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Nitinol: Tubing versus sputtered film – microcleanliness and corrosion behavior
Author(s) -
Wohlschlögel Markus,
Lima de Miranda Rodrigo,
Schüßler Andreas,
Quandt Eckhard
Publication year - 2016
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.33449
Subject(s) - materials science , corrosion , metallurgy , composite material
Corrosion behavior and microcleanliness of medical‐device grade Nitinol tubing (Ni x Ti 1‐ x , x = 0.51; outer diameter 7 mm, wall thickness 0.5 mm), drawn from various ingot qualities, are compared to the characteristics of sputtered Nitinol film material (Ni x Ti 1‐ x , x = 0.51; thickness 50 µm). Electropolished tubing half‐shell samples are tested versus as‐received sputtered film samples. Inclusion size distributions are assessed using quantitative metallography and corrosion behavior is investigated by potentiodynamic polarization testing in phosphate‐buffered saline at body temperature. For the sputtered film samples, the surface chemistry is additionally analyzed employing Auger Electron Spectroscopy (AES) composition‐depth profiling. Results show that the fraction of breakdowns in the potentiodynamic polarization test correlates with number and size of the inclusions in the material. For the sputtered Nitinol film material no inclusions were detectable by light microscopy on the one hand and no breakdowns were found in the potentiodynamic polarization test on the other hand. As for electropolished Nitinol, the sputtered Nitinol film material reveals Nickel depletion and an Oxygen‐to‐Titanium intensity ratio of ∼2:1 in the surface oxide layer, as measured by AES. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1176–1181, 2016.