Corrosion inhibition and adsorption behavior of phytic acid on Pb and PbâIn alloy surfaces in acidic chloride solution

Abstract

The corrosion and corrosion inhibition of Pb and PbâIn alloys in HCl solution, were investigated. The study was performed in the absence and presence of the phytic acid (PA) inhibitor using potentiodynamic polarization and electrochemical impedance spectroscopy measurements, and complementary by scanning electron microscope (SEM) and X-ray spectroscopy analysis (EDX) investigations. The obtained outcomes showed that the PA is efficient corrosion inhibitor for Pb and PbâIn alloys in HCl solution. The inhibition efficiency (η %) for Pb and its investigated alloys increases with an increase in the concentration of PA and decreases with increasing temperature. The maximum inhibition efficiency (ââ80%) was obtained at 1âÃâ10^â3 M of the PA inhibitor. Langmuir adsorption isotherm fits well the experimental data. SEM/EDX observations of the electrode surface confirmed the existence of an adsorbed film. One can conclude that the increase in activation energy with increasing additive concentration, in addition to the decrease in η % in the presence of inhibitor with temperature, is suggestive of physical adsorption of the inhibitor molecules on the surface of Pb and Pbâ0.5In alloy.