Psidium Guajava Leaf Extract as Green Corrosion Inhibitor for Mild steel in Phosphoric Acid

摘要

The adsorption and corrosion inhibition property of the alcoholic Psidium guajava (guava) leaf extracton mild steel in 1M phosphoric acid medium was investigated by weight loss, potentiodynamicpolarization and electrochemical impedance spectroscopy techniques. The studies showed that theinhibition efficiency increases with inhibitor concentration upto 800 ppm and decreases slightly at1200 ppm. The adsorption obeys both the Langmuir and the Temkin adsorption isotherm equations.The kinetic and thermodynamic parameters were calculated and discussed. The adsorption was foundto follow a comprehensive type adsorption dominated by chemisorption. Potentiodynamic polarizationstudies showed that the inhibitor acted as a mixed-type inhibitor.