Effect of Mo addition on the mechanical and tribological properties of magnetron sputtered TiN films

Ternary-based titanium nitride (TiN) thin films have drawn attention toward rational applications due to their wear resistance, high hardness, and corrosion resistance. The influence of Mo content on the structural, tribo-logical, and mechanical properties of TiN films is reported in this study. The microstructure and elemental composition of the as-deposited TiMoN films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), nanoindentation, and ball-on-disc wear tests. XRD results showed that the as-sputtered TiMoN films consisted of a formation of solid solution of TiN and MoN mixture phases. With 18 at. % of Mo, the me-chanical property of TiMoN films was enhanced, and the film exhibited a high hardness of 28 GPa. Moreover, this addition led to a wear rate of 0.40 and 6.34 x 10-6 mm3/Nm and to lower the friction coefficient to values lower than the corresponding binary TiN film. This was attributed to the multi-phase strengthening and higher (H/E, H3/E2) values, which indicate that the mechanical properties and the wear resistance of TiN can be enhanced by alloying with Mo.