Because marine engineering equipment and structural components are used in harsh corrosive environments, their underwater structures have long been affected by seawater erosion and microbes, so they have higher requirements for corrosion resistance. For stainless steel for marine engineering equipment (purchasing supply of products), chloride ion corrosion and microbial corrosion in seawater have always been recognized as challenges in the world. The major developed countries in the world have set up national strategic projects to support research and development in this field. But they have not solved the problem well. The microbial corrosion and biofouling problems of marine engineering materials have caused nearly one trillion yuan of economic losses to the country and 30% of the energy waste of Shanghai's medium-sized navigation bodies, which has become one of the technical bottlenecks that seriously restrict the development of major marine engineering technologies and equipment. The material failure caused by it is a serious impact on the reliability and longevity of offshore engineering equipment. Therefore, the microbial corrosion failure mechanism and protection technology of marine engineering materials have become a major problem to be solved in the field of marine engineering in China.
Studies have confirmed that the main cause of microbial corrosion of marine metal structures is the formation of bacterial biofilms on metal surfaces. If it can effectively inhibit and kill the bacterial biofilm adhered to the surface of the metal material, it can effectively alleviate or inhibit the occurrence of microbial corrosion. Therefore, it is an innovative new idea to utilize the antibacterial properties of antibacterial stainless steel and its inhibition on the formation of bacterial biofilm to improve the anti-microbial corrosion resistance of stainless steel. The Yangke research team of the Institute of Metals has used the strong bactericidal properties of copper ions to develop a variety of copper-containing antibacterial stainless steels such as austenite, ferrite and martensite as early as the beginning of this century. Common bacteria such as Escherichia coli, Staphylococcus aureus, Candida albicans, Aeromonas and other bacteria in life have obvious killing effects.
In response to the bacterial biofilm formed by stainless steel in the marine environment, under the guidance of researcher Yang Ke, Dr. Xu Dake and Dr. Yang Chunguang of the research team have recently successfully developed an antibacterial duplex stainless steel with microbial resistance. 2205-Cu). The results showed that the 2205-Cu stainless steel was co-cultured with Pseudomonas aeruginosa for 22 days under the conditions of 2216E medium, and the sterilization rate reached 96.9%. After 14 days of co-cultivation, the deepest pitting depth caused by microbial corrosion on the surface of ordinary 2205 duplex stainless steel was 9.50 mm, while the deepest pitting depth caused by microbial corrosion on the surface of 2205-Cu antibacterial duplex stainless steel was only 1.44 mm. Corrosion current density results obtained by polarization curves also show that 2205-Cu antibacterial duplex stainless steel has strong resistance to microbial corrosion, and corrosion current density after co-culture with P. aeruginosa for 14 days under 2216E medium. It is only 0.04μA cm-2, while the ordinary 2205 duplex stainless steel has a corrosion current density of 0.20μA cm-2.
2205 Duplex stainless steel is the most widely used duplex stainless steel in the marine environment. The recent reports on the corrosion of 2205 duplex stainless steel caused by marine bacterial corrosion have attracted widespread attention.
The advent of 2205-Cu, an antibacterial duplex stainless steel with strong resistance to microbial corrosion, fills the gap in the field of marine antibacterial engineering materials. The research results have important academic significance and practical application value. The results of the study have recently been published in Biofouling Biofouling (2015, 31, 481-492) and have been filed for national invention patents. The research was funded by the National Key Basic Research Development Program (973 Program), the National Material Environmental Corrosion Platform, and the Institute of Metal Research of the Chinese Academy of Sciences.
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