The influence of crystal structure and the enhancement of mechanical and frictional properties of titanium nitride film by addition of ruthenium

Titanium nitride as a very representative ceramic film has been widely applied in cutting tools. Improvement the toughness and friction property of titanium nitride based films have been a research hotspot. In this paper, ruthenium was added into the titanium nitride brittle matrix and titanium ruthenium nitride composite hard films were synthesized using RF magnetron sputtering system and its crystal structure and room temperature tribological properties were investigated. The results showed that the addition of ruthenium above 1.3 at.% into the face-centered cubic (fcc) titanium nitride matrix exceeded the solid solubility limit and induced other phase of hexagonal close-packed (hcp) ruthenium. Addition of ruthenium into the titanium nitride matrix could enhance the fracture toughness, since it induced much more dislocations and interfaces. Compared with titanium nitride film, the content of adding ruthenium above 0.9 at.% reduced friction coefficient significantly without sacrificing the wear rate.