Silva R A, Silva I P, Rondot B
Instituto Superior de Engenharia do Porto/ISEP-CIEA, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal.
J Biomater Appl. 2006 Jul;21(1):93-103. doi: 10.1177/0885328206056378. Epub 2006 Jan 27.
Self-expandable nitinol (nickel-titanium) alloys and 316L stainless steel are the most commonly used materials in the production of coronary stents. However, tantalum (Ta) has already been used to make stents for endovascular surgery and may constitute an alternative to other materials because of its better electrochemical performance, namely its higher corrosion resistance, as well as its radio-opacity. The characterization of wet polished, chemically polished, wet polished anodized, and chemically polished anodized Ta electrodes has been performed in a 0.15 M NaCl solution (simulated body fluid) using Ucorr = f(t) measurements, anodic polarizations, capacity measurements, anodic oxidations, and atomic force microscopy (AFM) imaging. Anodic polarization curves have shown that the abnormal current density peak with a maximum value around 1.65 V (critical applied potential, Uc) disappeared for the anodized electrodes indicating a probable relationship between the surface states and the film growth. These results are confirmed by capacity measurements. The behavior of wet polished and chemically polished electrodes during anodic oxidations seemingly indicated that for these particular treatments the film growth is different. The AFM images and roughness measurements have shown that chemical polishing produced smoother electrodes, a fact probably related to the differences in film growth.
自膨胀镍钛合金和316L不锈钢是冠状动脉支架生产中最常用的材料。然而，钽（Ta）已被用于制造血管内手术支架，由于其具有更好的电化学性能，即更高的耐腐蚀性以及射线不透性，可能成为其他材料的替代品。在0.15 M NaCl溶液（模拟体液）中，使用Ucorr = f(t)测量、阳极极化、电容测量、阳极氧化和原子力显微镜（AFM）成像对湿抛光、化学抛光、湿抛光阳极氧化和化学抛光阳极氧化的钽电极进行了表征。阳极极化曲线表明，阳极氧化电极的异常电流密度峰值（最大值约为1.65 V，临界施加电位，Uc）消失，这表明表面状态与膜生长之间可能存在关系。电容测量证实了这些结果。湿抛光和化学抛光电极在阳极氧化过程中的行为似乎表明，对于这些特定处理，膜生长是不同的。AFM图像和粗糙度测量表明，化学抛光产生的电极更光滑，这一事实可能与膜生长的差异有关。
