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.

Keywords:

• Nanocomposites
• Magnetron sputtering
• Chromium nitride
• Microstructure
• Nanoindentation
• Antibacterial property
• Phase stability

The authors acknowledge the support and encouragement from Dr M. Vijayalakshmi, AD, Physical Metallurgy Group, Dr T. Jayakumar, Director, Metallurgy and Materials Group and Mr S. C. Chetal, Director, Indira Gandhi Centre for Atomic Research, Kalpakkam.