Corrosion inhibition of aluminum with a 3‐(10‐sodium sulfonate decyloxy) aniline monomeric surfactant and its analog polymer in a 0.5M hydrochloric acid solution

The inhibitory effect of a 3‐(10‐sodium sulfonate decyloxy) aniline monomeric surfactant and the analog polymeric surfactant poly[3‐(decyloxy sulfonic acid) aniline] (PC₁₀) on the corrosion of aluminum in 0.5M hydrochloric acid was studied with weight loss and potentiodynamic polarization techniques. The results show that the inhibition occurred through the adsorption of inhibitor molecules on the metal surface. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. It was found that these inhibitors acted as mixed‐type inhibitors with anodic predominance. The adsorption of these compounds on the metal surface obeyed the Langmuir and Frumkin adsorption isotherms. Thermodynamic functions for both the dissolution and adsorption processes were determined. The obtained results from the weight loss and potentiodynamic polarization techniques were in a good agreement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

TERTIARY KETONIC MANNICH BASES AS CORROSION INHIBITORS FOR ALUMINUM DISSOLUTION IN ACIDIC SOLUTIONS

Aluminum corrosion rate was studied in the absence and presence of some tertiary ketonic Mannich bases in 2 M HCl solution, using weight loss and galvanostatic polarization techniques. The two methods gave similar results. The results showed that the inhibitor efficiency increases with increasing inhibitor concentration and decreases with increasing the temperature of the system. The adsorption of these Mannich bases on Al surface is found to obey Temkin's adsorption isotherm. Galvanostatic polarization studies showed that these compounds are mixed-type inhibitors. Some thermodynamic parameters were computed and discussed. Finally, the influence of the chemical structure of the tertiary ketonic Mannich bases on their inhibition efficiencies is discussed.     

Role of some thiadiazole derivatives as inhibitors for the corrosion of C-steel in 1 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript>

Inhibition of C-steel corrosion by some thiadiazole derivatives (I–VI) in 1 M H₂SO₄ was investigated by weight loss, potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) techniques. The presence of these compounds in the solution decreases the double layer capacitance, increases the charge transfer resistance and increase of linear polarization. Polarization studies were carried out at room temperature, and showed that all the compounds studied are mixed type inhibitors with a slight predominance of cathodic character. The effect of temperature on corrosion inhibition has been studied and the thermodynamic activation and adsorption parameters were calculated and discussed. Electrochemical impedance was used to investigate the mechanism of corrosion inhibition. The adsorption of the compounds on C-steel was found to obey Langmuir’s adsorption isotherm. The synergistic effect brought about by combination of the inhibitors and KSCN, KI and KBr was examined and explained. The mechanism of inhibition process was discussed in the light of the chemical structure and quantum-chemical calculations of the investigated inhibitors.     

LOW MOLECULAR WEIGHT STRAIGHT-CHAIN DIAMINES AS CORROSION INHIBITORS FOR SS TYPE 304 IN HCL SOLUTION

The effect of some low molecular weight straight-chain diamines to inhibit the corrosion of SS type 304 in 1 M HCl solution is examined by weight loss and galvanostatic polarization techniques. The inhibition efficiency increases with increasing the number of carbon atoms in the chain up to 8 carbons, but at higher than 8 carbon atoms (12 carbons) it decreases again. These diamine compounds act as mixed-type inhibitors, but the cathode is more polarized than the anode when an external current was applied. The corrosion rate in the presence of the investigated diamine compounds was found to increase with increasing the temperature and decrease with increasing the concentration of these compounds. Activation parameters for the corrosion of SS in 1 M HCl were calculated and showed that corrosion was much reduced in the presence of inhibitors. The adsorption of these compounds on SS from 1 M HCl solution obeys the Langmuir adsorption isotherm. The synergistic effect of KI on the inhibitive efficiency of the investigated diamine compounds was also studied.     

LOW MOLECULAR WEIGHT STRAIGHT-CHAIN DIAMINES AS CORROSION INHIBITORS FOR SS TYPE 304 IN HCL SOLUTION

The effect of some low molecular weight straight-chain diamines to inhibit the corrosion of SS type 304 in 1 M HCl solution is examined by weight loss and galvanostatic polarization techniques. The inhibition efficiency increases with increasing the number of carbon atoms in the chain up to 8 carbons, but at higher than 8 carbon atoms (12 carbons) it decreases again. These diamine compounds act as mixed-type inhibitors, but the cathode is more polarized than the anode when an external current was applied. The corrosion rate in the presence of the investigated diamine compounds was found to increase with increasing the temperature and decrease with increasing the concentration of these compounds. Activation parameters for the corrosion of SS in 1 M HCl were calculated and showed that corrosion was much reduced in the presence of inhibitors. The adsorption of these compounds on SS from 1 M HCl solution obeys the Langmuir adsorption isotherm. The synergistic effect of KI on the inhibitive efficiency of the investigated diamine compounds was also studied.     

Inhibition of corrosion of steel in produced water of Western Desert crude oil

The corrosion inhibition of steel in water from Western Desert (Egypt) crude oil by nine S-alkyl isothioronium halides was studied using open-circuit potential (OCP) measurements and potentiodynamic polarization tests. The objectives were to determine (a) the effect of chain length of the alkyl groups on the inhibition efficiency, (b) the effect of halide counter ion on the performance of the inhibitor, and (c) to apply a recent developed kinetic-thermodynamic model on the data and compare it with common adsorption isotherms. The number of active sites, binding constant and change of free energy of adsorption were computed for all inhibitors studied. The inhibition efficiency was correlated with the molecular structure of the inhibitors. It was found that each organic molecule replaces more than one adsorbed water molecule from the steel surface. Potentiodynamic polarization curves indicated that the compounds acted as mixed-type inhibitors. The OCP measurements showed that adsorption of S-alkyl isothioronium compounds at the steel surface is through two adsorbed layers.     

Influence of substituted benzothiazoles on corrosion in acid solution

Compounds such as 2-aminobenzothiazole (ABT), 2-amino-6-chlorobenzothiazole (ACLBT), 2-amino-6-methyl benzothiazole (AMEBT) and 2-amino-6-methoxy benzothiazole (AMEOBT) have been synthesized and their inhibitive action on the corrosion of mild steel in 1 m HCl has been evaluated using weight loss, potentiodynamic polarization studies and hydrogen permeation measurements. Determination of inhibition efficiency in the presence of these compounds at different temperatures clearly indicates that ACLBT shows the best performance, even at a temperature as high as 60°C. Potentiodynamic polarization studies reveal the fact that ABT and its derivatives act as cathodic inhibitors. All these compounds are found to reduce the permeation of hydrogen through mild steel in HCl solution. The adsorption of these compounds on mild steel from HCl solutions obeys Temkin's adsorption isotherm. The adsorption of 2-amino benzothiazole on the mild steel has been substantiated by Auger electron spectroscopy.     

CORROSION INHIBITION OF MILD STEEL IN 1 N HCL SOLUTION BY MERCAPTO-QUINOLINE SCHIFF BASE

Corrosion inhibition of mild steel in 1 N HCl solutions was investigated in the absence and presence of different concentrations of some mercapto-quinoline derivatives namely, 3-((phenylimino)methyl)quinoline-2-thiol (PMQ) and 3-((5-methylthiazol-2-ylimino)methyl)quinoline-2-thiol (MMQT) by using conventional weight loss, potentiodynamic polarization, linear polarization, electrochemical impedance spectroscopy, and scanning electron microscopic studies. By EIS and weight loss measurements, it was found that PMQ and MMQT were effective inhibitors and their inhibition efficiency was significantly increased with increasing concentrations of inhibitors. Polarization curves showed that the evaluated PMQ and MMQT both act as mixed inhibitions. The adsorptions of these inhibitors on the mild steel were found to follow the Langmuir adsorption isotherm. Results show that the rate of corrosion of mild steel increased with increasing temperature over the range 25°–45°C both in the presence of inhibitors and in their absence. Activation energies in the presence and absence of PMQ and MMQT were obtained.     

Hector bases – a new class of heterocyclic corrosion inhibitors for mild steel in acid solutions

Three heterocyclic compounds namely 3-anilino-5-imino-4-phenyl-1, 2,4-thiadiazoline (AIPT), 3-anilino-5-imino-4-tolyl-1, 2,4-thiadiazoline (AITT), and 3-anilino-5-imino-4-chlorophenyl-1, 2,4-thiadiazoline (AICT) were synthesized and their influence on the inhibition of corrosion of mild steel in 1 M HCl and 0.5 M H₂SO₄ was investigated by weight loss and potentiodynamic polarization techniques. The values of activation energy and free energy of adsorption of these compounds were also calculated. Potentiodynamic polarization studies were carried out at room temperature, and showed that all the compounds were mixed type inhibitors causing blocking of active sites on the metal. The inhibition efficiency of the compounds was found to vary with concentration, temperature and immersion time. Good inhibition efficiency was evidenced in both acid solutions. The adsorption of the compounds on mild steel for both acids was found to obey the Langmuir adsorption isotherm. Electrochemical impedance spectroscopy was also used to investigate the mechanism of corrosion inhibition.     

Electrochemical and theoretical studies of thienyl-substituted amino triazoles on corrosion inhibition of copper in 0.5 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript>

2,5-Bis(2-thienyl)-4-amino-1,2,4-triazole (2-TAT) and 2,5-bis(3-thienyl)-4-amino-1,2,4-triazole (3-TAT) have been studied as inhibitors for the corrosion of copper in 0.5 M H₂SO₄ using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The inhibition efficiency of the triazole compounds increases with increasing concentration, and the effect of 3-TAT is better than that of 2-TAT with the same concentration. Potentiodynamic polarization measurements indicate the triazole compounds act as mixed type inhibitors in 0.5 M H₂SO₄. The adsorption of the triazole compounds is found to obey the Langmuir adsorption isotherm. High significant correlations for the triazole compounds are obtained between inhibition efficiency and quantum chemical parameters (R = 0.975) using the quantitative structure–activity relationship (QSAR) method.     

Experimental and theoretical studies of anti-ulcer drugs with benzimidazole rings as corrosion inhibitor for copper in 1 M nitric acid medium

The adsorption effect of esomeprazole (ESP) and lansoprazole (LP) on corrosion behavior of copper in 1 M HNO₃ solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The experimental results indicate that both ESP and LP inhibited the corrosion of copper in nitric acid solution and the inhibition efficiency increased as the concentration of the compounds increased. EIS measurements confirmed that the charge transfer resistance increases on increasing the inhibitor concentration. Polarization measurements showed that the inhibitors are of mixed type. From the weight loss measurements, the inhibition efficiency of the inhibitors was found to vary with concentration, immersion time, and temperature. The adsorption of inhibitors on the copper surface follows Langmuir isotherm. The surface morphology was examined by scanning electron microscope and atomic force microscope. Further, the computational calculations are performed to find a relation between their electronic and structural properties.     

Antibacterial drugs as inhibitors for the corrosion of stainless steel type 304 in HCl solution

The effect of three antibacterial drugs (3-thiazinonyl-bicyclo [4.2.0] octene-carboxylate derivatives) on the corrosion behavior of stainless steel type 304 in 1.0 M HCl solution has been investigated using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency increased with increase in inhibitor concentration but decreased with increase in temperature. The thermodynamic functions of corrosion and adsorption processes were evaluated. The potentiodynamic polarization measurements indicated that the inhibitors are of mixed type. The adsorption of these inhibitors was found to obey Langmuir’s adsorption isotherm. Synergism between iodide ion and inhibitors was proposed. The inhibitive action was satisfactory explained by using both thermodynamic and kinetic models. The results obtained from the three different techniques were in good agreement.     

Inhibition of mild steel corrosion in sulfuric acid solution by thiadiazoles

Four heterocyclic compounds namely 2-amino-1,3,4-thiadiazoles (AT), 5-Methyl-2-amino-1,3,4-thiadiazoles (MAT), 5-Ethyl-2-amino-1,3,4-thiadiazoles (EAT) and 5-Propyl-2-amino-1,3,4-thiadiazoles (PAT) were synthesized and their influence on the inhibition of corrosion of mild steel (MS) in 0.5 M H₂S0₄ was investigated by weight loss and potentiodynamic polarization techniques. The values of activation energy, free energy of adsorption, heat of adsorption, enthalpy of activation and entropy of activation were also calculated to investigate the mechanism of corrosion inhibition. Potentiodynamic polarization studies were carried out at room temperature, and showed that all the compounds studied are mixed type inhibitors causing blocking of active sites on the metal. The inhibition efficiency of the compounds was found to vary with concentration, temperature and immersion time. Good inhibition efficiency was evidenced in the sulfuric acid solution. The adsorption of the compounds on mild steel for sulfuric acid was found to obey Langmuir’s adsorption isotherm. FT–IR spectroscopic studies were also used to investigate the purity of compounds synthesized.     

The Effect of Non Ionic Surfactants Containing Triazole, Thiadiazole and Oxadiazole as Inhibitors of the Corrosion of Carbon Steel in 1M Hydrochloric Acid

In the present investigation novel nonionic surfactants were synthesized, characterized and tested as inhibitors of the corrosion of carbon steel in 1M HCl solution. The inhibition action of these surfactants was studied by weight loss, galvanostatic polarization and electrochemical impedance spectroscopy. The adsorption of the inhibitors was well described by the Langmuir adsorption isotherm and the adsorption isotherm parameters were determined at different temperatures. The inhibition efficiency was found to rise when increasing the concentration of these compounds and decreasing the temperature. The effect of temperature on the inhibition efficiency of the corrosion process was studied and the values of some activated thermodynamic parameters were calculated to elaborate the mechanism of inhibition. The synthesized nonionic surfactants exhibit good surface and antimicrobial properties.     

Corrosion inhibition effect of pyrazole derivatives on mild steel in hydrochloric acid solution

Synthesized compounds, namely methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate (MCPPC) and 5-(4-methoxyphenyl)-3-(4-methylphenyl)4,5-dihydro-1H-pyrazol-1-yl-(pyridin-4-yl)methanone (MMDPPM) were investigated as corrosion inhibitor for mild steel (MS) in 15% HCl solution using weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods. Inhibition efficiency was found concentration-dependent and increased by increasing the concentration of MCPPC and MMDPPM. Both of inhibitors were efficient even at a very low concentration of 25 ppm. The inhibitors MCPPC and MMDPPM showed inhibition efficiency of 67.1 and 76.8%, respectively, at 25 ppm, whereas it was 92.0 and 95.9%, respectively, at 250 ppm concentration at 303 K. The potentiodynamic polarization curves showed that MCPPC and MMDPPM act as mixed-type inhibitor in 15% HCl solution. The Nyquist plots showed that charge transfer resistance increased and double-layer capacitance decreased on increasing the concentration of studied inhibitors due to adsorption of inhibitor molecules on MS surface. The adsorption of each inhibitor on MS surface obeys Langmuir adsorption isotherm. On the basis of thermodynamic adsorption parameters, mixed-type adsorption (physisorption and chemisorption) for the studied inhibitors on MS surface was suggested. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM) analyses confirmed the existence of a protective film of the inhibitor on MS surface. The density functional theory was employed for theoretical calculations, and the obtained results were found to be consistent with the experimental findings.     

CORROSION INHIBITION OF CuNi10Fe ALLOY WITH PHENOLIC ACIDS

The purpose of this study was to investigate the efficiency of two phenolic acids, namely p-hydroxybenzoic acid (HBA) and protocatechuic acid (PCA), as corrosion inhibitors for CuNi10Fe alloy in a 0.5 mol dm^?3 NaCl solution. In these investigations, open circuit potential measurements, potentiodynamic polarization measurements, and the linear polarization method have been used. It was found that both phenolic acids had similar corrosion inhibition effects on the CuNi10Fe alloy dissolution. The inhibition efficiency (IE) increased with increase in inhibitor concentration. The polarization shows that both compounds functioned as cathodic corrosion inhibitors by adsorption on the surface of CuNi10Fe alloy according to the Freundlich adsorption isotherm. The numerical values of free energies of adsorption indicate physical adsorption of the compounds on the electrode surface. DFT-based quantum chemical computations and molecular dynamics (MD) simulations revealed identical electronic and adsorption structures for both HBA and PCA, which could account for the similarities in the experimentally observed inhibiting effects.     

Corrosion inhibition and adsorption properties of cerium-amino acid complexes on mild steel in acidic media: Experimental and DFT studies

Abstract

The corrosion inhibition and adsorption behavior of glutamic acid (Glu), glutamine (Gln), and their cerium complexes: cerium glutamate (Ce(Glu)) and cerium glutamine (Ce(Gln)) on mild steel in 0.5?M HCl solutions were studied at 25 and 55?°C and concentration range of 25–200?ppm using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopic (EIS) techniques. The inhibition efficiency was found to be dependent on the concentration and temperature of the system. The potentiodynamic polarization results suggest that the compounds act as mixed-type inhibitors with dominant cathodic inhibition. The mechanism of adsorption deduced from the variation of inhibition efficiency with temperature, as well as the activation parameters, suggest significant physisorption of the inhibitor molecules on the metal surface. The experimental data adhere to the Langmuir and El-Awady et al. kinetic adsorption models. The extent of inhibition was found to be Ce-Gln?>?Gln and Ce-Glu?>?Glu. The scanning electron microscope was employed for the morphological studies and the characteristic of the protective layer on the steel surface verified using UV-Vis spectroscopy and FTIR spectroscopy. Adsorption of the inhibitors on Fe (110) surface was evaluated theoretically.     

NEW ARYLAZODYES AS CORROSION INHIBITORS FOR MILD STEEL IN HCl SOLUTION

Five arylazocyanoacetamide derivatives were investigated as corrosion inhibitors of mild steel in 2 M HCl solution using weight loss and galvanostatic polarization techniques. The inhibiting properties were found to depend on the concentration, the temperature, and the molecular structure of the compounds. Enhancement in inhibition efficiency of these compounds was observed on addition of KSCN due to synergism. The inhibitive action may be attributed to adsorption of inhibitor molecules on the active sites of the metal surface following the Frumkin adsorption isotherm. Thermodynamic parameters for the corrosion of mild steel in the presence and absence of the arylazocyanoacetamide derivatives have been calculated. Polarization curves indicate that these compounds act as mixed-type inhibitors. The correlation between inhibition efficiency and quantum chemical parameters has been investigated by PM3 quantum chemical calculation.     

Empirical and theoretical investigations on the corrosion inhibition characteristics of mild steel by three new Schiff base derivatives

Synthesis, adsorption and corrosion inhibiting effect of three new Schiff base compounds on mild steel in 1.0?M HCl were explored using weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization techniques. The empirical results showed that three Schiff base compounds inhibited the corrosion reaction in aggressive acid medium. Impedance results indicate that the three organic compounds were adsorbed on the mild steel/solution interface, while polarization data show that the three compounds performed typically as a mixed-type inhibitor. A theoretical study of the adsorption performance of some of the components of Schiff base inhibitors was carried out in the basis of the density functional theory (DFT) and Monte Carlo simulations.     

Synthesis,Surface Properties,and Inhibiting Action of Novel Nonionic Surfactants on Carbon Steel Corrosion in 1 M Hydrochloric Acid Solution

In the present study novel nonionic surfactants were synthesized, characterized, and tested as corrosion inhibitors for carbon steel in 1 M HCl solution. The inhibiting performances of these surfactants were studied by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The adsorption of these inhibitors was well described by Langmuir adsorption isotherm, and the kinetic parameters were calculated and discussed. The inhibition efficiency (IE) was found to rise with increasing the concentration of these inhibitors. Polarization measurements revealed that the inhibitors acted as mixed-type inhibitors. The efficiencies obtained from the impedance measurements were in good agreement with those obtained from the weight loss and potentiodynamic polarization techniques which prove the validity of these tools in the measurements of the tested inhibitors. The surface parameters of the synthesized nonionic surfactants were investigated and the results showed that these surfactants have lower values of surface tension and are effective as wetting and emulsifying agents.