Antibacterial properties of Cu containing complex concentrated alloys

Abstract

The present work demonstrates the antibacterial properties of CoCrCuNi and CoCrCuFeNi complex concentrated alloys (CCAs) against the Escherichia coli bacteria. A non-Cu-containing CoCrFeNi alloy has also been investigated to gain a comprehensive understanding of the effect of Cu addition on the antibacterial properties. All the alloys have been studied with reference to 316 L stainless steel and pure Cu. The alloys' phase structure, wettability, bacterial adhesion studies, and apatite forming ability are analyzed. Antibacterial efficiency of CoCrCuNi and CoCrFeNiCu are 99.99% and 98.11%, respectively which are superior to CoCrFeNi (40%) and SS316L. The Cu ion release mechanism facilitated the improved antibacterial efficiency in the Cu-containing CCAs. The CCAs in the study showed apatite formation on the surface of the coupons. However, the Cu-containing alloys showed high surface degradation with selective oxidation and loss of the copper-rich phase in CoCrCuFeNi and CoCrCuNi, respectively, which can be attributed to the phase separation in these CCAs. The Vickers microhardness of the alloys is in the range of 130–145 VHN. The results of this work pave the way for further development of these alloys for several antibacterial applications.