Deposition of silver and titanium co-doped diamond-like carbon films by magnetron sputtering

The aim of this study was to investigate the effects of silver and titanium co-doping on the microstructure and properties of non‑hydrogenated diamond-like carbon (DLC) films deposited via direct current magnetron sputtering. Doping levels were controlled by varying the shield opening above a silver‑titanium (50/50 at.%) target. The films were characterized using energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, atomic force microscopy, nanoindentation, and surface wetting. Co-doped metal content ranged from 2.0 at.% and 0.3 at.% to 8.2 at.% and 2.9 at.% for Ag and Ti, respectively (XPS data). Moderate doping improved hardness and elastic modulus, while higher levels induced graphitization of the doped-DLC films. Tunable friction coefficients and wettability were observed, suggesting potential applications in wear-resistant and biocompatible coatings. XPS analysis revealed the formation of carbon oxide and titanium oxide bonds with no pronounced existence of titanium carbide in the doped films. Increasing Ag and Ti content enhanced the surface roughness and promoted cluster formation in the films. This study provides valuable insights into the synergistic effects of Ag and Ti in DLC films, highlighting their versatility for advanced functional coatings.