Microstructural, nanomechanical and antibacterial properties of magnetron sputtered nanocomposite thin films of CrN/Cu

Abstract

Synthesis of nanocomposite thin films of CrN/Cu on (100) Si and titanium modified stainless steel (D-9 alloy) substrates by pulsed magnetron sputtering from a composite target of Cr–Cu using sputtering gas mixture of argon and nitrogen is investigated. X-ray diffraction analysis of the films deposited at 773 K and 10 sccm of nitrogen flowrate indicated that the films are nanocrystalline and biphasic (fcc CrN and fcc Cu). The films showed a peak hardness of ∼15 GPa and a Young’s modulus of ∼200 GPa for those with a copper content of 15·1 at-%, and these values were found to decrease significantly with a Cu content of ⩾18·4 at-%. The evaluation of the antibacterial activity as a function of copper content in the range of 15·1–38·5 at-% indicated excellent antibacterial properties for CrN/Cu films with the copper content of 18·4 at-%. The phase stability of CrN of the nanocomposite is also discussed in relation to pure CrN thin films.