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Electrochemical characterization of Ni 47.7 Ti 37.8 Nb 14.5 shape memory alloy in artificial saliva
Author(s) -
Mareci D.,
Chelariu R.,
Cailean A.,
Sutiman D.
Publication year - 2012
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.201106337
Subject(s) - materials science , alloy , corrosion , dielectric spectroscopy , shape memory alloy , polarization (electrochemistry) , nickel titanium , electrochemistry , metallurgy , anode , pitting corrosion , intermetallic , electrode , chemistry
Electrochemical corrosion behaviour of the studied Ni 47.7 Ti 37.8 Nb 14.5 (NiTiNb) shape memory alloy was investigated for dental applications. An equiatomic NiTi alloy was used in some tests as reference material. Electrochemical techniques such as anodic potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy (EIS) were employed. Experiments were carried out using artificial saliva. Very low passive current densities were obtained from the anodic polarization curve, indicating a typical passive behaviour for NiTiNb alloy. Over the surface of the NiTiNb alloy uniform corrosion appears, while in case of the NiTi alloy surface pitting corrosion is developed. The role that Nb plays as an alloying element is by increasing the resistance of NiTi alloy to localized corrosion. The EIS results exhibited high impedance values (order of 10 6 Ω cm 2 ) obtained from medium to low frequencies which are indicative of the formation of a highly stable passive film on NiTiNb alloy in the artificial saliva.