Corrosion Inhibition of Machilus Yunnanensis Leaves Extract for Steel in H2SO4 Solution

Machilus yunnanensis leaves extract (MYLE) is a kind of “green” inhibitor. The inhibition of MYLE on the corrosion of cold rolled steel (CRS) in 0.5 mol/L H2SO4 was studied by means of weight loss method, polarization curves and electrochemical impedance spectroscopy (EIS). The results show that the MYLE is a good inhibitor in sulfuric acid for CRS, and the adsorption of MYLE on the CRS surface obeys modified Langmuir adsorption isotherm equation. Polarization curves show that MYLE is a mixed-type inhibitor. EIS exhibited one capacitive loop at high frequencies and followed by a small inductive loop at low frequencies, and the charge transfer resistance increased with the increase of the inhibitor concentration.