Title : Multiscale characterization of microbiologically influenced corrosion on copper-nickel alloy exposed to natural seawater
Abstract:
Copper and its alloys are extensively used in marine and offshore structures such as heat exchangers and piping systems due to their excellent durability and corrosion resistance. However, they were reported to be susceptible to microbiologically influenced corrosion (MIC). Despite extensive research on MIC, the principle and mechanism that leads to increased corrosion are not completely understood. Therefore, a multi-technique approach involving electrochemical and surface characterization of Cu90/Ni10 alloy together with the identification of initial microflora and functional genes for biofilm formation and Cu tolerance could provide novel insights regarding MIC mechanisms of this antimicrobial Cu based alloys. This study aimed to analyze the influence of MIC on CuNi (90/10) and Titanium (control) metals exposed to natural seawaters (collected from Corpus Christi Port, TX) under stagnant laboratory conditions lasting 16 weeks. This analysis employed a multiscale characterization approach, encompassing traditional microbiological culturing, molecular analyses, electrochemical and surface characterizations. Metal coupons were gathered at specified intervals for subsequent analysis. Electrochemical assessment included monitoring of open circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy. Surface characterization of biofilm, corrosion products, and pitting corrosion analysis were performed using scanning electron microscopy, Raman spectroscopy, and optical profilometer. Traditional microbiological analysis included culturing and identification of Cu-resistant bacterial and fungal strains of biofilms. Molecular analysis was performed for quantification of functional genes responsible for Cu tolerance and biofilm formation using digital droplet-PCR. This presentation will highlight the key findings of the study and also discusses additional approaches to solve MIC-related challenges.
