Atomic layer-deposited Al.sub.2./sub.O.sub.3./sub. coatings on NiTi alloy

0432497 - FZÚ 2015 RIV US eng J - Journal Article
Kei, C.C. - Yu, Y.S. - Racek, Jan - Vokoun, David - Šittner, Petr
Atomic layer-deposited Al₂O₃ coatings on NiTi alloy.
Journal of Materials Engineering and Performance. Roč. 23, č. 7 (2014), s. 2641-2649. ISSN 1059-9495. E-ISSN 1544-1024.
[International Conference on Shape Memory and Superelastic Technologies (SMST 2013). Praha, 21.05.2013-24.05.2013]
R&D Projects: GA ČR(CZ) GA101/09/0702; GA MŠMT(CZ) 7E11058
EU Projects: European Commission(XE) 262806 - SmartNets
Institutional support: RVO:68378271
Keywords : ALD * Al₂O₃ coating * corrosion * NiTi
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 0.998, year: 2014

Atomic layer deposition is introduced as a method suitable for preparation of Al2O3 layers on the surface of NiTi medical devices such as stents because of the excellent thickness control and conformal protective coating on complex structures. The corrosion properties of NiTi plates with Al2O3 coatings of various thicknesses in an environment similar to that occurring in the human body were studied using open circuit potential, potentiostatic electrochemical impedance spectroscopy, and cyclic polarization tests. It shows that the layer thickness plays a key role in the inhibition of corrosion. The thinner layers are more diffuse and make it easier for anodic reaction of passive NiTi with protective TiO2 underneath of Al2O3, while the thicker layers have the barrier effect with local pores initiating pitting corrosion. The results of our electrochemical experiments consistently show that corrosion properties of thick Al2O3 coatings on NiTi plate are inferior compared to the thin layers.
Permanent Link: http://hdl.handle.net/11104/0236891