Fractal and multifractal analysis of electrochemical noise to corrosion evaluation in A36 steel and AISI 304 stainless steel exposed to MEA-CO2 aqueous solutions

•Capturing CO2 by MEA solutions is efficient but causes corrosion problems in operating equipment.•Corrosion is a complex process, making it difficult to monitor and diagnose.•Potential and current time-series contains relevant information about the corrosion evolution.•Fractal and multifractal analysis are shown as an inexpensive and easy qualitative tool for corrosion diagnosis. In this work, a proposal based on the fractal and multifractal analysis of electrochemical noise (EN) to corrosion evaluation in A36 steel and AISI 304 stainless steel, exposed in aqueous solutions of monoethanolamine (MEA) with carbon dioxide (CO2), is presented. Time-series of potential and current captured during the corrosion process of both steels exposed to different conditions of temperature and MEA concentration were analyzed using the rescaled range (R/S) method. The R/S analysis identified three characteristic regions that suggest that the time-series contain information associated with different physical phenomena in the corrosion process, that could be related to transport mechanisms and chemical reactions. The Hurst exponents calculated allow identifying correlations associated with the type and degree of corrosion, as well as information on the corrosion mechanisms of both steels evaluated. Hence, the Hurst exponent calculated from potential and current time-series could be used as an inexpensive and easily implemented tool for rapid diagnosis of the corrosive effects in the steel equipment used in the absorption processes of CO2 capture with amines.