Raman Analysis of Diamond-Like Carbon Films Deposited onto Corrosion Resistant Alloys Used for Coronary Stent Fabrication
The structure of diamond-like carbon thin films prepared by radio frequency chemical vapor deposition onto the surface of different corrosion resistant alloys (304, 316L and Iconel 617) used for coronary stent fabrication was investigated by Raman spectroscopy excited by visible (488 nm) and near-infrared (785 nm) light. The effect of electrochemical polishing of the alloy surface and that of Ar+ ion pre-treatment on the structure of the forming film was also studied in case of substrate made of 316L material. It was found that in spite of simultaneous preparation the character of the formed amorphous carbon films depends on the type of the alloy. The layer developed on the surface of Fe-rich stainless steels (316L and 304) showed the most diamond-like character, while the Ni-rich Inconel alloy promoted the formation of layer with high graphitic sp2 cluster content. The Ar+ pre-treatment enhanced the adhesion and the diamond-like properties of the film while the electrochemical polishing was found to be unfavorable concerning the diamond-like character of the layer.
J. Gyulai and P.J. Szabó
M. Veres et al., "Raman Analysis of Diamond-Like Carbon Films Deposited onto Corrosion Resistant Alloys Used for Coronary Stent Fabrication ", Materials Science Forum, Vols. 537-538, pp. 277-284, 2007