scholarly journals Electrochemical Study on Corrosion Inhibition of Copper in Hydrochloric Acid Medium and the Rotating Ring-Disc Voltammetry for Studying the Dissolution

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
A. K. Satpati ◽  
A. V. R. Reddy
Keyword(s):  
Hydrochloric Acid ◽  
Acid Medium ◽  
Corrosion Inhibition ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Standard Free Energy ◽  
Charge Transfer Resistance ◽  
Standard Free Energy Change ◽  
Transfer Resistance ◽  
Hydrochloric Acid Medium

Dissolution characteristics of copper in hydrochloric acid medium and the effect of 4-amino 1,2,4-triazole (ATA) on the corrosion process have been studied using conventional electrochemical techniques and rotating ring-disc electrodes (RRDEs). Corrosion potential () and corrosion current density () were obtained by Tafel extrapolation methods. Charge transfer resistance () and double-layer capacitance () were obtained from the electrochemical impedance spectroscopy (EIS). ATA was shown to be an effective inhibitor for the copper-corrosion inhibition in acid medium. The corrosion rate was retarded in presence of inhibitors mainly because of the adsorption of the inhibitor on the electrode surface. Adsorption of the inhibitor on the metal surface was found to follow the Langmuir adsorption isotherm. Standard free energy change of the adsorption process () was calculated to be −54.3 kJ mol−1; such a large negative value of suggests the prescence of a chemisorption process.

THE INFLUENCE OF GRAIN SIZE OF PURE IRON METAL ON CORROSION INHIBITION IN PRESENCE OF SODIUM NITRITE

2012 ◽  
Vol 05 ◽  
pp. 793-800 ◽  
Author(s):  
VAHID AFSHARI ◽  
CHANGIZ DEHGHANIAN
Keyword(s):  
Grain Size ◽  
Aqueous Solutions ◽  
Corrosion Inhibition ◽  
Sodium Nitrite ◽  
Active Sites ◽  
Electrochemical Impedance ◽  
Standard Free Energy ◽  
Charge Transfer Resistance ◽  
Free Energy Of Adsorption ◽  
Transfer Resistance

The effects of grain size reduction on the corrosion inhibition of sodium nitrite were investigated using polarization curves and electrochemical impedance spectroscopy (EIS). Nanocrystalline iron (~ 45 nm) was produced by pulse electrodeposition using citric acid bath. The grain size of a nanocrystalline surface was analyzed by X-ray diffractometry (XRD) and field emission scanning electron microscopy (FESEM). The most intensive first-order peak (211) of the XRD patterns was taken for detailed analysis using a Gaussian fitting curve. The tests were carried out in 25 mg / l NaCl + 57 mg / l Na 2 SO 4 with different concentration of sodium nitrite aqueous solutions. The results revealed that due to the adsorption process which leads to the formation of a protective layer with a greater charge transfer resistance the inhibition effect and corrosion protection of sodium nitrite inhibitor in near-neutral aqueous solutions increased as the grain size decreased from microcrystalline to nanocrystalline. The standard free energy of adsorption ( ΔGads ) revealed a strong interaction between inhibitor and nanocrystalline surface. This was attributed to the increased number of the active sites caused by nanocrystalline surface.

scholarly journals New triazepine carboxylate derivatives: correlation between corrosion inhibition property and chemical structure

2020 ◽  
Vol 11 (1) ◽  
pp. 23-42 ◽  
Author(s):  
K. Alaoui ◽  
Y. El Kacimi ◽  
M. Galai ◽  
H. Serrar ◽  
R. Touir ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Hydrochloric Acid ◽  
Impedance Spectroscopy ◽  
Mild Steel ◽  
Acid Medium ◽  
Corrosion Inhibition ◽  
Electrochemical Impedance ◽  
Protective Film ◽  
Hydrochloric Acid Medium ◽  
Inhibition Property

AbstractIn this investigation, attempts have been made to study the corrosion inhibition properties of three new triazepine carboxylate compounds for mild steel in 1.0 M hydrochloric acid medium. The evaluation was carried out using mass loss, electrochemical impedance spectroscopy and polarization curves measurement. Impedance diagrams and Bode plots for uninhibited and inhibited systems were analyzed using Zview program. The fitted data observed trails in nearly the same pattern as the experimental results. It is showed that triazepine carboxylate compounds are very good inhibitors for mild steel corrosion in 1.0 M hydrochloric acid medium which act as mixed-type inhibitors. So, the inhibition efficiency was increased with inhibitor concentration in the order Cl–Me–CN > Me–CN > Cl–Me–CO2Et which depended on their molecular structures. Electrochemical impedance spectroscopy showed that all compounds act by the formation of a protective film at the metal surface. Surface analyses via SEM and Optical 3D profilometry were used to investigate the morphology of the steels before and after immersion in 1.0 M HCl solution containing inhibitors. The correspondence between inhibition property and molecular structure of the triazepine carboxylate compounds was investigated, using density functional theory (DFT). Experimental and DFT study was further supported by molecular dynamic simulations study.

scholarly journals Synergistic Effect of Iodide Ion and 4-Hydroxy Coumarin on the Corrosion Inhibition of Mild Steel in Hydrochloric Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Shyamala R. Krishnamurthy ◽  
Meenakshi H. N. Parameswaran
Keyword(s):  
Hydrochloric Acid ◽  
Mild Steel ◽  
Mass Loss ◽  
Corrosion Inhibition ◽  
Electrochemical Techniques ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Hydroxy Coumarin ◽  
Loss Method

No discussion of the use of inhibitors in acid solution is complete without mentioning the phenomenon of synergism. Synergism also operates in corrosion protection where an enhanced inhibition may be related to interaction between inhibitor compounds. This effect has been observed since the earlier days of inhibitor technology and continues to be a potent tool in the development of acid inhibitors for specialized uses. Hence, in this paper, the corrosion inhibition behavior of mild steel (MS) in 1 M hydrochloric acid in the presence of 4-hydroxy coumarin (4HC) and potassium iodide (KI) has been investigated using the mass loss method and electrochemical techniques. The inhibitive performance of 4HC is considerably enhanced by the addition of KI. The addition of KI to different concentrations of 4HC has intensified its efficiency through considerable reduction in the mass loss, corrosion current density , double layer capacitance , and increase in charge transfer resistance . The calculated synergism parameter “” is greater than unity, thereby proving the fact that the improvement in inhibition efficiency of 4HC, generated by the addition of KI, is due to synergism.

CORROSION INHIBITION OF ZINC IN HYDROCHLORIC ACID MEDIUM USING UREA INHIBITOR

2007 ◽  
Vol 10 (2) ◽  
pp. 31-38 ◽  
Author(s):  
Khulood AL-Saadie ◽  
◽  
Nadia Abdul Karime ◽  
Israa M Al-Mousawi ◽  
◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Acid Medium ◽  
Corrosion Inhibition ◽  
Hydrochloric Acid Medium

scholarly journals Combined Experimental and Theoretical Insights into the Corrosion Inhibition Activity on Carbon Steel Iron of Phosphonic Acids

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 135
Author(s):  
Aurelia Visa ◽  
Nicoleta Plesu ◽  
Bianca Maranescu ◽  
Gheorghe Ilia ◽  
Ana Borota ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Energy Gap ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Phosphonic Acids ◽  
Transfer Resistance ◽  
Potential Map ◽  
Chlorine Ions

The inhibition effect of N,N′-phosphonomethylglycine (PMG) and vinyl phosphonic acid (VPA) on the 3% NaCl acidic solution corrosion of carbon steel iron was studied at different immersion times by potentiodynamic polarization, electrochemical impedance spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and computational methods. It is found from the polarization studies that PMG and VPA behave as mixed-type inhibitors in NaCl. Values of charge transfer resistance (Rct) and double layer capacitance (Cdl) in the absence and presence of inhibitors are determined. The PMG and VPA inhibitors were capable of inhibiting the corrosion process up to ≈91% and ≈85%, respectively. In the presence of PMG, the synergic effect of chlorine ions was observed. Density functional theory (DFT) was engaged to establish the adsorption site of PMG, VPA, and their deprotonated states. For studied compounds, the resulted values of ELUMO, EHOMO, energy gap (∆E), dipole moment (μ), electronic hardness (η), global softness (σ), electrophilic index (ω), and the electronic potential map are in concordance with the experimental data results regarding their corrosion inhibition behavior and adsorption on the metal surface.

scholarly journals Inhibition Effect of Miconazole Nitrate on the Corrosion of Mild Steel in Hydrochloric Acid Medium

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
J. Ishwara Bhat ◽  
Vijaya D. P. Alva
Keyword(s):  
Hydrochloric Acid ◽  
Mild Steel ◽  
Acid Medium ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Inhibitor Molecule ◽  
Langmuir Adsorption ◽  
Hydrochloric Acid Medium ◽  
Miconazole Nitrate ◽  
Impedance Spectroscopy Technique

The corrosion inhibition of mild steel by miconazole nitrate, an antifungal drug has been investigated using potentiodynamic polarization, electrochemical impedance spectroscopy technique, and weight loss methods. The experimental results suggested miconazole nitrate is a good corrosion inhibitor for mild steel in 1 M hydrochloric acid medium. The inhibition efficiency increased with increase in inhibitor concentration. The thermodynamic parameters were determined and discussed. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the surface of mild steel following Langmuir adsorption isotherm.

Some Anionic Surfactants as Corrosion Inhibitors for Carbon Steel in Hydrochloric Acid Solution

2018 ◽  
Vol 786 ◽  
pp. 134-148 ◽  
Author(s):  
Rania Assem ◽  
A.S. Fouda ◽  
A.A. Ibrahim ◽  
M. Saadawy
Keyword(s):  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Hydrochloric Acid Solution ◽  
Anionic Surfactants ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Polarization Data ◽  
Transfer Resistance ◽  
Carbon Steel Surface

The corrosion inhibition effect of some anionic surfactants (Diisononyl phthalate (A), N-oleyl-1, 3-propane –diamine (B), and Sodium lauryl sulphate (C)) on the corrosion of carbon steel in 1M hydrochloric acid solution were studied by chemical method (weight loss) and electrochemical methods (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). From the results, it was clear that these surfactants are good inhibitors for corrosion of carbon steel in 1M HCl solution. Their inhibition depends mainly on their concentrations and temperature of solution. Polarization data revealed that these surfactants act as mixed type inhibitors. The surfactants adsorptions were found to follow Langmuir’s adsorption isotherm. The thermodynamic parameters of activation and adsorption were calculated and discussed. Adsorption of used surfactants led to a reduction in the double layer capacitance (Cdl) and an increase in the charge transfer resistance (Rct). All measurements used confirmed the adsorption of the surfactants used on carbon steel surface. Confirmation of these various independent techniques proved validity of the obtained data.

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