Diamond-like carbon prepared by pulsed laser deposition with ion bombardment: physical properties

Diamond-like carbon (DLC) and titanium-doped DLC thin films were prepared by unique hybrid system consisting of pulsed laser deposition, ion source (bombardment) and magnetron sputtering. The influence of deposition parameters (ion energies, deposition pressures and magnetron power) on composition and physical properties was studied. Composition and sp(3)/sp(2) ratio were determined by XPS. sp(3)/sp(2) ratio was in the range from 1.4 to 2.2 for undoped DLC and from 3.4 to 4.8 for Ti-DLC. AFM showed that the layers were smooth, but with small amounts of random droplets. The measurements of the contact angle and determination of surface free energy were made for water, diiodomethane and ethylene glycol. Hardness and reduced Young's modulus varied from 20 to 31 GPa and from 182 to 276 GPa, respectively. Film adhesion was determined by scratch test; L-C3 reached 23 N for DLC and 27 N for TiDLC. Optimization of sp(3)/sp(2) ratio, hardness and adhesion to biomedical alloys will advance the DLC coatings usability in the field of implantology.