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Mohammed A Amin - One of the best experts on this subject based on the ideXlab platform.
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a newly synthesized sulphated 8 hydroxyquinoline derivative to effectively control aluminum corrosion in perchloric acid electrochemical and positron annihilation studies
Journal of Molecular Liquids, 2016Co-Authors: Mohammed A Amin, Mohamed R E Aly, H Shokry, T SharsharAbstract:Abstract The corrosion of aluminum in 1.0 M HClO4 was effectively controlled by a newly synthesized sulphated 8-hydroxy-quinoline derivative (8HQD), namely 2-(2-(quinolin-8-yloxy)acetamido)ethyl hydrogen sulfate. Rates of corrosion were monitored as a function of C8HQD (C8HQD: 10− 4–10− 2 M) using Tafel Extrapolation method and linear polarization resistance (LPR) measurements. The electron density and corrosion-related defects in corroded and inhibited Al samples were probed using the positron annihilation lifetime (PAL) and positron annihilation Doppler broadening (PADB) techniques. Results were compared with 8-hydroxyquinoline (8HQ) itself. Polarization studies indicated that 8HQD acted as a mixed-type inhibitor with anodic predominance. PAS measurements demonstrated that the PAL components (τi) and their corresponding intensities (Ii) as well as PADB line-shape parameters (S and W) can be used to assess the inhibition performance of the tested materials. Results obtained from the different corrosion evaluation techniques were in good agreement and went parallel with those of PAS measurements. 8HQD was much better than 8HQ in inhibiting Al corrosion in these solutions.
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corrosion and corrosion control of mild steel in concentrated h2so4 solutions by a newly synthesized glycine derivative
Corrosion Science, 2011Co-Authors: Mohammed A Amin, Mohamed M IbrahimAbstract:Abstract A newly synthesized glycine derivative (GlyD1), 2-(4-(dimethylamino)benzylamino)acetic acid hydrochloride, was used to control mild steel corrosion in 4.0 M H 2 SO 4 solutions at different temperatures (278–338 K). Tafel Extrapolation, linear polarization resistance (LPR) and impedance methods were used to test corrosion inhibitor efficiency. An independent method of chemical analysis, namely ICP-AES (inductively coupled plasma atomic emission spectrometry) was also used to test validity of corrosion rate measured by Tafel Extrapolation method. Results obtained were compared with an available glycine derivative (GlyD2) and glycine (Gly). Tafel polarization measurements revealed that the three tested inhibitors function as mixed-type compounds. The inhibition efficiency increased with increase in inhibitor concentration and decreased with temperature, suggesting the occurrence of physical adsorption. The adsorptive behaviour of the three inhibitors followed Temkin-type isotherm and the standard free energy changes of adsorption ( Δ G ads o ) were evaluated for the three tested inhibitors as a function of temperature. The inhibition performance of GlyD1 was much better than those of GlyD2 and Gly itself. Results obtained from the different corrosion evaluation techniques were in good agreement.
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monitoring corrosion and corrosion control of iron in hcl by non ionic surfactants of the triton x series part ii temperature effect activation energies and thermodynamics of adsorption
Corrosion Science, 2011Co-Authors: Mohammed A Amin, M A Ahmed, H A Arida, Taner Arslan, Murat Saracoglu, Fatma KandemirliAbstract:Abstract The inhibition characteristics of non-ionic surfactants of the TRITON-X series, namely TRITON-X-100 (TX-100), TRITON-X-165 (TX-165) and TRITON-X-305 (TX-305), on the corrosion of iron was studied in 1.0 M HCl solutions as a function of inhibitor concentration (0.005–0.075 g L−1) and solution temperature (278–338 K). Measurements were conducted based on Tafel Extrapolation method. Electrochemical frequency modulation (EFM), a non-destructive corrosion measurement technique that can directly give values of corrosion current without prior knowledge of Tafel constants, is also presented. Experimental corrosion rates determined by the Tafel Extrapolation method were compared with corrosion rates obtained by the EFM technique and an independent method of chemical analysis. The chemical method of confirmation of the corrosion rates involved determination of the dissolved cation, using ICP-AES (inductively coupled plasma atomic emission spectrometry). The aim was to confirm validation of corrosion rates measured by the Tafel Extrapolation method. Results obtained showed that, in all cases, the inhibition efficiency increased with increase in temperature, suggesting that chemical adsorption occurs. The adsorptive behaviour of the three surfactants followed Temkin-type isotherm. The standard free energies of adsorption decreased with temperature, reflecting better inhibition performance. These findings confirm chemisorption of the tested inhibitors. Thermodynamic activation functions of the dissolution process were also calculated as a function of each inhibitor concentration. All the results obtained from the methods employed are in reasonable agreement.
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a newly synthesized glycine derivative to control uniform and pitting corrosion processes of al induced by scn anions chemical electrochemical and morphological studies
Corrosion Science, 2010Co-Authors: Mohammed A AminAbstract:Abstract A newly synthesized glycine derivative (termed GlyD), 2-(4-(dimethylamino)benzylamino)acetic acid hydrochloride, was used to inhibit uniform and pitting corrosion processes of Al in 0.50 M KSCN solutions (pH 6.8) at 25 °C. For uniform corrosion inhibition study, Tafel Extrapolation, linear polarization resistance and impedance methods were used, complemented with SEM examinations. An independent method of chemical analysis, namely ICP-AES (inductively coupled plasma atomic emission spectrometry) was also used to test validity of corrosion rate measured by Tafel Extrapolation method. GlyD inhibited uniform corrosion, even at low concentrations, reaching a value of inhibition efficiency up to 97% at a concentration of 5 × 10 −3 M. Results obtained from the different corrosion evaluation techniques were in good agreement. This new synthesized glycine derivative was also used to control pit nucleation and growth on the pitted Al surface based on cyclic polarization, potentiostatic and galvanostatic measurements. The pitting potential ( E pit ) and the repassivation potential ( E rp ) increased by the addition of GlyD. Thus GlyD suppressed pit nucleation and propagation. Nucleation of pit was found to take place after an incubation time ( t i ). The rate of pit nucleation and growth decreased with increase in inhibitor concentration. Morphology of pitting was also studied as a function of the applied anodic potential and solution temperature. Cross-sectional view of pitted surface revealed the formation of large distorted hemispherical and narrow deep pits. GlyD was much better than Gly in controlling uniform and pitting corrosion processes of Al in these solutions.
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a study of the inhibition of iron corrosion in hcl solutions by some amino acids
Corrosion Science, 2010Co-Authors: K F Khaled, Mohammed A Amin, Q Mohsen, H A AridaAbstract:Abstract The performance of three selected amino acids, namely alanine (Ala), cysteine (Cys) and S-methyl cysteine (S-MCys) as safe corrosion inhibitors for iron in aerated stagnant 1.0 M HCl solutions was evaluated by Tafel polarization and impedance measurements. Results indicate that Ala acts mainly as a cathodic inhibitor, while Cys and S-MCys function as mixed-type inhibitors. Cys, which contains a mercapto group in its molecular structure, was the most effective among the inhibitors tested, while Ala was less effective than S-MCys. The low inhibition efficiency recorded for S-MCys compared with that of Cys was attributed to steric effects caused by the substituent methyl on the mercapto group. Electrochemical frequency modulation (EFM) technique and inductively coupled plasma atomic emission spectrometry (ICP-AES), were also applied to make accurate determination of corrosion rates. Validation of the Tafel Extrapolation method for measuring corrosion rates was tested. Rates of corrosion rates (in μm y −1 ) obtained from Tafel Extrapolation method are in good agreement with those measured using EFM and ICP methods. Some theoretical studies, including molecular dynamics (MD) and density functional theory (DFT), were also employed to establish the correlation between the structure (molecular and electronic) of the three tested inhibitors and the inhibition efficiency. Adsorption via hydrogen bonding was discussed here based on some theoretical studies. Experimental and theoretical results were in good agreement.
Andrej Atrens - One of the best experts on this subject based on the ideXlab platform.
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measurement of the corrosion rate of magnesium alloys using Tafel Extrapolation
Corrosion Science, 2010Co-Authors: Zhiming Shi, Ming Liu, Andrej AtrensAbstract:The hypothesis that the corrosion of Mg alloys can be adequately estimated using Tafel Extrapolation of the polarisation curve is termed herein the electrochemical measurement hypothesis for Mg. In principle, such a hypothesis can be disproved by a single valid counter example. The critical review of Mg corrosion by Song and Atrens in 2003 indicated that, for Mg alloys, Tafel Extrapolation had not estimated the corrosion rate reliably. This paper examines the recent literature to further examine the electrochemical measurement hypothesis for Mg. The literature shows that, for Mg alloys, corrosion rates evaluated by Tafel Extrapolation from polarisation curves have not agreed with corrosion rates evaluated from weight loss and hydrogen evolution. Typical deviations have been ∼50–90%. These were much larger than the precision of the measurement methods and indicate a need for careful examination of the use of Tafel Extrapolation for Mg. For research that nevertheless does intend to use Tafel Extrapolation to elucidate corrosion of Mg associated with service, it is strongly recommended that these measurements be complemented by the use of at least two of the three other simple measurement methods: (i) weight loss rate, (ii) hydrogen evolution rate, and (iii) rate of Mg2+ leaving the metal surface. There is much better insight for little additional effort.
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an exploratory study of the corrosion of mg alloys during interrupted salt spray testing
Corrosion Science, 2009Co-Authors: Mingchun Zhao, Patrik Schmutz, Samuel Brunner, Guangling Song, Andrej AtrensAbstract:Abstract A first systematic investigation was carried out to understand the corrosion of common Mg alloys (Pure Mg, AZ31, AZ91, AM30, AM60, ZE41) exposed to interrupted salt spray. The corrosion rates were also evaluated for these alloys immersed in 3 wt.% NaCl by measuring hydrogen evolution and an attempt was made to estimate the corrosion rate using Tafel Extrapolation of the cathodic branch of the polarisation curve. The corrosion of these alloys immersed in the 3 wt.% NaCl solution was controlled by the following factors: (i) the composition of the alpha-Mg matrix, (ii) the volume fraction of second phase and (iii) the electrochemical properties of the second phase. The Mg(OH) 2 surface film on Mg alloys is probably formed by a precipitation reaction when the Mg 2+ ion concentration at the corroding surface exceeds the solubility limit. Improvements are suggested to the interrupted salt spray testing; the ideal test cycle would be a salt spray of duration X min followed by a drying period of (120– X ) min. Appropriate apparatus changes are suggested to achieve 20% RH rapidly within several minutes after the end of the salt spray and to maintain the RH at this level during the non-spray part of the cycle. The electrochemical measurements of the corrosion rate, based on the “corrosion current” at the free corrosion potential, did not agree with direct measurements evaluated from the evolved hydrogen, in agreement with other observations for Mg.
K F Khaled - One of the best experts on this subject based on the ideXlab platform.
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a study of the inhibition of iron corrosion in hcl solutions by some amino acids
Corrosion Science, 2010Co-Authors: K F Khaled, Mohammed A Amin, Q Mohsen, H A AridaAbstract:Abstract The performance of three selected amino acids, namely alanine (Ala), cysteine (Cys) and S-methyl cysteine (S-MCys) as safe corrosion inhibitors for iron in aerated stagnant 1.0 M HCl solutions was evaluated by Tafel polarization and impedance measurements. Results indicate that Ala acts mainly as a cathodic inhibitor, while Cys and S-MCys function as mixed-type inhibitors. Cys, which contains a mercapto group in its molecular structure, was the most effective among the inhibitors tested, while Ala was less effective than S-MCys. The low inhibition efficiency recorded for S-MCys compared with that of Cys was attributed to steric effects caused by the substituent methyl on the mercapto group. Electrochemical frequency modulation (EFM) technique and inductively coupled plasma atomic emission spectrometry (ICP-AES), were also applied to make accurate determination of corrosion rates. Validation of the Tafel Extrapolation method for measuring corrosion rates was tested. Rates of corrosion rates (in μm y −1 ) obtained from Tafel Extrapolation method are in good agreement with those measured using EFM and ICP methods. Some theoretical studies, including molecular dynamics (MD) and density functional theory (DFT), were also employed to establish the correlation between the structure (molecular and electronic) of the three tested inhibitors and the inhibition efficiency. Adsorption via hydrogen bonding was discussed here based on some theoretical studies. Experimental and theoretical results were in good agreement.
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testing validity of the Tafel Extrapolation method for monitoring corrosion of cold rolled steel in hcl solutions experimental and theoretical studies
Corrosion Science, 2010Co-Authors: Mohammed A Amin, K F Khaled, Sahar A FadlallahAbstract:Abstract The protection influence of glycine (Gly) and a one of its derivatives, namely 2-(bis(2-aminoethyl)amino) acetic acid, designated here as GlyD; where GlyD stands for “glycine derivative”, against cold rolled steel (CRS) corrosion was studied in aerated stagnant 1.0 M HCl solutions at 25 °C. Measurements were conducted under various experimental conditions using Tafel polarization, linear polarization and impedance techniques. These studies have shown that Gly and GlyD are very good “green”, mixed-type inhibitors. GlyD is more effective than Gly itself in inhibiting the acid corrosion of CRS. Electrochemical frequency modulation (EFM) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) method of analysis are also presented here for monitoring corrosion. Corrosion rates obtained from both EFM and ICP-AES methods are comparable with those recorded using Tafel Extrapolation method, confirming validation of corrosion rates measured by the latter. Adsorption via H-bond is discussed here, based on the presence of oxide film on the electrode surface as well as the number of NH linkages in the inhibitor molecule. Quantum chemical method was also employed to explore the relationship between the inhibitor molecular properties and its protection efficiency. The density function theory (DFT) is used to study the structural properties of Gly and GlyD in aqueous phase in an attempt to understand their inhibition mechanism. The protection efficiencies of these compounds showed a certain relationship to highest occupied molecular orbital (HOMO) energy, Mulliken atomic charges and Fukui indices.
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corrosion monitoring of mild steel in sulphuric acid solutions in presence of some thiazole derivatives molecular dynamics chemical and electrochemical studies
Corrosion Science, 2009Co-Authors: K F Khaled, Mohammed A AminAbstract:Abstract The physical behavior of three selected thiazole derivatives, namely 2-Amino-4-( p -tolyl)thiazole (APT), 2-Methoxy-1,3-thiazole (MTT) and Thiazole-4-carboxaldehyde (TCA) at iron (1 1 0) surface dissolved in aqueous solution were studied via molecular dynamics (MD) simulations. From the calculated binding energies, APT showed preferred adsorption on the steel surface among the three tested thiazole derivatives. The inhibition performance of the three thiazoles on the corrosion of mild steel in 0.5 M H 2 SO 4 solutions was investigated at 25 °C. Measurements were conducted under various experimental conditions using weight loss, Tafel polarization and electrochemical impedance spectroscopy. Electrochemical frequency modulation (EFM) technique was also employed here to make accurate determination of the corrosion rates and test validation of the Tafel Extrapolation method for measuring corrosion rates. Polarization curves showed that the three thiazole derivatives were of mixed-type inhibitors for mild steel corrosion in 0.5 M H 2 SO 4 solution. EFM results were in agreement with other traditional chemical and electrochemical techniques used in corrosion rate measurements. Chemical and electrochemical measurements are consistent with computational study that APT is the most effective inhibitor among the tested thiazoles.
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evaluation of electrochemical frequency modulation as a new technique for monitoring corrosion and corrosion inhibition of carbon steel in perchloric acid using hydrazine carbodithioic acid derivatives
Journal of Applied Electrochemistry, 2009Co-Authors: K F KhaledAbstract:Electrochemical frequency modulation, EFM is a new technique for corrosion rate measurements. With the EFM technique, the corrosion rate and corrosion kinetic parameters can be obtained instantaneously without prior knowledge of Tafel slopes, which makes this method an ideal technique for application as a corrosion monitoring tool. Results obtained with the EFM technique were shown to be in agreement with chemical (weight loss) and electrochemical methods (Tafel Extrapolation and electrochemical impedance spectroscopy, EIS) for corrosion rate measurements. New synthesized hydrazine carbodithioic acid derivatives namely, N′-furan-2-yl-methylene-hydrazine carbodithioic acid (A), N′-(4-dimethylamino-benzylidene)-hydrazine carbodithioic acid (B) and N′-(3-nitro-benzylidene)-hydrazine carbodithioic acid (C) were examined as corrosion inhibitors for carbon steel in 1 M perchloric acid solution. The results obtained from both chemical and electrochemical measurements show that these compounds suppressed both anodic and cathodic processes of carbon steel corrosion in 1 M HClO4 by adsorption on the electrode surface. The adsorption mode follows the Langmuir adsorption isotherm. The efficiency of the inhibitors increases in the order C > B > A.
Kevin P. Plucknett - One of the best experts on this subject based on the ideXlab platform.
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the influence of ni3al binder content on the aqueous corrosion response of tic and ti c n cermets
International Journal of Refractory Metals & Hard Materials, 2017Co-Authors: Zhila Memarrashidi, Kevin P. PlucknettAbstract:Abstract In the current work the corrosion mechanisms of Ti(C,N) based cermets are analysed in a 3.5 wt.% NaCl aqueous solution. The effects of varying the Ni 3 Al intermetallic binder content are assessed, with either 20 or 30 vol.% binder used. The assessment of corrosion involved a variety of electrochemical measurements, including open circuit potential, along with anodic and cathodic potentiodynamic polarisation. Both the corrosion potential and current density were determined from Tafel Extrapolation, which allowed an estimation of the cermet corrosion rates. It is demonstrated that the primary corrosion mechanism for these cermets involves dissolution of the intermetallic phase during oxidation attack, and thus this response increases with the amount of binder in the cermet. It was also observed that addition of N to the Ti(C,N) ceramic phase is beneficial to the corrosion characteristic the cermets, due to significant refinement of the grain size of the hard phase.
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the effects of metal binder content and carbide grain size on the aqueous corrosion behaviour of tic 316l stainless steel cermets
International Journal of Refractory Metals & Hard Materials, 2014Co-Authors: Chukwuma C Onuoha, Georges J. Kipouros, Zoheir Farhat, Kevin P. PlucknettAbstract:Abstract The room temperature electrochemical response of TiC-based cermets, with 10 to 30 vol.% 316L stainless steel binder and either fine- or coarse-grained TiC, has been investigated in an aqueous 3.5 wt.% NaCl solution. The assessment methods included Tafel Extrapolation, in combination with potentiodynamic and potentiostatic polarisation. Corroded samples were characterised using SEM, with post-corrosion solutions analysed using ICP-OES. The highest corrosion resistance was achieved at the lowest binder contents, while those with a more coarse-grained structure generally showed superior resistance, due to a reduced TiC–316L interfacial area. Preferential dissolution of the steel binder was observed, leaving the TiC essentially unaffected.
A D Davydov - One of the best experts on this subject based on the ideXlab platform.
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determination of corrosion rate of molybdenum rhenium and their alloys in sodium chloride solution by the method of Tafel Extrapolation
Russian Journal of Electrochemistry, 2014Co-Authors: V S Shaldaev, A N Malofeeva, A D DavydovAbstract:Based on the measured voltammograms, the corrosion potentials and corrosion current densities of Mo, Re, and several their alloys in the NaCl solutions were determined by the method of Tafel Extrapolation. The dependences of Ecorr and icorr on the alloy composition, including the corresponding values for the metals (alloy components), were plotted. The obtained values of icorr and the corrosion rates in the linear units were compared with the literature data.
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electrochemical behavior and the rate of general corrosion of nial intermetallic compound in the unbuffered sodium chloride solutions
Corrosion Science, 2011Co-Authors: K V Rybalka, L A Beketaeva, N G Bukhanko, A D DavydovAbstract:Highly reproducible Tafel anodic and cathodic plots were obtained on NiAl intermetallic compound in the neutral and nearly neutral unbuffered NaCl solutions. The corrosion potentials and corrosion current densities were determined by the Tafel Extrapolation technique at various pH values and concentrations of NaCl. The corrosion current density and Tafel slopes were determined by fitting the equation for the corrosion current density, which involves both anodic and cathodic reactions, to the experimental anodic and cathodic polarization curves in the pre-Tafel region of polarization curves. The results obtained by two methods are in good agreement.
