Microbiologically influenced corrosion of CoCrFeMnNi high entropy alloy by sulfate-reducing bacterium Desulfovibrio vulgaris.

Sulfate-reducing bacterium Desulfovibrio vulgaris promoted the microbiologically influenced corrosion (MIC) of CoCrFeMnNi high entropy alloy (HEA) and led to pitting corrosion. D. vulgaris caused the formation of metal sulfides and thinning of passive film. The corrosion resistance decreased, and pit depths increased when the carbon source reduced to 40%. The relative expression of hydrogenase genes hydA and hydB in the biofilms under 40% carbon source significantly increased, indicating that the indirect electron transfer mediated by 2H+/H 2 might play an important role in promoting the HEA MIC by D. vulgaris under starvation. • Desulfovibrio vulgaris promotes CoCrFeMnNi HEA MIC and causes pitting corrosion. • The presence of D. vulgaris causes the thinning of HEA passive film. • In the starved 40% carbon source level, D. vulgaris leads to more aggressive HEA MIC. • Two hydrogenase genes (hydA and hydB) upregulate in the starvation condition. • The indirect electron transfer mediated by 2H+/H 2 may play an important role in starvation. [ABSTRACT FROM AUTHOR]