On the Ni-Ion release rate from surfaces of binary NiTi shape memory alloys

0485204 - ÚFM 2019 RIV NL eng J - Journal Article
Ševčíková, J. - Bártková, Denisa - Goldbergová, M. - Kuběnová, Monika - Čermák, Jiří - Frenzel, J. - Weiser, Adam - Dlouhý, Antonín
On the Ni-Ion release rate from surfaces of binary NiTi shape memory alloys.
Applied Surface Science. Roč. 427, JAN (2018), s. 434-443. ISSN 0169-4332. E-ISSN 1873-5584
R&D Projects: GA ČR(CZ) GA15-16336S
Institutional support: RVO:68081723
Keywords : NiTi bio-compatibility * Ni-ion release * NiTi surface passivation * Hydrogen soaking * Scanning transmission electron microscopy
OECD category: Materials engineering
Impact factor: 5.155, year: 2018

The study is focused on Ni-ion release rates from NiTi surfaces exposed in the cell culture media and human vascular endothelial cell (HUVEC) culture environments. The NiTi surface layers situated in the depth of 70 µm below a NiTi oxide scale are affected
by interactions between the NiTi alloys and the bio-environments. The finding was proved with use of inductively coupled plasma mass spectrometry and electron microscopy experiments. As the exclusive factor controlling the Ni-ion release rates was not only thicknesses of the oxide scale, but also the passivation depth, which was two-fold larger. Our experimental data strongly suggested that some other factors, in addition to the Ni concentration in the oxide scale, admittedly hydrogen soaking deep below the oxide scale, must be taken into account in order to rationalize the concentrations of Ni-ions released into the bio-environments. The suggested role of hydrogen
as the surface passivation agent is also in line with the fact that the Ni-ion release rates considerably decrease in NiTi samples that were
annealed in controlled hydrogen atmospheres prior to bio-environmental exposures.

Permanent Link: http://hdl.handle.net/11104/0284210