Inhibition of microbiologically influenced corrosion in 90/10 CuNi alloy by a novel antibacterial peptide

Microbiologically influenced corrosion (MIC) poses a serious threat to the structural integrity of CuNi alloys under marine service conditions. This study proposed a novel antibacterial peptide (Tcs) combined with Alkyl Dimethyl Benzyl Ammonium Chloride (ADBAC) to inhibit MIC in 90/10 CuNi alloy induced by Desulfovibrio ferrophilus IS5. Bacterial counts, environmental parameters analysis, surface morphological analyses, weight loss measurements, and electrochemical tests were conducted, through which the antibacterial and corrosion inhibition effects were demonstrated. The results showed that 180 ppb Peptide Tcs (180 Tcs) alone exerted almost no inhibitory effect on D. ferrophilus IS5, whereas a significant concentration-dependent enhancement was observed when Peptide Tcs was combined with 20 ppm ADBAC (20 ADBAC). Specifically, the 20 ppm ADBAC +180 ppb Peptide Tcs (20 ADBAC-180 Tcs) combination further reduced sessile bacterial counts by one order of magnitude compared to 20 ADBAC alone, while the weight loss rate and maximum pitting depth decreased by approximately 86 % and 61 %, respectively. These findings provide new insights into optimizing traditional biocide systems with small antimicrobial peptides and developing green, efficient strategies for controlling marine MIC.