engleski

Surface and electrochemical characterization of IrTi-oxide coatings: Towards the improvement of radiopacity for coronary stent applications

Thin IrxTi(1-x)-oxide coatings (x=0, 0.2, 0.4, 0.6, 0.8 and 1) were formed on Ti substrates and commercial 316L stainless steel (SS) coronary stents employing a simple thermaldeposition method. Electrochemical and surface-characterization techniques were used to investigate the surface topography/morphology and chemical composition of the coatings, their electrochemical properties, and radiopacity. These properties were found to highly depend on the coating composition ; however, no particular composition-dependent trend was observed. All the coatings were found to be stable under the experimental conditions employed in the research. The electrochemical behaviour of the Ir-containing coatings was governed mostly by the pseudo-capacitive response of the coating and the coating/electrolyteinterface. The absence of the low-frequency resistive component of the impedance responseindicated a very high corrosion resistance of the coatings. SS coronary stents modified by IrxTi(1-x)-oxide coatings were found to be more radiopaque than the bare (naked) SS stent. The Ir0.4Ti0.6-oxide coating showed to be the most uniform, the most corrosion resistant and the most radiopaque coating.

iridium; oxide coatings; radiopacity; stents; titanium

nije evidentirano