Antibacterial Property of Cu Modified Stainless Steel by Plasma Surface Alloying

Stainless steel (SS) is not recommended to be used in hospital environments for work surfaces and door furniture due to the lack of antibacterial properties. To this end, a novel SS surface modified layer with both a quick bacterial killing rate and relatively thick has been obtained by plasma surface alloying with Cu. The microstructure, elements distribution and phase identification were analyzed by SEM, GDS, XRD and XPS. A spread plate method was adopted for evaluation of antibacterial property of specimens against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The experimental results demonstrate that the surface modified layer with the thickness of about 26 μm is uniform and dense. The layer is mainly composed of a mixture of pure Cu, expanded austenite phase and a few Fe3O4 phase. The Cu modified layer exhibits excellent antibacterial effects against E. coli and S. aureus within 1 h. No viable E. coli and S. aureus was found after 3 h (100% killed). The modified layer is relatively thick, hence it is expected that the Cu modified SS will have a durable antibacterial function.