Ion beam analysis and Raman characterisation of coatings deposited by cosputtering carbon and chromium in a closed field unbalanced magnetron sputter ion plating system

A novel non-hydrogenated a-C coating has been deposited by sputtering carbon and chromium targets in a closed field unbalanced magnetron sputter ion plating system, with a metallic adhesion layer between the substrate and the cosputtered layer. The properties of these new carbon coatings have been previously compared with those of more conventional hydrogenated metalcontaining DLC. Reciprocating and pin-on-disk friction and wear tests have shown that the new carbon coatings have a lower friction coefficient and that their wear resistance is more than one order of magnitude higher than metal-containing hydrogenated DLC coatings. This paper presents an initial study of the composition and structure of these new coatings. Rutherford and Non-Rutherford backscattering of alpha particles and protons are used for studying the stoichiometry and for the determination of impurities. Elastic recoil detection analysis (ERDA) is used for depth profiling of hydrogen. Raman spectroscopy is used to investigate the structure of the different carbonaceous layers.