Electrochemical Investigation of the Anti-corrosive Effect of Spondias mombin Leaves Extract on the Corrosion of Aluminium Alloy (AA2024) and Mild Steel in 0.5 M NaCl

Abstract

The inhibiting effect of Spondias mombin (SM) leaves extract on the corrosion of AA2024 and mild steel in 0.5 M NaCl environment was investigated using electrochemical techniques. Tafel plots obtained from the potentiodynamic polarization (PDP) experiments indicate that for both metals, the curves shifted toward more negative values of the corrosion current density (Icorr) as the inhibitor concentration increased. More so, for all concentrations of the inhibitor, the values of maximum displacement shift in corrosion potential (Ecorr) were found to be less than 85 mV. This shows that SM behaves like a mixed-type corrosion inhibitor. The electrochemical impedance spectroscopy (EIS) study shows that for both metals, the charge transfer resistance (Rct) values increased with an increase in concentration of the inhibitor. The increase in values of Rct can be attributed to the formation of protective film at the metal-solution interface. The Nyquist plots show semi circles whose diameter increased as the inhibitor concentration is increased and this is suggestive of retardation in corrosion process. The inhibition efficiency values obtained in the EIS experiment were found to be in close conformity with those of the PDP experiment.

Novel high-performance and cost-effective green inhibitor based on fundamental theoretical evaluations combined with electrochemical/surface examinations of Arachis hypogaea shell extract for pipeline steel corrosion in 1 M H2SO4 solution

“…From the polarization curves, the major shift of cathodic and anodic branches to lower current densities values is obvious signifying that the AHS reduced the cathodic and anodic corrosion reactions via mixed inhibition mechanisms. The displacement in the Ecorr towards more negative value is lower than ±85 mV as shown in table 1, signifying that the AHS behaves as mixed inhibitor [31].…”