Green inhibition of microbiologically influenced corrosion on 316L stainless steel by Artemisia annua extract

316L stainless steel is widely used in marine and biomedical applications.However, its protective Cr-rich passive film can be destabilized by microbiologically influenced corrosion (MIC). Here, a multidisciplinary approach combining electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), optical profilometry, ATR-FTIR, X-ray photoelectron spectroscopy (XPS), and ICP-OES was used to investigate corrosion behavior and passive film chemistry of 316L stainless steel (SS) exposed to Pseudomonas aeruginosa in artificial seawater, and to evaluate the inhibitory effect of an aqueous Artemisia annua extract (AAE). Exposure to P. aeruginosa , resulted in a marked decrease in film resistance, increased corrosion current density, enhanced Fe dissolution, and pronounced surface pitting. Although biotic exposure increased the apparent oxide thickness, XPS analysis revealed the formation of a chemically heterogeneous and less protective surface layer. In contrast, the addition of AAE significantly mitigated these effects by stabilizing a Cr-enriched passive film, increasing charge-transfer resistance, reducing j corr , and suppressing localized attack. ATR-FTIR confirmed adsorption of phenolic acids from AAE, while XPS depth profiling revealed stabilization and thickening of the passive layer. The inhibition efficiency of AAE, evaluated by PP, EIS, and ICP-OES, ranged from 65% to 83%, demonstrating consistent protective behavior across all methods. These results indicate that A. annua extract acts as a plant-derived corrosion inhibitor that preserves the functional stability of the Cr-rich passive film under MIC conditions, offering a promising strategy for corrosion mitigation in marine environments. • Pseudomonas aeruginosa disrupts passivity of 316L in artificial seawater • Artemisia annua extract reduces Fe dissolution by 83% • Multimodal evidence from EIS, PP, ICP-OES, XPS and FTIR • Phenolic adsorption stabilizes Cr-rich passive film • Green inhibitor mitigates microbiologically influenced corrosion