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

Abstract

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 efficient corrosion inhibitor for Pb and Pb-In 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 (≈ 80%) was obtained at 1 × 10 −3 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 Pb-0.5In alloy.

The inhibitive action of 2-mercaptobenzothiazole on the porosity of corrosion film formed on aluminum and aluminum–titanium alloys in hydrochloric acid solution

“…In the case of Al, AT-2 (except for 2-MBT shifts to a positive value in the presence of 0.001 mM), and AT-4, the change in the values of potential E corr to negative proves that the inhibitor is a mixed type, and mainly cathodic 30 ; with 2-MBT concentrations, this tendency is attributed to variations in the potential of the hydrogen evolution process toward more negative potentials. This shift may indicate that active cathodic sites are more blocked than anodic ones 31 . It is also evident from AT-1 and AT-3 alloy that the addition of inhibitor shifted corrosion potential E corr in an anodic direction, indicating that the inhibitor's adsorption was more successful at anodic than cathodic sites 32 .…”

“…This was supported by the observed shift in the E corr value obtained in the solution, which was less than 85 mV after adding 2-MBT compared to the bare HCl solution 39 . The Al-Ti phase on the alloy surface may be responsible for this opposing impact observed at different inhibitor concentrations in contrast to the pure Al 31 .…”

Exploration of synthesized quaternary ammonium ionic liquids as unharmful anti-corrosives for aluminium utilizing hydrochloric acid medium

“…The data of ΔG ads ranging up to -20 kJ mol À1 are generally associated with some electrostatic interaction taking place around the charged metal surface and BOPAMS and BOBAMS (physical adsorption) while the data around -40 kJ mol À1 and beyond are associated with the exchange of electrons between Al and BOPAMS and BOBAMS resulting in the formation of a strong chemical bond (chemical adsorption) (El-Lateef et al, 2019;Lgaz et al, 2016). In this work, the ΔG ads data for BOBAMS and BOPAMS were all above -20 kJ mol À1 yet slightly below -40 kJ mol À1 , signifying mixed-type binding process on Al surface, with a dominating chemisorption mechanism as the values are nearing the -40 kJ mol À1 value.…”

Inhibition Mechanism of Some Vinylalkylimidazolium-Based Polymeric Ionic Liquids against Acid Corrosion of API 5L X60 Steel: Electrochemical and Surface Studies

“…The behavior of f in the absence and presence of the PILs was as follows: at low f values (from 10 –1 to 10 1 Hz), it is observed that | Z | presented an approximate increase from 20 to 200 Ω cm 2 with respect to the blank; this fact suggests the occurrence of charge transfer, mass transfer, or surface relaxation processes associated with the adsorption of the CIs . In the region of intermediate f (from 10 1 to 10 3 Hz), a significant | Z | linear decay in the presence of PILs with respect to the blank and the formation of an ϕ max of 70° at high C INH were observed, which confirmed that the film formed on the surface is related to the charge transfer resistance and capacitance of the electric double layer. , Finally, in the high f region (from 10 3 to 10 5 Hz), constant | Z | values in the presence and absence of CIs are observed, which can be related to the solution resistance. It is worth mentioning that in this region the formation of a time constant also took place …”

“…44 In the region of intermediate f (from 10 1 to 10 3 Hz), a significant |Z| linear decay in the presence of PILs with respect to the blank and the formation of an ϕ max of 70°at high C INH were observed, which confirmed that the film formed on the surface is related to the charge transfer resistance and capacitance of the electric double layer. 45,46 Finally, in the high f region (from 10 3 to 10 5 Hz), constant |Z| values in the presence and absence of CIs are observed, which can be related to the solution resistance. It is worth mentioning that in this region the formation of a time constant also took place.…”