Inhibition effect of two mercaptopyrimidine derivatives on cold rolled steel in HCl solution

The inhibition effect of two mercaptopyrimidine derivatives of 4-amino-6-hydroxy-2-mercaptopyrimidine (AHMP) and 4,6-dihydroxy-2-mercaptopyrimidine (DHMP) on cold rolled steel (CRS) in HCl solution was studied by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), quantum chemical calculation and molecular dynamics (MD) simulations methods. The results show that both mercaptopyrimidine derivatives act as good inhibitors, and inhibition efficiency follows the order: AHMP > DHMP. The adsorption of either inhibitor on steel surface obeys Langmuir adsorption isotherm. Two mercaptopyrimidine derivatives are mixedtype inhibitors. The inhibitor molecules adsorb on the Fe (001) surface in the nearly flat manner. (C) 2014 Elsevier Ltd. All rights reserved.