The microstructure and mechanical properties of Ti(CoCr)N films produced by DC magnetron sputtering

Titanium nitride (TiN) thin films have excellent physical and chemical properties, and are widely used as cutting tools, drills and die protective coatings. However, their limited hardness and corrosion resistance caused by the rough, loose, columnar structure will affect its application in extreme environments. TiN films with refined grains and nanostructure might solve this problem. In this paper, Co and Cr atoms were doped into TiN film to tailor its structure. The effects of Co and Cr content on the Ti(CoCr)N film structure, mechanical properties and corrosion resistance were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), microhardness tester and electrochemical corrosion tester. The results show that Co and Cr doping can disturb the columnar growth of TiN films, and lead to refinement of TiN grains. Compared to TiN films without Co and Cr doping, the hardness of Ti(CoCr)N with 2.7 at.% Co and 1.9 at.% Cr increases by about 37% to 31.3 GPa. And Ti(CoCr)N films with 2.7 at.% Co and 1.9 at.% Cr have the best corrosion resistance.