Abstract
The paper reports on the effect of Cu content in the Al-Cu-N film on its antibacterial activity and mechanical properties. The Al-Cu-N films were prepared by reactive magnetron sputtering from composed Al/Cu targets using a dual magnetron.
The antibacterial activity of Al-Cu-N films was tested on the killing of Escherichia coil bacteria. Mechanical properties of Al-Cu-N films were determined from the load vs. displacement curves measured by a Fischerscope H 100 microhardness tester.
Mechanical properties were controlled by (i) the Cu content in the film and (ii) the energy Ei delivered to growing film by bombarding ions and fast neutrals. Correlations between the energy Ei, the content of Cu in the Al-Cu-N film and its mechanical and antibacterial properties were investigated in detail.
It was found that (1) Al-Cu-N films with Cu content ranging from similar to 2 to similar to 12 at% exhibit (i) high hardness H ranging from similar to 15 to similar to 23 GPa, (ii) high ratio H/E* }= 0.1, (iii) high elastic recovery W-e }= 60%, (iv) compressive macrostress (sigma < 0) and (v) enhanced resistance to cracking and (2) the Al-Cu-N films with 7 at% Cu exhibit 100% efficiency of killing E-k of E. coli bacteria on their surface both in the daylight and in the dark. It means that the Al-Cu-N films sputtered under ion bombardment are three-functional antibacterial/flexible/protective films.
Both the mechanical and antibacterial properties of sputtered Al-Cu-N films are described in detail. (C) 2015 Elsevier B.V. All rights reserved.