Comparative Study on the Inhibition of Iron Corrosion in Aerated Stagnant 3.5 wt % Sodium Chloride Solutions by 5-Phenyl-1H-tetrazole and 3-Amino-1,2,4-triazole

Abstract

A comparative study on the inhibition of iron corrosion in 3.5 wt % NaCl solutions by 5-phenyl-1H-tetrazole (PHTA) and 3-amino-1,2,4-triazole (ATA) was investigated using a variety of electrochemical measurements. The potential-time curves revealed that PHTA and ATA shift the potential of iron toward the positive values. Electrochemical impedance spectroscopy measurements indicated that the presence of PHTA and ATA and the increase of their concentrations decrease the iron corrosion by increasing the solution and polarization resistances. This effect also decreases the corrosion current and corrosion rate for iron as confirmed by potentiodynamic polarization data. Potentiostatic current–time curves indicated that the presence of PHTA and ATA molecules decreases the absolute current and severity of pitting corrosion of iron in the test solutions. In situ Raman spectra for iron in chloride solution containing PHTA and ATA confirmed that the inhibition of iron corrosion is achieved by the adsorption of PHTA and ATA molecules onto its surface.