Preparation, Micro-Structure And Performance Of Antibacterial Film On Aluminum Surface

In recent years, the virus, avian flu pandemic, people pay more attention to the living environment. Antimicrobial materials can effectively inhibit bacteria and viruses, which have caught more and more eyes from researchers and the public, and its safety and reliability of the preparation method has become the focus of research and development. This paper mainly studies the preparation of antibacterial film derived from aluminum. At present, the traditional preparation process of the aluminum antibacterial material has two steps, namely, the first step is to prepare the oxide film through the direct current, and then the antibacterial ion is deposited by the alternating current. In this paper, the AC oxidation process is directly used for the preparation of antibacterial film, so it only contains one step. The method has the advantages of simple operation, high production efficiency, low energy consumption and low cost, so it is more suitable for industrial production.The pure aluminum sheet is the research object of this paper. Firstly, through a large number of experiments, the AC process parameter range was determined to prepare antibacterial functional aluminum film. And the better process was selected through the antibacterial test result on the preparation of 3mm thickness and high antibacterial aluminum. Moreover, by different test methods, this paper studied the influence of different parameters on the properties of the coating color, surface morphology, film thickness, film composition, antibacterial property, corrosion resistance and hardness. And through the analysis of film composition using XRD, XPS and EDS, the paper studied the forming mechanism of film.Research results show that:Considering antibacterial property of aluminum surface, production efficiency and production cost,4min oxidation time,8A/dm2 current density and 1.6g/1 AgNO3 concentration is better for the preparation of aluminum film whose thickness is 3mm with 99.9% antibacterial rate.In the range of parameters of the study, it is found that with the increase of the oxidation time, current density, AgNO3 concentration and the thickness of the aluminum sheet, the antibacterial rate of the films increases until 99.9%.As oxidation time is increased from 2min to 4min, the surface morphology of the film becomes more uniform and dense, with the film growing thicker and darker in color. Meanwhile the content of Ag in the film has a sharp rise, with the antibacterial rate, hardness and corrosion resistance improving. If oxidation time is increased to 6min, the film's density and uniformity decline, Besides, film thickness and content of Ag grow a little, leading to its surface color deepened. Moreover, the film antibacterial rate keeps 99.9%, with the hardness declined and corrosion resistance improved.As the current density is increased from 6A/dm2 to 8A/dm2, the film's color deepens and the surface becomes more uniform and dense. There is a substantial increase in the film thickness and the content of Ag, as well as the hardness and corrosion resistance of the film. Antibacterial rate increases to 99.9%. Current density continues to increase to 10A/dm2, leading to the enhancement of the surface color, as well as the film thickness and Ag content. The film's density and uniformity decline, as a result, the hardness and corrosion resistance of the film decreases. The film antibacterial rate remains 99.9%.The AgNO3 concentration in the electrolyte has no obvious influence on the surface morphology and film thickness, so the hardness and corrosion resistance of the aluminum sheet have no change prepared at different AgNO3 concentrations. But it makes the Ag content in the film have great changes. Besides, it also has a greater impact on the color and antibacterial rate of the film.With the increase of substrate thickness, the density and uniformity of the film become better. The thickness of the film and the content of Ag are increasing, too. Therefore, the color of the film is continuously deepened, with the antibacterial property, the corrosion resistance and the hardness increasing.The film formation process is divided into two steps. In alternating current positive period, the aluminum plate into membrane reaction, XRD results has proved the presence of Al2O3. In the negative period, Ag deposits, XPS showed deposition of silver element has both elemental and oxidation state. And the oxidation state of silver has a strong reduction potential, so it can be effectively sterilized.