Corrosion inhibition of steel in simulated seawater by Mikania micrantha extracts

The investigation of plant-based corrosion inhibitors in seawater has become a crucial topic for enhancing corrosion protection and promoting sustainable development, given the increasing severity of marine environmental pollution. The inhibition efficacy and adsorption mechanisms of Mikania micrantha extract (MME) were evaluated through weight loss methods, electrochemical tests, surface analysis, and theoretical simulations. The results showed that the maximum inhibition efficiency reached 98.9% at 1000 mg L -1 MME after 30 days of immersion. Electrochemistry test showed that MME functions as cathode-inhibiting inhibitor, with its electrochemical mechanism driven by the geometric coverage effect. The polarization resistance increased by approximately 30 times at an MME concentration of 1000 mg L -1 . This further confirms that MME can significantly inhibit corrosion reactions. MME can form a uniform adsorption film, which serves as an effective barrier, preventing corrosive particles from coming into contact with steel substrate, thereby exerting a potent inhibition effect. The -C-C=O functional group within MME has been identified as the key structural component responsible for its inhibition performance. This research opens up new avenues for the development of eco-friendly inhibitors, offering significant potential for practical applications in various industries. • Mikania micrantha extracts (MME) were prepared via a simple reflux extraction method. • Maximum inhibition efficiency of 98.9% achieved with 1000 mg L -1 MME after 30 days. • MME inhibits corrosion through a cathode-inhibiting mechanism via geometric coverage. • The -C-C=O group in MME is the key structural element for corrosion protection. • MME offers an environmentally friendly, sustainable solution for marine corrosion.