| Title | Electrochemical and microstructural studies of tantalum and its oxide films for biomedical applications in endovascular surgery |
| Publication Type | Journal Article |
| 2002 |
| Authors | Silva, RA, Walls, M, Rondot, B, Da Cunha Belo, M, Guidoin, R |
| Journal | Journal of Materials Science: Materials in MedicineJ. Mater. Sci. Mater. Med. |
| Volume | 13 |
| Issue | 5 |
| Pagination | 495 - 500 |
| Date Published | 2002/// |
| 09574530 (ISSN) |
| article, Atomic force microscopy, body fluid, coronary stent, Corrosion, Corrosion resistance, Current density, Electric Potential, electrochemical analysis, Electrochemical impedance spectroscopy, electrochemistry, electrode, endovascular surgery, Energy gap, film, heart catheterization, hydroxide, Materials science, metal oxide, Metallic films, Microstructure, nitinol, optical density, Oxide films, Polarization, priority journal, simulation, sodium chloride, Stainless steel, structure analysis, Surgery, Tantalum, Tantalum compounds, tantalum oxide, unclassified drug |
| The most popular coronary stents are made of 316L stainless steel and self-expandable Nitinol. Nevertheless, Ta has already been used to make stents for endovascular surgery and may constitute a good alternative to the other materials because of its higher corrosion resistance and radio-opacity property, which may facilitate the follow-up of stent catheterization. The characterization of Ta and its natural passive oxide films has been performed in a 0.15M NaCl solution (simulated body fluid - SBF) using anodic polarizations, electrochemical impedance spectroscopy and photoelectrochemical techniques. Changes in microstructure have been observed by atomic force microscopy (AFM). Polarization curves show the existence of a current density increase between 1.40 and 1.80V. Bode complex plots show that some perturbation of the film occurred in this potential interval which may be associated with a decrease in polarization resistance, Rp, indicating that the film may be less resistant to corrosive attack. Mott-Schottky capacity measurements show that the density of donors, Nd, varies with polarization. The optical band gap, E g, which is equal to 4.1 eV did not show variations in our experiments. The localized formation on the electrode surface, in the above potential interval of a Ta compound (possibly an oxide-hydroxide) was observed by AFM, and this may explain the appearance of the current density peak and capacity behavior at those potentials. © 2002 Kluwer Academic Publishers.
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