Study Of The Corrosion Behaviour Of 2205 Duplex Stainless Steel In The Environment Containing Pseudomona Saeruginosa

The sea is the basis of economic and military,exploiting and using the ocean resources become the inevitable trend of development.Material corrosion and the marine environment protection become the key issues.2205 duplex stainless steel has the advantages of ferritic and austenitic stainless steel,high strength,toughness,and good corrosion resistance,and it is widely used in offshore drilling platforms,port facilities,etc,but at the same time it still faces the threat of corrosion caused by microorganisms.Pseudomonas aeruginosa is a kind of very important corrosion bacteria in the ocean,it can cause the corrosion of carbon steel and stainless steel,it has caused huge losses on economy and environment.However the corrosion mechanism of pseudomonas aeruginosa is not clear,whether pseudomonas aeruginosa can ead to pitting corrosion of duplex stainless steel is rarely reported.Therefore,studying the corrosion behavior of 2205 duplex stainless steel in the medium containing pseudomonas aeruginosa is representative and practical significance.Electrochemical testing techniques are commonly used in the study of microbial corrosion,such as electrochemical impedance spectroscopy and potentiodynamic polarization curve test,etc.,but the external disturbances in the process of the test may have affect on the biological activity of microorganism.Therefore,this work has studied the applicability of inear polarization,electrochemical impedance spectroscopy and electrochemical noise echnologies in the study of pseudomonas aeruginosa influenced corrosion.Studies have shown that electrochemical impedance spectroscopy and linear polarization test need to exert different degrees of polarization in the test process,and the polarization will affect the activity of pseudomonas aeruginosa.Electrochemical noise doesn't need external disturbances in the est process,it can not influence the activity of microorganism and has a good applicability in he study of pseudomonas aeruginosa influenced corrosion.This work used a combination of electrochemical noise test and Hilbert-Huang analysis o study the corrosion behavior of 2205 duplex stainless steel in the medium of pseudomonas aeruginosa.Electrochemical noise technologies can detect corrosion rate.At the same time,he Hilbert-Huang analysis is a very novel analysis method,it can go ahead with the me-frequency analysis of electrochemical noise,the short transient change can be separated from background signal.Studies have shown that pseudomonas aeruginosa can catalytic oxidation Cr2O3 generate CrO3,the passivation membrane under the bottom of the biofilm was dissolved.Therefore,the biofilm formed by pseudomonas aeruginosa can cause rapid pitting nucleation.In the presence of pseudomonas aeruginosa,the pitting sensitivity of 2205 duplex stainless steel and the probability of the formation of the steady-state pitting are improved,pseudomonas aeruginosa may be the key factor of pitting growth.For the corrosion behavior of 2205 duplex stainless steel in the medium of pseudomonas aeruginosa,we had added a certain content of copper in 2205 duplex stainless steel and obtained 2205-Cu duplex stainless steel,and then studied the influence of Cu element on the corrosion behavior of 2205 duplex stainless steel in pseudomona saeruginosa medium.Studies have shown that the addition of Cu increased the pitting corrosion resistance of 2205 duplex stainless steel in the medium of pseudomonas aeruginosa.Cu has very strong antibacterial properties,it can restrain the adsorption of the pseudomonas aeruginosa and formation of the biofilm.The addition of Cu element made the pitting sensitivity and the probability of pitting corrosion of 2205 duplex stainless steel in pseudomonas aeruginosa were significantly reduced.