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Effects of Hf content and immersion time on electrochemical behavior of biomedical Ti‐22Nb‐ x Hf alloys in 0.9% NaCl solution
Author(s) -
Wang B. L.,
Zheng Y. F.,
Zhao L. C.
Publication year - 2009
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200805120
Subject(s) - corrosion , dielectric spectroscopy , materials science , alloy , electrochemistry , immersion (mathematics) , polarization (electrochemistry) , analytical chemistry (journal) , electrical impedance , metallurgy , chemistry , electrode , chromatography , mathematics , pure mathematics , electrical engineering , engineering
The aim of this study was to investigate the effects of Hf content and immersion time on the electrochemical corrosion behavior of the Ti‐22Nb‐ x Hf ( x = 0, 2, 4, and 6 at%) alloy samples in 0.9% NaCl solution at 37 °C and neutral pH range, utilizing the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. From the polarization curves, all these alloys exhibited typical passive behavior, which was indicated by a wide passive region without the breakdown of the passive films and low corrosion current densities. In addition, the values of the corrosion current densities and passive current densities decreased with increase in the Hf content. The EIS results, fitted by R S ( Q P R P ) model, exhibited capacitive behavior (high corrosion resistance) with phase angles closed to −80° and high impedance values at low and medium frequencies, indicating the formation of a highly stable film on these alloys in the test solution. The resistance of the passive films improved with increase in the Hf content and immersion time. All these observations suggested a more noble electrochemical behavior of the Ti‐22Nb‐ x Hf alloys compared to the Ti‐Nb binary alloy.