SURFACE CHARACTERIZATION AND ELECTROCHEMICAL-BEHAVIOR OF NITROGEN-IMPLANTED AND CARBON-IMPLANTED TITANIUM

Owing to their combination of metallic and covalent properties, TiN and TiC are used as coating materials. In this work thin layers (layer thickness about 10 nm) of TiN and TiC were prepared by low-energy ion implantation (3 keV N2+, 4 keV C2H4+) into Ti. The change in surface composition as a function of ion dose was followed by XPS. The electrochemical behaviour was studied in an electrochemical cell attached to the surface equipment; therefore no surface oxidation due to air contact took place. TiN and TiC revealed a stability up to 1.5 and 1.0 V respectively. Above these potentials oxidation to TiO2 and N2 in the case of TiN and to TiO2, CO2 and CO in the case of TiC occurred. The gaseous oxidation products were dissolved in the oxide layer and influenced its properties.