The Anti corrosion behavior of the crude aqueous extract of Origanum Majorana on the mild Steel in acidic medium

The inhibition effect of Origanum majorana OM on the corrosion of mild steel in 1.0 M hydrochloric acid solution has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The corrosion inhibition efficiency increases by increasing the Origanum majorana concentration. The results from this corrosion test clearly reveal that the aqueous extract of Origanum majorana is a mixed type corrosion inhibitor with the highest inhibition at 1.0 g/L. The Nyquist plots showed that when OM concentration increase, charge-transfer resistance increased and double-layer capacitance decreased, involving increased inhibition efficiency. The adsorption of this OM on the mild steel surface obeys the Langmuir adsorption isotherm.