Leucas Aspera leaves extract as a copper corrosion inhibitor in 0.5M H2 SO4 medium

The corrosion inhibitive action of leaves extracts of Leucas Aspera on copper corrosion in 0.5M H 2 SO 4 solution was studied using the weight-loss method, Potentiodynamic polarization, EIS measurements, SEM-EDXS and FT-IR spectroscopic techniques. The results obtained indicate that the extracts functioned as good inhibitors in 0.5M H 2 SO 4 solution. The inhibition efficiency was found to increase with extract concentration. Potentiodynamic polarization curves indicated that the plant extracts behave as mixed-type inhibitors. The thermodynamic parameters showed that the adsorption of the extracts on copper is physical, spontaneous, and favoured at low temperatures. The data for the adsorption of extract fit well with Langmuir adsorption isotherm. FTIR results showed that the inhibition mechanism was by the absorption process, through the functional groups present in the extract. The SEM images of the corrosion product confirmed the protection offered by the extract on the surface of the metal immersed in the 0.5M H 2 SO 4 medium.