Microbiologically influenced corrosion of TiZrNb medium-entropy alloys by Desulfovibrio desulfuricans

Highlights: • The MIC of TiZrNb medium-entropy alloys (MEAs) was studied for the first time. • D. desulfuricans can induce the pitting of TiZrNb MEA underneath the biofilm. • Corrosion current density of MEA with D. desulfuricans was 12 times larger than that without D. desulfuricans. • D. desulfuricans prefer to acquire the electrons from Ti in MEA via an EET mechanism. -- Abstract: The microbiologically influenced corrosion of TiZrNb medium-entropy alloys (MEAs) by Desulfovibrio desulfuricans was investigated. Pitting corrosion was found on coupon surface after 14-day immersion in the inoculated medium. Electrochemical tests demonstrated that the corrosion of coupon was enhanced by the D. desulfuricans. The corrosion current density (i_corr) in the inoculated medium is approximately 12 times as much as that in the abiotic medium. In the presence of biofilms, the selective dissolution of Ti occurred, particularly when the organic nutrients were insufficient. Ti⁰ can be used as an electron donor by microbes in their energy metabolism once other donors are not readily available.