The electrochemical surface modification of nitinol for inhibition of nickel eliminationстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 11 ноября 2019 г.
Аннотация:Nitinol, an alloy with a shape memory effect, is used in many high-tech developments, in particular in medicine as self-expanding material for vascular endoprostheses, stents, etc. However, a high nickel content in the alloy may be undesirable for biocompatibility and therefore requires the use of certain processing products to reduce the rate of formation of Ni2+ as a result of corrosion processes in the presence of alloy with body tissues. To solve this problem, the possibilities of Nitinol electrochemical treatment based on the different rates of dissolution of the alloy components from the surface layer were investigated. The processes of potentiostatic etching of NiTi in sulphate solutions, which provide selective dissolution of one alloy component and accumulation of another one in the surface layer, have been investigated. Using the polarization curves methods and the electrochemical impedance spectroscopy, it has been discovered. The possibility of selective etching of nickel from the surface layer of Nitinol with the simultaneous formation of titanium dioxide is shown. The high insulating properties of TiO2 film formed on the alloy surface as a result of oxidation at a controlled potential, inhibits the release of nickel from the surface layer and the accumulation of Ni2+ ions in a corrosive, like the physiological solution.
Keywords: Nitinol, selective dissolution, passivation, impedance, protection