Corrosion Inhibition of Aluminum and Copper in Hydrochloric Acid Solutions Using Extracts of Almond Leaves (Terminalia catappa) Leaves (TCE)

The corrosion inhibition efficiency of Almond leaves extract on copper and aluminum in 0.5M hydrochloric acid solution was studied using weight loss method, Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The results drawn from the different techniques are comparable and exhibit minimum discrepancy. Inhibition efficiency was found to increase with increase in concentration. However, temperature affected both metals differently. Inhibition efficiency increased with increase in temperature to maximum of 48.31% at 323K corrosion inhibition of copper and decreased as temperature increased and was maximum 92.23% at 303K The inhibition occurred via adsorption of the TCE molecules on the metallic surface according to Langmuir adsorption isotherm for copper and Flory Huggins isotherm for aluminum. Both kinetic and thermodynamics parameters were calculated and discussed. SEM analysis revealed that the addition of inhibitor slows down the corrosion processes for the two metals. The FTIR Spectroscopy identified the functional groups responsible for the adsorption of the molecules on the metals through the intensities and wave number of the dominant peak.