Revisiting the effects of low-concentration hydrogen in NiTi self-expandable stents.

Superelastic NiTi is widely used in self-expandable transcatheter devices such as cardiovascular stent, neuro thrombectomy retriever and aortic valve scaffold. Hydrogen at a concentration of C < 100 wppm is almost always contained in these devices due to the chemical surface treatments during production. The survey of hydrogen concentrations in 9 commercial stent samples show H concentrations values ranging from 6 to 55 wppm.

On the High Sensitivity of Corrosion Resistance of NiTi Stents with Respect to Inclusions: An Experimental Evidence.

In this study, the electrochemical breakdown potentials ( ) of NiTi stents were assessed in correlation to their nonmetallic inclusion fractions in the extra low inclusion (ELI) range (inclu.% < 1% in area fraction, average size <39 μm). Quantitative investigations were performed to study the role of nonmetallic inclusions during pitting corrosion.

In vitro degradation behavior of Fe-20 Mn-1.2C alloy in three different pseudo-physiological solutions.

High manganese austenitic steels such as Fe-20Mn-1.2C alloys are among the most promising candidates for biodegradable stents applications due to their high strength, high ductility and their chemical composition. In the current work, 14 day static in-vitro tests were performed in controlled atmosphere to assess the degradation behavior in three common pseudo-physiological solutions, i.

Nanoindentation and XPS Studies of Titanium TNZ Alloy after Electrochemical Polishing in a Magnetic Field.

This work presents the nanoindentation and XPS results of a newly-developed biomaterial of titanium TNZ alloy after different surface treatments. The investigations were performed on the samples AR (as received), EP (after a standard electropolishing) and MEP (after magnetoelectropolishing). The electropolishing processes, both EP and MEP, were conducted in the same proprietary electrolyte based on concentrated sulfuric acid.