Study On Preparation Of Antibacterial Functional Materials By Copper Implantation Into Martensitic Stainless Steel

This paper presents antibacterial properties of 2Crl3 martensitic stainless steel implanted by Cu ions. The Cu ions are extracted from a metal vapor vacuum arc (MEVVA) with 60~100keV energy and a dose range 0.2-5.0 1017 ions cm-2. Effects of implantation parameters and antibacterial processing parameters on antibacterial properties of stainless steel were analyzed. The surface microstructures, phase composition and Cu ions concentration profile in the implanted layer were examined with glancing X-ray diffraction (GXRD), transmission electron microscopy (TEM) and Auger electron spectrum (AES). The agar plate method was adopted for evaluation of the antibacterial activity of the specimens. By bio-TEM, antibacterial actions on the surface of Cu-implanted stainless steel were observed. Based on phenomena of antibacterial actions, the antibacterial mechanism of Cu-implanted stainless steel was proved up.The results indicate that un-implanted stainless steel has no antibacterial activity, but the implanted specimens have certain antibacterial activity. The saturation dose of corresponding implantation energy is the optimal implantation dose. Stainless steel implanted by saturation dose has good antibacterial activity against Escherichia coli (E. coli). The optimal antibacterial process is a treatment at 500 C for 4h. Stainless steel which was implanted with a dose of 5.0 1017 ions cm-2 at the energy of 1 OOKeV then treated with optimal antibacterial treatment performs excellent antibacterial property against both E. coli and Staphylococcus aureus (S. aureus).Cu exists in the implantation layer as solid solution after stainless steel implanted by Cu ions. But new phases such as Cu9.9Fe0.1, Fe4U3 were formed by antibacterial treatment, the existing forms of Cu become diversity. Antibacterial property of stainless steel attributes to these Cu contained phase and Cu rich phase. All of these new phases are defined as antibacterial phases of antibacterial stainless steel prepared by Cu ions implantation.The antibacterial mechanism of antibacterial stainless steel prepared by Cu ions implantation can be explained as followings: The Cu-rich phase precipitated on the surface has a function of damage to pericellular membrane and cell wall, then thickens the cell wall, changes the appearance of the bacterium, ruptures the structure of the bacterium and even makes the karyon degraded. Eventually, it makes a lot of bacterium enchyma leak out and kills the bacterium.Salt wetting-drying test results show that stainless steel implanted by Cu ions or even treated with subsequent antibacterial process also maintain original good corrosion resistance.This work was support by The National Natural Science Foundation of China.