Enhanced resistance of 2205 Cu-bearing duplex stainless steel towards microbiologically influenced corrosion by marine aerobic Pseudomonas aeruginosa biofilms

An antibacterial 2205-Cu duplex stainless steel (DSS) was shown to inhibit the formation and growth of corrosive marine biofilms by direct contact with copper-rich phases and the release of Cu2+ ions from the 2205-Cu DSS surface. In this work, the microbiologically influenced corrosion (MIC) resistance of 2205-Cu DSS in the presence of the corrosive marine bacterium Pseudomonas aeruginosa was investigated. The addition of copper improved the mechanical properties such as the yield strength, the tensile strength and the hardness of 2205 DSS. Electrochemical test results from linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and critical pitting temperature (CPT) measurements showed that 2205-Cu DSS possessed a larger polarization resistance (Rp), charge transfer resistance (Rct) and CPT values, indicating the excellent MIC resistance of 2205-Cu DSS against the corrosive P. aeruginosa biofilm. The live/dead staining results and the SEM images of biofilm confirmed the strong antibacterial ability of 2205-Cu DSS. The largest pit depth of 2205-Cu DSS was considerably smaller than that of 2205 DSS after 14 d in the presence of P. aeruginosa (2.2 μm vs 12.5 μm). 2205-Cu DSS possessed a superior MIC resistance to regular 2205 DSS in the presence of aerobic P. aeruginosa.