Research On Preparation Of Antibacterial Functional Materials By Implanting Ag Ions Into Stainless Steel

With the development of society and improvement of people's life, human's consciousness of hygiene safety and cleanliness enhanced, the research and application of antibacterial materials have developed broadly and quickly. In the 1990's, some developed countries manufactured stainless steel with antibacterial activity, which have been used in many fields. The present process to prepare the antibacterial stainless steel is that copper or silver is added into stainless steel during smelting at first, and then stainless steel should be token hot-treatment to obtain antibacterial activity. In this paper, Metal Vapor Arc (MEVVA) sources have been used for silver ion implantation to prepare the antibacterial martensitic stainless steel, and antibacterial mechanism of silver has been also discussed.Silver ion implantation has been carried out with the implantation energy of 100keV and ion doses ranging from 0.1×1017ions/cm2 to 8×1017ions/cm2. The antibacterial and anticorrosive property of stainless steel was investigated respectively by the agar-plate method and electrochemical test. The effects of implantation dose on antibacterial and anticorrosive property have been discussed. Auger electronic spectrum (AES) was employed to analyze the distribution of element in materials such as Ag, Fe, Cr and so on.The result of antibacterial test showed that un-implanted stainless steel had no antibacterial activity. The rate of cell reduction against Escherichia coli and Staphylococcus aureus increased with the increasing implantation dose of silver ion with the implantation energy of 100keV. The antibacterial property against Escherichia coli excelled to Staphylococcus aureus obviously in the same condition. Stainless steel which was implanted with a dose of 8×1017ions/cm2 performed excellent antibacterial property against Escherichia coli and Staphylococcus aureus, the rate of cell reduction was 100% and 82% respectively.The results of the anodic polarization curve test showed that the anticorrosive property of stainless steel implanted by appropriate dose was better than originality stainless steel, but the anticorrosive property of stainless steel implanted by exceeding saturation dose was less than originality stainless steel with energies of 100keV.The results of AES indicated the peak value of silver's concentration did not increase after ion implantation dose exceed to saturation value, however, the depth of implantation layer with a high silver concentration became larger obviously because of effect of enhancement diffusion, which it seems to be helpful of the improvement of antibacterial property. The surface concentration of chromium declined obviously because of priority sputter, which resluted in a little reduction of the anticorrosive property of stainless steel.