The effect of nitrogen ion implantation on the surface properties of Ti6Al4V alloy coated by a carbon nanolayer

The ion beam assisted deposition (IBAD) method was chosen for preparing a carbon thin film with a mixing area on a substrate of Ti6Al4V titanium alloy. Nitrogen ions with energy 90 keV were used. These form a broad ion beam mixing area at the interface between the carbon film and the substrate. We investigated the chemical composition by the glow discharge optical emission spectroscopy (GD-OES) method and the phases by the X-ray diffraction (XRD) method. The measured concentration profiles indicate the mixing of the carbon film into the substrate, which may have an effect on increasing the adhesion of the deposited film. The nanohardness and the coefficient of friction were measured. We found that the modified samples had a markedly lower coefficient of friction even after damage to the carbon film, and they also had higher nanohardness than the unmodified samples. The increased nanohardness is attributed to the newly created phases that arose with ion implantation of nitrogen ions.