Corrosion resistance for biomaterial applications of TiO2 films deposited on titanium and stainless steel by ion-beam-assisted sputtering
✍ Scribed by Pan, J. ;Leygraf, C. ;Thierry, D. ;Ektessabi, A. M.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 368 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
The high corrosion resistance and good biocompatibility of titanium and its alloys are due to a thin passive film that consists essentially of titanium dioxide. There is increasing evidence, however, that under certain conditions extensive titanium release may occur in vivo. An ion-beam-assisted sputtering deposition technique has been used to deposit thick and dense TiO 2 films on titanium and stainless steel surfaces. In this study, using the following measurements these TiO 2 films have been investigated in a phosphatebuffered saline solution:
(1) open-circuit potential versus time of exposure, (2) electrochemical impedance spectroscopy, (3) potentiodynamic polarization, and (4) Mott-Schottky plot. A higher electrical film resistance, lower passive current density, and lower donor density (in the order of 10 15 cm -3 ) have been measured for the sputter-deposited oxide film on titanium in contrast to the naturally formed passive oxide film on titanium (donor density in the order of 10 20 cm -3 ). The improved corrosion protection of the sputter-deposited oxide film can be explained by a low defect concentration and, consequently, by a slow mass transport process across the film. As opposed to TiO 2 on titanium, a deviation from normal n-type semiconducting Mott-Schottky behavior was observed for TiO 2 on stainless steel.