Evaluation of phase, composition, microstructure and properties in TiC/a-C:H thin films deposited by magnetron sputtering

Titanium carbide/amorphous-carbon (TiC/a-C:H) nanocomposite coatings deposited by pulsed unbalanced reactive magnetron sputtering have been investigated in terms of structure, chemical and phase composition by AFM, TEM, XPS and XRD analyses. Subject to total carbon content, metallic titanium, titanium carbide and amorphous-carbon phases were found in the deposited coatings, which contributed to the observed microstructures and morphologies. The specific resistivity of nanocomposite coatings scales up with increasing amount of matrix-forming carbon. Hardness profiles of the different compositions revealed that nearly stoichiometric TiC films with average crystallite size of 70 nm exhibit the maximum hardness, whereas the lowest friction coefficient (μ<0.1) was found in films rich in amorphous-carbon and containing smaller TiC nanocrystallites (〈d〉 ∼ 10 nm).