Characteristics of Palladium Carbide Thin Films Prepared by Unbalanced Magnetron Sputtering

We prepared palladium-doped carbon or palladium carbide (PdC) thin films using an unbalanced magnetron sputtering method. Palladium was used as the doping material in carbon thin films to facilitate the application of contact strips in an electric railway. The structural, surface, tribological, and electrical properties of the fabricated PdC films with various Pd target power densities from 2 W/cm 2 to 5 W/cm 2 for varying Pd doping ratio were investigated. All PdC films exhibited a uniform and smooth surface. Moreover, the hardness and elastic modulus properties of PdC films were found to be improved, and the resistivity and sheet resistance were decreased with the increase of power density in Pd target. It was also found that the critical load value of PdC film increased as the adhesion property increased. These results are associated with the nano-sized crystalline PdC phase and sp 2 clusters in carbon networks, which are increased by ion bombardment, which is in turn enhanced with the increase of power density in Pd target. As a result, the increase in sp 2 clusters containing PdC in carbon films is attributed to improvements in the adhesion, hardness, and electrical properties.