Structure, mechanical and tribological properties of Ti-doped amorphous carbon films simultaneously deposited by magnetron sputtering and pulse cathodic arc

Abstract

In this paper, the structure as well as tribological properties of amorphous carbon (a-C) films modified by titanium doping (a-C:Ti) were examined. The a-C:Ti films were deposited by simultaneously using use of pulse cathodic carbon arc technique and with direct current Ti magnetron sputtering. Structure and surface morphology of the a-C and a-C:Ti films were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy. Friction parameters of the films have been studied under the condition of dry sliding using a “sphere-plane” method. Under the effect of Ti doping, there was an increase in the friction coefficient of the a-C:Ti films from 0.17 up to 0.21 vs. 0.14 for a-C film. In contrast, the counterbody wear rate was 2.2–3.8 times lower in the case of the a-C:Ti films compared with that of the a-C film, which is attributed to the changes in the a-C:Ti films with respect to their phase composition, surface morphology and microhardness under the action of Ti. The study results of this work show that it is possible to obtain hard a-C:Ti films with good enhanced wear resistance by doping an optimal amount of Ti.