Corrosion Inhibition of Aluminium Alloy in Alkaline Media by Neolamarkia Cadamba Bark Extract as a Green Inhibitor

Abstract

The aqueous extract of Neolamarkia Cadamba (NC) bark was investigated as corrosion inhibitor for aluminium alloy (AA) in 1 M NaOH solution. The techniques employed for corrosion inhibition are weight loss, polarization resistance, Tafel polarization and electrochemical impedance spectroscopy (EIS). The inhibition efficiency increases with increasing the concentration and shows maximum inhibition efficiency (87 %) at optimum concentration (0.6 g/L). Polarization study revealed that it is a mixed type inhibitor. The existence of protective film on the surface of AA was confirmed by the scanning electron microscope (SEM).