KI effects on corrosion inhibition for 1018 steel in acid media using Medicago sativa

• Published in: Frontiers in chemistry Vol. 10; p. 1032522
• Main Authors: Rodríguez-Torres, A, Valladares-Cisneros, M G, Saldaña Heredia, A, González-Rodríguez, J G
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 10-11-2022
• Subjects: Chemistry; corrosion inhibition; efficiency; electrochemical techniques; M. sativa; M. sativa; efficiency; corrosion inhibition; electrochemical techniques; KI
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2022.1032522

extract is a safe and eco-friendly corrosion inhibitor of 1018 steel in acid media. The inhibitor reached a maximum efficiency of 85% by using 500 ppm. In this work, we study the use of KI as an add-on to increase the inhibition efficiency of
, as well as making the natural inhibitor competitive with the commercial ones. We evaluated the effect of halide ions through the variation of different concentrations of KI and its synergy with the extract of
as a corrosion inhibitor of carbon steel in 0.5 M sulfuric acid and at different temperatures. The results were obtained through electrochemical techniques such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) curves, and weight loss gravimetric technique. It was found that halide ions increase the inhibition efficiency of
from 85 to 95% when 5 mM concentration of KI was used. The efficiency of the inhibition increases proportionally with the immersion time but reduces when the temperature increases. The addition of iodide ions (I-) revealed that it exerts a synergistic effect on the inhibition of corrosion with the extract of
. However, when studying the metal surface using a scanning electron microscope, pitting corrosion was found.