The effect of Cu content on the microstructures, mechanical and antibacterial properties of Cr–Cu–N nanocomposite coatings deposited by pulsed DC reactive magnetron sputtering

The nanocomposite Cr–Cu–N thin films with Cu content ranging from 1.6 to 24.3 at.% have been deposited by a bipolar asymmetric pulsed DC reactive magnetron sputtering system. A strong CrN (200) texture is found for each coating. The columnar structure was replaced by a dense and compact morphology when the coating contained more than 8.2 at.% Cu. An unusual hardness enhancement is observed on the coating with 15.7 at% Cu, which is possibly due to its grain refinement effect. For the coating containing 15.7 at.% Cu, a combination of high hardness, low coefficient of friction and good antibacterial properties are achieved. The Cr–Cu–N nanocomposite thin film developed in this study with sufficient hardness and antibacterial abilities can be used as a promising candidate to deposit on the surfaces of medical apparatus and food processing equipments.