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

The corrosion and corrosion inhibition of Pb and Pb–In 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 efcient corrosion inhibitor for Pb and Pb–In alloys in HCl solution. The inhibition efciency (η %) for Pb and its investigated alloys increases with an increase in the concentration of PA and decreases with increasing temperature. The maximum inhibition efciency (≈80%) was obtained at 1×10−3 M of the PA inhibitor. Langmuir adsorption isotherm fts well the experimental data. SEM/EDX observations of the electrode surface confrmed the existence of an adsorbed flm. 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 Pb–0.5In alloy.