Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (10): 2221-2231.doi: 10.3866/PKU.WHXB201307301

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Inhibition Effect of Pyrimidine Derivatives on the Corrosion of Steel in Hydrochloric Acid Solution

LI Xiang-Hong1,2, XIE Xiao-Guang1   

  1. 1 School of Chemical Science and Technology, Yunnan University, Kunming 650091, P. R. China;
    2 Faculty of Science, Southwest Forestry University, Kunming 650224, P. R. China
  • Received:2013-05-22 Revised:2013-07-25 Published:2013-09-26
  • Contact: LI Xiang-Hong E-mail:xianghong-li@163.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51361027).

Abstract:

The inhibition effect of two pyrimidine derivatives, 2- hydroxypyrimidine (HP) and 2- mercaptopyrimidine (MP), on the corrosion of cold rolled steel (CRS) in 1.0-5.0 mol·L-1 HCl is investigated by mass loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and quantum chemical calculations. The results show that HP and MP are both good inhibitors of corrosion of CRS in 1.0 mol·L-1 HCl solution. The adsorption of these inhibitors onto the CRS surface obeys the Langmuir adsorption isotherm. Inhibition efficiency increases with inhibitor concentration, and decreases with hydrochloric acid concentration. The thermodynamic parameters of adsorption (adsorption equilibrium constant (K) and adsorption free energy (ΔG0)) and kinetic parameters of corrosion (apparent activation energy (Ea), pre-exponential factor (A), corrosion rate constant (k), and kinetic reaction constant (B)) are also calculated. Based on these parameters, the mechanism of inhibition is discussed. Potentiodynamic polarization curves show that HP and MP act as mixed-type inhibitors. EIS exhibit one capacitive loop, and the charge transfer resistance increases with inhibitor concentration. The results of quantum chemical calculations indicate that MP exhibits higher adsorptive ability than HP, which is in good agreement with the experimental data.

Key words: Corrosion inhibitor, 2-Hydroxypyrimidine, 2-Mercaptopyrimidine, Steel, Hydrochloric acid, Adsorption, Quantumchemical calculation

MSC2000: 

  • O646