Electrochemical and Theoretical Studies on Amino Phosphonates as Efficient Corrosion Inhibitor for N80 Steel in Hydrochloric Acid Solution

摘要

Amino phosphonate compounds, namely, dimethyl-(4-methoxyphenyl) (phenylamino) methylphosphonate (DMMP) and dimethyl phenyl (phenylamino)methylphosphonate (DPMP) weresynthesized and studied as inhibitors for N80 steel corrosion in 15% HCl solution using thepotentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques.Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorptionof inhibitors on the N80 steel surface obey Langmuir adsorption isotherm. Scanning electronmicroscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and atomic force microscopy(AFM) were performed for surface study of uninhibited and inhibited N80 steel samples. Densityfunctional theory (DFT) was employed for theoretical calculations.