Effect of Cu addition to AISI 8630 steel on the resistance to microbial corrosion

Low-alloy, high-strength structural steel AISI 8630 is exposed to severe microbiologically influenced corrosion (MIC) in its application environment. To address this issue, we independently designed and developed an AISI 8630 steel containing 0.4 wt% Cu (Cu-AISI 8630) to exploit the Cu antimicrobial effect. The corrosion behavior of two steels in the presence of marine Pseudomonas aeruginosa biofilm was explored by analyzing weight loss, electrochemical tests, SEM images, corrosion pit dimensions, and corrosion products. The electrochemical test results showed an increase in Rp and a significant positive shift in Ecorr for Cu-AISI 8630 steel compared to AISI 8630 steel during the immersion cycles. A comparison of the pit morphology of AISI 8630 steel and Cu-AISI 8630 steel after 14 days showed that the maximum MIC pit depth was significantly reduced in the latter compared to the former (3.65 mu m vs 9.47 mu m). The XPS results showed that protective Cu2O and CuO layers were formed on the surface of Cu-AISI 8630 steel. The experimental results show that Cu improves the MIC resistance of Pseu-domonas aeruginosa biofilms significantly.