CARBONACEOUS SURFACE-LAYERS DEPOSITED ON TIN COATINGS BY ION-IMPLANTATION

TiN coatings deposited by physical vapor deposition have been subjected to a postdeposition treatment involving beam line implantation with 80-keV C+ ions at doses between 1 X 10(17) and 3 X 10(17) ions/cm2. Rutherford backscattering spectrometry measurements showed Gaussian-like implantation-depth profiles extending towards the surface which was found to be covered with carbon. The carbonaceous surface layer was characterized by Raman spectroscopy revealing the typical band features of diamondlike carbon. Simulations of the carbon depth profile indicate that the opaque carbon layer was formed from carbon in excess of the implanted dose. Further experiments suggest that the carbon layer resulted from an ion-beam-assisted deposition process. Fretting wear tests demonstrated lower friction and improved wear resistance of the TiN covered with the diamondlike carbon layer in comparison with as-deposited TiN.