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The purpose of this paper is to investigate the inhibition effect of 2‐aminoethane thiol hydrochloride, 2‐cystamine dihydrochloride, 2,3‐dimercapto‐1‐propanol, 1,2‐ethanedithiol, and the synergistic effect of these compounds with halide ions (Cl⁻, Br⁻, I⁻) and with some metal cations (Co^2 +, Ni^2 +, Cu^2 +, Zn^2 +).

The inhibiting effect of the studied thiols on the corrosion of carbon steel in 0.5 M H₂SO₄ solution were investigated using potentiodynamic polarisation, electrochemical impedance spectroscopy and linear polarisation methods.

The inhibition action of thiols depends mainly on the type of the heteroatom present in the inhibitor molecule. The increase in inhibition efficiencies with increase in inhibitor concentration revealed that the studied compounds were adsorbed onto steel surfaces and the adsorption mechanism obeyed the Langmuir adsorption isotherm. Polarisation curves indicated that thiols containing both N and S atoms in their structure behaved as mixed type inhibitors, while thiols containing only an S atom in their structure acted essentially as anodic inhibitors. The increase in the inhibition efficiencies of thiols with the addition of halide ions indicates that halides play important role in the adsorption process. The synergistic effect of the studied metal cations could be explained by the adsorption of complex ions formed from thiol molecules and metal cations.

This paper provides useful information about the relationship between inhibition efficiencies and the structures of thiols and clarifies the mechanism of the synergistic effects of some halides and some metal cations.

The influence of pyridinium chloride (PC) and n‐hexa decyl pyridinium chloride (HDPC) on the corrosion of mild steel in 5N HCl and 5N H₂SO₄ has been studied using techniques such as weight loss and gasometric measurements, potentiodynamic polarisation studies, linear polarisation studies and small amplitude cyclic voltametric studies. It is found that HDPC is more inhibitive than PC and both the compounds perform better in H₂SO₄. Polarisation studies reveal that PC behaves as an anodic inhibitor in H₂SO₄ and as a mixed inhibitor in HCl. Measurements of values of polarisation resistance (R_p) and double layer capacitance (C_dl) in the presence of these compounds also reveal the better performance of HDPC in both the acids. The adsorption of PC and HDPC on a mild steel surface from both the acids is found to obey Temkin’s adsorption isotherm.

The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m² in simulated soil solution.

The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy.

The results showed that E-I polarization curves under 200-1,200 A/m² interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution.

All tests were conducted at a relative higher DC density (200-1,200 A/m²). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.

The purpose of this paper is to investigate the inhibiting properties of six quaternary ammonium salts, three cationic surfactants and two non‐ionic surfactants in 2 M KOH. An attempt also was made to correlate some molecular parameters of these compounds with their corrosion inhibitor efficiency.

The inhibition efficiencies of quaternary ammonium salts, cationic surfactants and non‐ionic surfactants on the corrosion of zinc in 2 M KOH solution were investigated by potentiodynamic polarisation, electrochemical impedance spectroscopy and linear polarisation methods.

Inhibition efficiencies of quaternary ammonium salts were found to be due to physical absorption on the cathodic sides of zinc electrode and dependence of inhibition efficiencies on substituents were found. Physical adsorption of cationic surfactants on zinc electrode slowed down both anodic and cathodic reactions; thus they were found to be mixed type inhibitors. On the other hand, inhibition behaviour of non‐ionic surfactants was found to be due to adsorption on zinc via polar groups. It was found that non‐ionic surfactants behaved as mixed type inhibitors.

Clarifies the role of molecular structure and substituents on the inhibition efficiency of surfactants and quaternary ammonium compounds on the corrosion of zinc in alkaline media.

The synergistic influence caused by iodide ions on the inhibition of corrosion of mild steel in 0.5M H₂SO₄ in the presence of n‐hexyl amine (n‐HA) has been studied using potentiodynamic polarization, linear polarization and a.c impedance technique. n‐HA accelerates the corrosion of mild steel at lower concentrations but inhibits the corrosion at higher concentrations. The addition of iodide ions enhances the inhibition efficiency to a considerable extent. The adsorption of this compound is found to obey Temkin’s adsorption isotherm. The increase in surface coverage in the presence of iodide ions indicates that iodide ions enhance the adsorption of n‐HA on the metal surface. Defines and evaluates synergism parameter (S_I). Values of the parameter which are more than unity indicate the fact that the enhanced inhibition efficiency in the presence of iodide ions is only due to synergism and there is a definite contribution from the inhibitor molecule. n‐HA is then adsorbed by coulombic interaction on the metal surface, where iodide ions are already adsorbed, and thus reduces the corrosion rate.

The paper aims to highlight the efficiency of double complex numbers for the complete analysis of the intensity of the electric field produced by power lines.

One set of complex numbers is used to represent all the plane vectors (vector distances) and another set of complex numbers is used to represent all the sinusoidal time varying quantities (electric charges and voltages). The simultaneous representation of vector distances and sinusoidal time varying quantities with complex numbers gives elegant expressions to the electric field vector and simplifies the mathematical relations to a great degree.

General analytical formulas are developed for the direct calculation of all the parameters of the elliptically rotating electric field (rms value, major and minor semi‐axis of the ellipse, angles of the semi‐axes, tracing direction, polarization). The analytical formulas depend on the components of the double complex number.

The proposed method can be applied only on 2D problems, especially power lines where the electric field vector can be expressed as a double complex number.

Double complex numbers are proved in this paper as a very effective mathematical tool for the complete analysis of the electric field produced by power lines. The expression of the electric field vector as a double complex number allows the direct calculation of all the parameters of the electric field with analytical relations.

The purpose of this study was to investigate the effects of deformation-induced martensite on electrochemical corrosion behaviors of 304 austenitic stainless steel in a simulated primary water environment of a pressurized water reactor nuclear power plant with boric acid and lithium hydroxide contaminated with chloride by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Mott–Schotty curves and X-ray photoelectron spectroscopy (XPS).

The effects of deformation-induced martensite transformation on electrochemical corrosion behaviors of 304 austenitic stainless steel was investigated in a simulated primary water environment of a pressurized water reactor nuclear power plant with boric acid and lithium hydroxide contaminated with 0.1 M Cl⁻ by potentiodynamic polarization, EIS, Mott–Schotty curves and XPS in this paper.

The results revealed that the martensitic phase contents increased with the level of cold deformation. The general corrosion current density and the corrosion potential increased and decreased, respectively, with the increase of cold deformation degree. However, the pitting potential decreased as the cold deformation increased up to 20 per cent, then a slight increase was observed at 35 per cent cold working. It was found from Mott–Schottky curves and XPS analysis that as the cold deformation degree increased from 0 to 35 per cent, the doping concentrations of the oxide films increased; however, the film thickness decreased, which indicates that both density and integrity of the films are degraded significantly as the deformation degree increases, and this ultimately contributes to the significant increment of the general corrosion rate and reduction of the pitting corrosion resistance.

The effects of deformation-induced martensite transformation on electrochemical corrosion behaviors of 304 austenitic stainless steel was investigated in a simulated primary water environment of a pressurized water reactor nuclear power plant with boric acid and lithium hydroxide contaminated with 0.1 M Cl⁻ by potentiodynamic polarization, EIS, Mott–Schotty curves and XPS in this paper.

The purpose of this study is to explore the influence of the sulfate reducing bacteria (SRB) on the corrosion of cupronickel.

Tests monitoring the change in free corrosion potential, linear polarization resistance and electrochemical impedance spectroscopy and examination using the scanning electron microscope and energy spectrum analysis were used to investigate the corrosion behavior of cupronickel in blank medium and in media inoculated with SRB to explore the influence of the SRB on the corrosion behavior of cupronickel alloy.

The results show that SRB can destroy the surface oxide film of cupronickel and significantly reduce the free corrosion potential and polarization resistance of the cupronickel, causing the cupronickel to corrode significantly.

SRB are widely found in the water supply system and is one of the important factors inducing microbial corrosion. This paper verified that SRB promote cupronickel corrosion and explored the influence and mechanism of attack.

The purpose of this investigation is the evaluation of the inhibitive performance of a new “gemini” surfactant in the series of bis‐quat: N, N, N′, N″, N″‐pentamethyl diethyleneamine‐N, N″‐di‐[tetradecylammonium bromide] on the corrosion of iron in 1 M HCl by gravimetric, potentiodynamic and electrochemical impedance measurements. The effect of the temperature on the corrosion behavior of iron in 1 M HCl without and with inhibitor is studied in the temperature range (298‐333 K). This work also attempts to correlate thermodynamic and kinetic parameters with the inhibition effect.

The inhibition efficiency of gemini synthesized is investigated by weight loss, potentiodynamic polarization and impedance spectroscopy methods.

The synthesized gemini bis‐quat acted as a good inhibitor in 1 M HCl, and inhibition efficiency increased with inhibitor concentration and temperature. Polarization curves showed that the surfactant was a mixed‐type inhibitor in hydrochloric acid. Impedance spectroscopy measurements showed that the inhibitor acted through the formation of a multilayer film at the iron surface. The adsorption of inhibitor on the iron surface obeyed the Langmuir adsorption isotherm equation. The inhibition effect was satisfactorily explained by both thermodynamic and kinetic parameters.

The adsorption of surfactants in the metal surface can markedly change the corrosion resisting property of the metal. So the study of the relation between the adsorption and corrosion inhibition is of a great importance. This was the first attempt to study the inhibition properties of gemini surfactants at the host laboratory.

The purpose of this paper is to report the electrochemical verification of anticorrosive properties of NiZn ferrites as pigments in protective coatings and evaluation of their microwave absorbing properties.

Ferrites, represented by formula Ni_xZn_(1−x)Fe₂O₄, where x=0, 0.2, 0.4, 0.6, 0.8, 1.0, were synthesized using a ceramic method. The samples of ferrites were examined by X‐ray diffraction and SEM. Immersion tests in ferrite extracts, combined with electrochemical tests using techniques such as polarization curves, linear polarization and electrochemical impedance spectroscopy (EIS) were involved to determine the protective action provided by the ferrites. Epoxy coatings containing 10 vol.% of the ferrite were investigated using EIS. Experimental verification is provided of the microwave attenuation capability of coatings containing the investigated ferrites. Reflection loss, measured in the frequency range of 6.5‐15 GHz, exhibited maximum attenuation at a level of 8‐16 dB.

The results obtained suggest that NiZn ferrites possess active anticorrosive properties and support inhibition of the cathodic reaction by scale deposition at the metal substrate in an alkaline environment created by the pigments and the cathodic reaction. Additionally, they can serve as a microwave suppressor.

NiZn pigments can be used in coatings to serve simultaneously as an active anticorrosion, non‐toxic pigment and a material protecting against electromagnetic interference problems.

The paper provides information regarding the anticorrosive properties of NiZn ferrites as pigments for protective coatings and also microwave absorbing materials. An attempt was made to elucidate the potential mechanism of anticorrosive action of these pigments.