Corrosion inhibition efficiency and adsorption characteristics of some Schiff bases at mild steel/hydrochloric acid interface

• Among the studied inhibitors, BDTC exhibited 91% inhibition efficiency.
• Polarization curves indicated that all the Schiff bases act as mixed-type inhibitors.
• Adsorption of all the inhibitors on mild steel surface obeyed Langmuir's isotherm.
• Disappearance of CHN and CONH peaks in IR spectra indicated strong adsorption.
• Smooth surface of inhibited surface in SEM images showed high protection efficiency.
• The antioxidant activity of the Schiff bases was correlated with IE %.

The corrosion inhibition efficiency of newly synthesized Schiff bases was investigated for mild steel (MS) corrosion in 0.5 M HCl medium using mass loss and electrochemical techniques. The potentiodynamic polarization results indicated that all the studied inhibitors act as mixed type. The adsorption process on MS surface obeyed Langmuir isotherm. The associated activation parameters and thermodynamic data of adsorption were evaluated and discussed. The adsorbed film formed on the metal surface was characterized by SEM and IR-spectroscopy. Further, antioxidant activity of the Schiff bases was determined and correlated the results obtained with inhibition efficiency.