AFM, RBS and tribological properties of WC/WS2 nanostructures after 1.5 MeV Nb+ implantation

The purpose of this study was to evaluate the impact of Nb+ ion implantation in WC/WS2 nanostructures and their tribological properties. The films were deposited on silicon and stainless-steel substrates by DC and RF magnetron sputtering at 400 °C. Different concentrations for sputtering of the WC targets were used while the concentration for WS2 was maintained constant for all the deposition processes. Nb ion implantation with an energy of 1.5 MeV and a dose of 6 × 1014 ions/cm2 at room temperature was done at the 3 MV Tandetron™ accelerator from “Horia Hulubei” National Institute for Physics and Nuclear Engineering – IFIN-HH. The topography of the samples was analyzed by atomic force microscopy (AFM). Rutherford backscattering spectrometry (RBS) investigations gave information regarding stoichiometry and thicknesses of the coatings while tribological properties were studied using a pin–on–ball tribometer before and after Nb ion implantation. We have found that after the Nb implantation the values measured for the coefficient of friction were lower as compared to the unimplanted samples thought to be due to the discrete amorphization sites which could be produced at this lower fluence by energy deposition through elastic and inelastic collisions.