TITLE:
Corrosion Behaviors of Sputtered NiTiCu Shape Memory Films
AUTHORS:
Nan Ye, Xueping Ren
KEYWORDS:
Corrosion, NiTiCu Shape Memory Alloy, Electrochemical Impedance Spectroscopy, NiTiCu Films
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.8 No.2,
January
20,
2020
ABSTRACT: For NiTiCu SMA, the Ni atoms are substituted by Cu atoms, which not only greatly reduce the alloy cost, but also have excellent shape memory effect. Four kinds of shape memory alloy films (Ni49.6Ti50.4, Ni48.2Ti50.4Cu1.4, Ni45.6Ti50.4Cu4, Ni42.7Ti50.4Cu6.9) were prepared using magnetron sputtering. Corrosion behaviors of the four films in phosphate buffered saline (PBS) solutions at 37°C were examined using electrochemical impedance spectroscopy (EIS) method. It was found that the corrosion resistance of the NiTi film is superior to the three NiTiCu films. The EIS data were fitted using a parallel resistance-capacitance (as a constant phase element) circuit associated with the surface oxide film. The thickness of the surface oxide layer of the three NiTiCu films increases with applied potential till 0.8 V, while that of the NiTi film can reach to 1.2 V.