Nonlinear dynamics of potassium iodide adsorption on the interface of carbon steel in acidic medium

• Published in: Materials and corrosion 2020-07, Vol.71 (7), p.1152-1159
• Main Authors: Garcia‐Ochoa, Esteban, Maldonado, Pablo, Corvo, Francisco
• Format: Article
• Language: English
• Subjects: Adsorption; carbon steel; Carbon steels; Charge transfer; Corrosion effects; Corrosion inhibitors; Electrochemical impedance spectroscopy; Electrochemical noise; Fractal geometry; Fractals; inhibitor; Metal surfaces; Nonlinear analysis; Nonlinear dynamics; Nonlinear phenomena; Potassium; potassium iodide; Potassium iodides; Surface chemistry
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.201911325

The development of inhibitors for hydrochloric acidic media is very common. Potassium iodide, in combination with some organic inhibitors, may transform a mediocre inhibitor into an excellent corrosion inhibitor based on a synergetic effect. There is a need to study what happens at the interface in the presence of this compound. The dynamics of the metal electrolyte interface when KI concentration increases has been characterized. The present study has been carried out based on electrochemical impedance spectroscopy and electrochemical noise analysis in the light of nonlinear phenomena by applying recurrence plots and fractal geometry. The fractal dimension of the current–time series shows a direct relationship with the fractal dimension of the surface of steel. The phenomenon of self‐organization has been observed on the metal surface. The nonlinear analysis carried out by means of recurrence plots showed that the iodide ions' inhibitory effect is not only simple adsorption but also a nonlinear phenomenon that auto‐organizes. The degree of complexity increases, consequently causing an interaction between the microcells and resulting in a lower charge‐transfer rate. Potassium iodide, in combination with some organic inhibitors, may transform a mediocre inhibitor into an excellent corrosion inhibitor based on a synergetic effect. The dynamics of the metal electrolyte interface when KI concentration increases has been characterized. The present study has been carried out based on electrochemical impedance spectroscopy and electrochemical noise analysis in the light of nonlinear phenomena by applying recurrence plots and fractal geometry.