Effects of Cr concentrations on the microstructure, hardness, and temperature-dependent tribological properties of Cr-DLC coatings

Cr doped diamond like carbon (Cr-DLC) coatings were deposited by using a combined system consisting of middle frequency (MF) magnetron sputtering and ion plating. The structure and properties of the undoped and Cr-doped DLC coatings were analyzed by various testing, such as Raman, XPS, hardness and temperature-dependent frictional wear testing. The results showed that Cr-DLC coatings with low Cr concentration was a effective protective coating containing Cr–C nanometer grains, whose mechanical properties were obviously improved, such as, residual stress and cohesive strength, and still kept good wear resistance at the ambient temperature of 400 °C.