Corrosion Inhibition of Mild Steel in 1 M HCl Solution by Poly(o-aminothiophenol) and Poly(o-aminothiophenol)/CuO Nanocomposites

The chemical oxidative polymerization of poly(o-aminothiophenol) and poly(o-aminothiophenol)/ CuO nanocomposites were performed in aqueous HCl using ammonium persulfate as an oxidant. The synthesized polymer and its CuO nanocomposites were characterized by employing FT-IR, UV-Vis and XRD analysis. Weight loss and electrochemical techniques were used to investigate the inhibitory performance of poly(o-aminothiophenol) and poly(o-aminothiophenol)/CuO nanocomposites on mild steel in 1 M HCl solution. The electrochemical impedance spectroscopic method showed a capacitive loop, revealing that the corrosion reaction is governed by the charge transfer mechanism. The inhibitors were of a mixed type, according to polarization measurements. The adsorption process was obeyed by the Langmuir isotherm. The Langmuir adsorption isotherm was also used to derive thermodynamic adsorption parameters.

Electrochemical, Thermodynamic, Surface, and Spectroscopic Study in Inhibition of Iron Corrosion with Turmeric Root Extract (TRE)

Turmeric root extract was tested as corrosion inhibitor for iron in 0.5 M HCl, using potentiodynamic polarization and electrochemical impedance spectroscopy, scanning electron microscope, and energy dispersive X-ray analysis. The inhibition efficiency increases as the time of immersion rises but decreases with temperature rise. The Nyquist plots showed that the charge transfer resistance increases and the double-layer capacitance decreases as the time of immersion increases. Tafel results show that both corrosion current and corrosion speed are reduced with time of immersion. All impedance spectra of EIS tests exhibit one capacitive loop, which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiency increases with the concentration of the inhibitor reaching its maximum value, 88.90%, at 8 g/100 mL. Thermodynamic parameters, Ea, ∆H*, and ∆S*, were estimated, and the mechanism of corrosion and inhibition was discussed. The adsorption of turmeric root extract followed Langmuir adsorption isotherm.

Cistus monspeliensis extract as antioxidant and corrosion inhibitor of ordinary steel in 1 M hydrochloric acid medium

The aim of this study is the valorization of the Cistus monspeliensis plant, native to North of Morocco, as antioxidant and corrosion inhibitor. Firstly, the plant is extracted by maceration in a mixture of water/acetone solvents. Phytochemical tests are carried out on the extract obtained. The antioxidant power of Cistus monspeliensis extract is evaluated by two methods: the test of reduction of the free radical DPPH∙ (1,1-diphenyl-2-picryl hydrazyl) and that of Ferric reducing antioxidant power (FRAP). The electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization are used to study the anticorrosion effect of Cistus monspeliensis extract. The results showed that the extract, 27.6% yield, contains phenolic compounds in the form of flavonoids, hydrolysable and condensed tannins, saponins, reducing sugars and glycosides. This extract has an antioxidant capacity similar to that of ascorbic acid with an inhibition concentration of 0.077 mg/mL 0.102 mg/mL for DPPH and FRAP test, respectively. Tafel plots show that the extract is an excellent cathodic inhibitor. The maximum inhibition efficiency of 92 % was obtained with 0.25 g/L of the inhibitor at 298 k. The impedance plot is characterized by a single capacitive loop attributed to the charge transfer process. The results also showed that the inhibitor acts on the surface of the metal principally by adsorption, leading to the formation of a protective film limiting the corrosion of ordinary steel.

Application of 1,2,3-Benzotriazole as Corrosion Inhibitor for Mild Steel in Sulphuric Acid Medium at Different Temperature

Corrosion inhibition property of 1,2,3-benzotriazole for mild steel in 0.1 N sulphuric acid was evaluated at different concentrations and temperatures using weight loss, electrochemical polarization, differential pulse, stripping voltammetry and impedance spectroscopy. The surface study was carried out using metallurgical research and SEM microscopy. Increase in Warburg impedance and capacitive current and decrease in Faradaic current and capacitive loop was observed with increase in concentration of inhibitor. 1,2,3-Benzotriazole was found as a best corrosion inhibitor (94 %) for mild steel as compared to other inhibitors suggesting 1,2,3-benzotriazole as a potential alternate corrosion inhibitor for mild steel in H2SO4.

Experimental and DFT Investigation on the Corrosion Inhibition of Mild Steel by 1,2,3-Triazolereg Ioisomers in 1M Hydrochloric Acid Solution

1-[(4-ethyl-2-phenyl-4,5-dihydro-1,3-oxazol-4-yl)methyl]-4-phenyl-1H-1,2,3-triazole (Ph4) and1-[(4-ethyl-2-phenyl-4,5-dihydro-1,3-oxazol-4-yl)methyl]-5-phenyl-1H-1,2,3-triazole (Ph5) are new isomers of the triazole derivative family, were synthesized and tested on the corrosion of mild steel in molar hydrochloric acid molar media using weight loss, electrochemical polarization and impedance spectroscopy. Then the experimental results were confirmed by quantum chemical calculations using DFT at B3LYP /6-31G (d,p). The compound Ph4 is the best inhibitor and its inhibitory efficiency increased with increasing concentration and reaching 95% at 10−3 M. Polarization curves studies show that both compounds tested are mixed-type inhibitors. Nyquist curves presented a single capacitive loop, their diameter increases progressively with both inhibitors concentration. The change of the substitution phenyl from position 5 to position 4 in the triazole ring increases the inhibitory effect of the triazole compounds. The effect of temperature on the corrosion behavior of iron indicates that the inhibitory efficiency of the two inhibitors decreases with increasing temperature in the range of 308 to 338K. DFT study is in good correlationwith the experimental results.

A study on the effect of new prepared amide cationic amphipathic on the corrosion inhibition of API N80 steel pipelines in oil wells industries

Purpose The purpose of this study is to inspect the corrosion inhibition of API N80 steel pipelines in uninhibited solution and inhibited with a synthesized surfactant compound [N-(3-(dimethyl octyl ammonio) propyl) palmitamide bromide] (DMDPP), which is prepared through a simple and applicable method. Design/methodology/approach Weight loss was inspected at five different temperatures of 25°C, 30°C, 40°C, 50°C and 60°C Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation were used at room temperature. Density functional theory was used to study the relation between the molecular structure and inhibition theoretically. Findings Adsorption of the prepared DMDPP fits the Langmuir isotherm model. The inhibition efficiency of the prepared DMDPP amphipathic inhibitor is directly proportional to temperature increase. Polarization results reveal that the investigated DMDPP amphipathic compound behaves as a mixed-type inhibitor. EIS spectra produced one individual capacitive loop. Originality/value The originality is the preparation of cationic surfactants through a simple method, which can be used as corrosion inhibitors in oil production. The synthesized inhibitors were prepared from low-price materials. The work studied the behavior of the synthesized surfactants in inhibiting the corrosion of the steel in an acidic medium. Electrochemical and theoretical studies were presented, besides gravimetric and surface examination.

Influence of Nonoxynol-9 on the Corrosion Inhibition of Carbon Steel in 1.0 M Hydrochloric Acid Solution

The inhibitory performance of nonoxynol-9 (N9) as a corrosion inhibitor for carbon steel was evaluated in 1.0 M HCl solution at different temperatures. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and quantum chemical calculation methods were used in this study. The results indicated that the corrosion rate decreased with increasing concentration of N9 up 150 ppm and decreased with the increase in temperature of the medium. The comparison between the results obtained by polarization and EIS methods showed a good agreement. The corrosion inhibition effect of N9 could be related to the adsorption of N9 molecules on the metal surface. Polarization curves indicated that N9 behaves as a mixed type inhibitor. EIS exhibited one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. The inhibition mechanism of N9 involves physical interaction between the inhibitor and metal surface. The adsorption of N9 on carbon steel affords physisorption process and obeyed the Langmuir adsorption isotherm.

Electrochemical Behavior of 430 Ferritic Stainless Steel in HCl Solution with Different Concentration of Hydrochloric Acid

The hydrochloric acid pickling process which is widely applied in carbon steel pickling ensures high speeds with little pollution. In this research, hydrochloric acid pickling process was introduced into stainless steel pickling to improve the surface integrity. Research indicated that the impedance spectrum obtained from 430SS in HCl solution consisted of a capacitive loop at high frequencies and an inductive loop at low frequencies. As the concentration of hydrochloric acid rose, the radiuses of the capacitive loop decreased.And the corrosion potential of 430SS in hydrochloric acid solution moved to positive direction with band to a narrow 0.1V.And high HCl concentration more markedly influenced the charge-transfer resistance.

Electrochemical Impedance Spectroscopy Studies of Corrosion of Two-phase Ni-Dy Alloys in Molten (0.62Li,0.38K)2CO3 at 650 °C

The dissolution of the NiO cathodes and the corrosion of bipolar plates are great obstacles to the commercialization of molten carbonate fuel cells (MCFC). Rare earth element dysprosium is effective in inhibiting the corrosion of Ni in molten carbonates. In this presentation, electrochemical impedance spectroscopy was employed to study the corrosion behavior of two-phase Ni-Dy alloys containing 1 and 3 wt.% Dy, respectively, in molten (0.62Li,0.38K)2CO3 at 650 °C in air. The experimental results indicate that the Nyquist plots for the corrosion of both Ni-1Dy and Ni-3Dy are all composed of a small capacitive loop at high frequencies and a line at low frequencies, but with larger impedance values for Ni-3Dy. The emergence of Warburg impedance at low frequencies suggests that the corrosion of alloys is controlled by the diffusion of oxidants in molten carbonates, as observed for pure nickel. The addition of dysprosium to nickel can decrease its corrosion rate, with a better effectiveness for the 3% Dy addition. Based on the diffusion impedance, the oxidants involved in corrosion are also discussed.