Wear resistant multiphase compound of Ti(C, O, N)/a-C:H nano composite film

Multiphase Ti(C, O, N)/a-C:H thin film was synthesized by reactive magnetron sputtering of TiC in controlled CH4, O2 and N2 media. The resultant chemical structure and composition of this complex phase are governed by the substrate temperature. At a lower substrate temperature of 40 °C, hydrogenated amorphous carbon (a-C:H) with defected aromatic sp2 domains was dominated with titanium oxide and titanium oxynitride phases and small fraction of nanocrystalline TiCx grains was observed. With an increase in substrate temperature to 200 °C, carbon concentration is increased which existed in a-C:H and nanocrystalline TiCx phase while the amount of titanium, oxygen and nitrogen are decreased. Interestingly, spi domains in the film were not observed at this substrate temperature. However, at substrate temperatures 300 and 400 °C, a-C:H and sp2 domains are further increased but the amount of nanocrystalline TiCx phase decreased. At high temperature, the concentration of elemental titanium, carbon, oxygen and nitrogen are less due to the formation of Ti(C, O, N)/a-C:H and sp2 cluster. Low friction coefficient and exceptionally high wear resistance of this film is derived from the existence of sp2 domains. The absence of this phase in the film showed significantly high friction coefficient and high wear despite the presence of high amount of nanocrystalline TiCx phase.