| The stainless steel is one of the most useful metal materials in human life,it is widely used in various fields because of its good corrosion resistance,mechanical properties and machinability.However,in some special fields,such as kitchen and bathroom products,biological medicine application,the surface of stainless steel is easily contaminated by dust and smudginess,which becomes a breeding ground of bacteria and threatens people's health.Therefore,research on stainless steel products with antibacterial properties has broad application prospects.As one of the surface modification methods,the anodizing of stainless steel has gradually become a hotspot.The micro-nano porous structure formed on the surface by anodizing has good potential,and can be used as a carrier for the deposition and attachment of functional substances,which provides a new idea for the preparation of antibacterial stainless steel.In this paper,we used 304 stainless steel as research object and systematically studied the effect of phosphoric acid content,electrolyte temperature,oxidation voltage and time on the formation of surface nanostructure in H3PO4-ethylene glycol electrolyte system.We preliminarily analyzed the formation mechanism of the nano porous structure on the surface of stainless steel,and then selected the best process parameters.We deposited Ag,Cu into the nanopores by electrochemical deposition to prepare Ag,Cu containing antibacterial films,and coated Ag-doped titanium dioxide sol on the surface of the nano porous structure to prepare Ag-doped titanium dioxide antibacterial films.The effects of relevant process parameters on the morphology,wear resistance,corrosion resistance,antibacterial property and hydrophobic property of film were studied.The research results are as follows:1.Uniform and ordered nano porous oxide film can be formed on the 304 stainless steel under the process parameters as follow:the volume ratio of phosphoric acid-ethylene glycol was 3:7,the electrolyte temperature was 0?,the oxidation voltage was 15V,and the oxidation time was 1h.The thickness of the nano porous oxide film was 2?3?m and the diameter of nanopores was about 100nm.2.During the deposition process,when the voltage was low or the time was short,the deposition layer was thin and the sediment was unevenly distributed in the nanopores;Contrarily,the deposition layer was corroded by the acidic electrolyte and fall off from stainless steel with the high voltage or long time.The results showed that a flat and uniform Ag-containing antibacterial film can be formed with the voltage of 5V for 2min,the sterilizing rate of E.coli can reach 99.9%;a flat and uniform Cu-containing antibacterial film can be formed with the voltage of 10V for 5min,the sterilizing rate of E.coli can reach 92.0%.3.The nano porous structure on the surface of stainless steel was conductive to improving the infiltration between the Ag-doped titanium dioxide sol and stainless steel.the Ag-doped titanium dioxide film was firmly combined with stainless steel after heat treatment.At the same time,the doping of Ag+increased the antibacterial effect of titanium dioxide,the sterilizing rate of Ag-doped titanium dioxide antibacterial film can reach 92.0%when the mass percentage of Ag/Ti O2 in the sol was 4%.4.Compared with ordinary stainless steel,the corrosion resistance and wear resistance of the antibacterial stainless steel prepared by electrochemical deposition and sol-gel spin coating had been significantly improved.The good hydrophobic property of the antibacterial stainless steel can reduce the stay of stains on the surface,not only had the effect of self-cleaning,but also reduced the growth and reproduction of bacteria on the surface. |
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