Pitting corrosion and effect ofEuphorbia echinusextract on the corrosion behavior of AISI 321 stainless steel in chlorinated acid

Abstract

Stainless steel (SS) is a very corrosion-resistant alloy used in different industrial plants because of its chemical and mechanical properties. However, the high chloride concentration in sulfuric acid (H2SO4) may promote both general corrosion and pitting corrosion. The pitting corrosion susceptibility in SS in chlorinated H2SO4 and the effect of Euphorbia echinus extract (EEE) on both general corrosion and pitting corrosion have been studied using potentiodynamic polarization, electrochemical impedance spectroscopy, chronoamperometry, cyclic voltammetry, and scanning electron microscopy (SEM). The pitting potential has been found to shift slightly in the presence of chloride ions (Cl−) in H2SO4. Also, pitting corrosion initiation has been demonstrated in the recorded chronoamperograms as a linear straight line having a positive slope. EEE has reduced the general corrosion and the inhibitor adsorption was found to follow the Langmuir isotherm. SEM micrographs showed that the tested inhibitor has efficiently acted on pitting corrosion for different concentrations of Cl−. Also, the kinetic findings were in good agreement with the surface analysis data. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectrophotometric measurements provided more insights on the interaction between the chemical functional groups of the inhibitor and the SS surface.

Experimental and theoretical investigations of benzoic acid derivatives as corrosion inhibitors for AISI 316 stainless steel in hydrochloric acid medium: DFT and Monte Carlo simulations on the Fe (110) surface

“…Fig. 5a shows the Langmuir adsorption isotherms plotted for 316 SS in inhibited 0.5 M HCl, at 308 K. The reverse of the y-axis intercept, in this gure, yielded K ads in (L mol À1 ), and DG 0 ads in (kJ mol À1 ) was then calculated using eqn (12). The standard Gibbs free energy, DG 0 ads , of adsorption of C1, C2, and C3 on the SS surface were determined and illustrated in Table 5, at 308 K.…”

“…[7][8][9] The application of stainless steel in aggressive environments is subject to corrosion, which generates huge nancial losses in industrial processes. [10][11][12][13] Therefore, it is essential to nd solutions to the corrosion of materials used in aggressive environments.…”

Synthesis, Electrochemical, Thermodynamic, and Quantum Chemical Investigations of Amino Cadalene as a Corrosion Inhibitor for Stainless Steel Type 321 in Sulfuric Acid 1M

“…erefore, the observed features can be explained by the physical adsorption of the inhibitor on the metal surface [24]. e determination of the activation energy E a and enthalpy and entropy of activation (ΔH * a , ΔS * a ) from Arrhenius equations can be found in detail elsewhere [10,[24][25][26][27] and is summarized in Table 6. Figure 5 shows the plot of ln (i corr ) against 1/T in the absence and presence of inhibitor; from the slope (−E a /R), the value of the apparent activation energy is determined.…”

Optimization of Physicochemical Parameters during the Electrocoagulation Cadmium Elimination

“…Indeed, it is followed by a phase of depassivation. e latter is as important as the medium is rich in chloride ions which contribute to the degradation of this layer of alumina by their pitting [22,42,43] corrosive power.…”