Microstructure, Mechanical and Tribological Properties of Reactive Magnetron Sputtered Titanium Carbide Coatings

This study describes the correlation between the microstructure, mechanical and tribological properties of Ti1-xCx coatings (with x being in the range of 0-1), deposited by reactive magnetron sputtering from a Ti target in Ar/C2H2 mixtures at ~200 °C. The mechanical and tribological properties were found to strongly depend on the chemical composition and the microstructure present. Very dense structures and high hardness and elastic modulus values, combined with low wear rates, were observed for films with chemical composition close to TiC. X-ray diffraction studies showed that the coating deposited at high C2H2 flow rates composed of randomly oriented TiC crystallites. Morphological investigations by scanning electron microscopy indicate that the morphology is strongly dependent on the carbon content of the coating. Coatings overall composition, and relative phase fraction are investigated using X-ray photoelectron spectroscopy. The presence of free amorphous carbon as DLC was found in the case of the coatings deposited at 43 and 50 sccm of C2H2, where this is not the case for coatings deposited at lower C2H2 flow rates. Both the mechanical properties and tribological