Tribological and Electrical Properties of Chromium-Doped Carbon Films Fabricated by Unbalanced Magnetron Sputtering for Medical Stents

Chromium-doped carbon (Cr: C) films were fabricated by using unbalanced magnetron sputtering with chromium (Cr) and graphite (C) targets. We investigated the structural, tribological, and electrical properties of the Cr: C films fabricated with various target power densities. The surface of all the Cr: C films was smooth and uniform, and the cross section showed a more compact and clear columnar structure as the target power density increased. The root mean square surface roughness increased and the contact angle on the film surface increased with the increase in target power density. Furthermore, the hardness and elastic modulus of the Cr: C films showed improvements, while the resistivity decreased with the increase in target power density. These results are associated with the ion bombardment and resputtering owing to the effects of the applied target power density.