Micro-Tensile Strain on the Corrosion Performance of Diamond-like Carbon Coating

Seung-Hwan Lee, Jung-Gu Kim, Heon-Woong Choi, Kwang-Ryeol Lee 

Hydrogenated diamond-like carbon films (a-C:H DLC) were deposited on STS 304 substrate for the fabrication of vascular stents by means of the r.f. plasma-assisted chemical vapor deposition (r.f.PACVD) technique. This study provides reliable and quantitative data for the assessment of the effect of strain on the corrosion performance of DLC coated systems in the simulated body environment obtained through electrochemical technique (potentiodynamic polarization test and electrochemical impedance spectroscopy) and surface analysis (scanning electron microscopy). The electrolyte used in this test was 0.89 % NaCl solution at PH 7.4 and 37^oC. It was found that the corrosion resistance of the plastically deformed DLC coating was insufficient for use as a protective film in a corrosive body environment. This is due to the increase in the delamination area and degradation of the substrate's corrision properties with increasing tensile deformation.