The results verified that the time constant at the high frequency range originates from the barrier properties of the surface film.