Influence of carbon content on the microstructure and tribological properties of TiN(C) coatings in water lubrication

► TiN(C) coatings were deposited using unbalance magnetron sputtering. ► The TiN bonds were changed to Ti(CN), CN, CN and CC bonds. ► The hardness of TiN(C) coatings decreased linearly with the C content. ► The TiN(C) coatings deposited at 3 A displayed excellent mechanical properties.