Effects of Cinnamaldehyde as an Eco-Friendly Corrosion Inhibitor on Mild Steel in Aerated NaCl Solutions

This article investigates the impact of cinnamaldehyde as an eco-friendly inhibitor in mitigating corrosion detriment on mild steel in aerated NaCl (3% w/w) using weight loss and potentiodynamic polarization methods.The results indicate moderate inhibition efficiency of cinnamaldehyde reaching around 70% at an optimum level of 0.5 g/L or 500 ppm by establishing an adsorption film on metal surface. Adsorption of the cinnamaldehyde seemed to adhere to the Langmuir isotherm. The corrosion rate decreased with cinnamaldehyde dose up to the optimum level while increased slowly with the medium temperature. The activation energy (E_a) achieved with cinnamaldehyde was found to be lower than that of without cinnamaldehyde. The polarization curves revealed that the inhibitor performs as a mixed-type inhibitor since it diminishes both anodic and cathodic current densities. The calculated inhibition efficiencies using both corrosion monitoring techniques were found to be in good agreement. Additionally, the mild steel surfaces (inhibited and uninhibited) were examined by using SEM–EDX analysis.