Cross-section transmission electron microscopy characterization of the near-surface structure of medical Nitinol superelastic tubing.
The application of Nitinol in a wide variety of medical implants is progressively increasing because of its unique mechanical properties, durability and biocompatibility. However, as Nitinol consists of about 50 at.% of toxic Ni, certain applications are still hindered by the concern of free Ni release in the surrounding tissue. The latter is controlled by the structure of near-surface layers and can be strongly affected by various surface treatments. A proper application of advanced cross-section sample preparation techniques allows us to characterize the Nitinol near-surface structure down to the nanoscale by means of transmission electron microscopy (TEM). Elemental maps of the Ti, O and Ni distribution, concentration profiles, quantification of composition as well as atomic resolution images at the surface of a Nitinol tubing are presented and the results obtained with different sample preparation and analytical characterization techniques are compared. In addition to a strong decrease of Ni towards the surface of the oxide layer and a Ti depleted layer underneath the oxide, also a possible transformation from TiO to TiO(2) is documented.
Potapov
Pavel L
PL
EMAT, University of Antwerp, Antwerp, Belgium.
Tirry
Wim
W
Schryvers
Dominique
D
Sivel
Valerie G M
VG
Wu
Meng-Yue
MY
Aslanidis
Dimitri
D
Zandbergen
Henny
H
D000497:Alloys / Q000737:chemistry / Q000633:toxicity; D001672:Biocompatible Materials / Q000737:chemistry / Q000633:toxicity; D004548:Elasticity; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008854:Microscopy, Electron; D009532:Nickel / Q000737:chemistry / Q000633:toxicity; D010084:Oxidation-Reduction; D019736:Prostheses and Implants; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
D000497:Alloys; D001672:Biocompatible Materials; C013616:nitinol; D009532:Nickel; D014025:Titanium