Influence of silicon content on the microstructure, mechanical and tribological properties of magnetron sputtered Ti–Mo–Si–N films

• Ti–Mo–Si–N films were deposited by reactive magnetron sputtering.
• Hardness of Ti–Mo–Si–N film (5.0 at.% Si) reached a maximum value of 34.5 GPa.
• Addition of Si (<5.0 at.% Si) led to the increase of fracture toughness.
• The films (3.1–5.0 at.% Si) were found to be optimized for wear resistance tools.

Ti–Mo–Si–N films with various Si content (0–17.2 at.%) were deposited by reactive magnetron sputtering and the effects of Si content on the microstructure, mechanical and tribological properties of Ti–Mo–Si–N films were investigated. The results showed that the face-centered cubic (fcc) interstitial solid solution of Ti–Mo–Si–N was formed by dissolution of Si into Ti–Mo–N lattice with the Si content in the range of 3.1–5.0 at.%. With a further increase in Si content, the films consisted of fcc-Ti-Mo-Si-N and amorphous Si3N4 phases. The hardness and fracture toughness of Ti–Mo–Si–N films first increased and then decreased with the increase of Si content and the highest values were 34.5 GPa and 2.6 MP m1/2, respectively, at 5.0 at.% Si. The average friction coefficient and wear rate of Ti–Mo–Si–N films first decreased and then increased with the increase of Si content and the lowest values were 0.35 and 7.8 × 10−8 mm3/Nmm, respectively, at 5.0 at.% Si.