Gravity-driven corrosion effects in microbiologically influenced corrosion: Circumferential corrosion distribution of 90/ 10 Cu-Ni alloy by Desulfovibrio vulgaris

This work systematically examined the impact of gravity on Desulfovibrio vulgaris deposition, biofilm formation, and microbiologically influenced corrosion (MIC) behavior on 90/10 copper-nickel (Cu-Ni) at different clock positions (6 P, 9 P, and 12 P). Gravity exerted a significant influence on biofilm formation and the severity of MIC on 90/10 Cu-Ni alloy. The circumferential corrosion distribution on the inner surface of alloy pipeline exhibited substantial positional variation, with the most severe corrosion occurring at 6 P. Under static incubation conditions, the D. vulgaris sessile cell count at 6 P was 28 % higher than 12 P, and the weight loss at 6 P reached 8.6 ± 0.5 mg/cm², which was 1.3-fold and 1.7-fold greater than that at 9 P and 12 P, respectively. The thickness of D. vulgaris biofilm and MIC progression followed the trend: 6 P > 9 P > 12 P. Under dynamic incubation conditions, the differences in MIC across the positions diminished due to shear stress modulating the development of the D. vulgaris biofilm. Stirring mitigated gravitational effects, promoting a more uniform D. vulgaris biofilm distribution and MIC rate.