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Salaheddine Stiriba - One of the best experts on this subject based on the ideXlab platform.

  • towards a deeper understanding of the inhibition mechanism of a new 1 2 3 triazole derivative for mild steel Corrosion in the hydrochloric acid solution using coupled experimental and theoretical methods
    Materials Chemistry and Physics, 2020
    Co-Authors: Aziz Boutouil, My Rachid Laamari, Ilham Elazhary, Lahoucine Bahsis, Hafid Anane, Salaheddine Stiriba
    Abstract:

    Abstract The Corrosion inhibition effect of a new synthesized heterocycle 1,2,3-triazole, namely(1-p-tolyl-1H-1,2,3-triazol-4-yl) methanol (TTM) was studied in 1 M hydrochloric acid solution by using both experimental and theoretical techniques. The inhibitory action of the TTM was investigated by potentiodynamic polarization (PDP) at various temperatures (298–333 K). PDP experiments revealed that the TTM behaved as mixed type inhibitor by decreasing both anodic and Cathodic Corrosion densities. Electrochemical impedance spectroscopy (EIS) measurements confirmed that the studied inhibitor can suppress mild steel Corrosion effectively in acidic solution with an inhibition efficiency of 90% after 60 min of immersion. The adsorption of the TTM compound on the mild steel surface was found to follow the Langmuir and El-Awady thermodynamic-kinetic models. The changes in contact angles from 80° to 102° identified the generation of an adsorbed protective layer which is confirmed by SEM/EDX investigation and FT-IR spectroscopy. Additional insights on the most reactive areas in terms of donor/acceptor interactions were derived using DFT based quantum chemical calculations for neutral as well as protonated forms of TTM. Molecular dynamics simulations (MD) have been adopted to shed light on the mechanism of molecular adsorption. The interactions between TTM and Fe-atoms were characterized with the aid of reduced density gradient (RDG); vdW interaction seems to be the dominative regime of TTM- Fe atoms in the hydrochloric acid solution. Under dynamic mode, TTM protects the mild steel against Corrosion by constraining the diffusion of corrosive ions (H2O, H3O+, Cl−) present on its surface. Electron localization function (ELF), Fractional free volume (FFV) are used as powerful tool to provide a better theoretical scenario for understanding the mode of adsorption on the surface of Mild steel (MS).

Gary P. Halada - One of the best experts on this subject based on the ideXlab platform.

  • interactions of the components of chromate conversion coating with the constituents of aluminum alloy aa2024 t3
    Journal of The Electrochemical Society, 2004
    Co-Authors: Devicharan Chidambaram, C R Clayton, Gary P. Halada
    Abstract:

    Electrochemical techniques were employed to study the nature of individual interactions between the chemicals constituting a widely used commercial chromate conversion-coating treatment and the main constituents of AA2024-T3 alloy, namely, Al (99.999%), Al 2 Cu, Al-Al 2 Cu galvanic couple, and AA2024-T3 alloy. The samples were pretreated using chromate, ferricyanide, fluoride, tetrafluoroborate, and hexafluorozirconate, prior to electrochemical Corrosion tests. The results were compared with untreated (control) samples. For the first time, the chemical interaction of aluminum with hexafluorozirconate has been studied. Maximum activation was observed in the case of hexafluorozirconate pretreatment, which also decreased the interfacial tension and increased surface wetting. The electrochemistry of the control and pretreated (except for hexafluorozirconate pretreatment) AA2024-T3 and Al 2 Cu were found to be similar. The Cathodic electron transfer reaction rate for oxygen reduction was found to be enhanced by the presence of copper in the systems. The enhancement was proportional to the copper content. The Cathodic reaction on all systems was inhibited by chromate. Aluminum was observed to undergo Cathodic Corrosion, leading to an enrichment of the surface copper content and subsequent enhancement of the Cathodic electron transfer reaction.

  • interactions of the components of chromate conversion coating with the constituents of aluminum alloy aa2024 t3
    Journal of The Electrochemical Society, 2004
    Co-Authors: Devicharan Chidambaram, C R Clayton, Gary P. Halada
    Abstract:

    Electrochemical techniques were employed to study the nature of individual interactions between the chemicals constituting a widely used commercial chromate conversion-coating treatment and the main constituents of AA2024-T3 alloy, namely, Al (99.999%), Al 2 Cu, Al-Al 2 Cu galvanic couple, and AA2024-T3 alloy. The samples were pretreated using chromate, ferricyanide, fluoride, tetrafluoroborate, and hexafluorozirconate, prior to electrochemical Corrosion tests. The results were compared with untreated (control) samples. For the first time, the chemical interaction of aluminum with hexafluorozirconate has been studied. Maximum activation was observed in the case of hexafluorozirconate pretreatment, which also decreased the interfacial tension and increased surface wetting. The electrochemistry of the control and pretreated (except for hexafluorozirconate pretreatment) AA2024-T3 and Al 2 Cu were found to be similar. The Cathodic electron transfer reaction rate for oxygen reduction was found to be enhanced by the presence of copper in the systems. The enhancement was proportional to the copper content. The Cathodic reaction on all systems was inhibited by chromate. Aluminum was observed to undergo Cathodic Corrosion, leading to an enrichment of the surface copper content and subsequent enhancement of the Cathodic electron transfer reaction.

G Kyriacou - One of the best experts on this subject based on the ideXlab platform.

  • electrochemical reduction of nitrate on bismuth cathodes
    Journal of Electroanalytical Chemistry, 2009
    Co-Authors: M Dortsiou, G Kyriacou
    Abstract:

    Abstract The electrochemical reduction of nitrate was studied on bismuth cathodes in a 0.4 M NaHCO3/0.4 M Na2CO3 solution containing 0.05 M NaNO3. The main product of the electrolysis was nitrogen having selectivity (%S) between 58% and 65%. The other products were nitrous oxide (7–22%), ammonia (3.8–19%) and nitrite (1.8–2.6%). The total Faradaic Efficiency (%FE) was ranged from 80% at −1.8 to 20% at −2.6 V vs. Ag/AgCl. The reduction of nitrate takes place through two paths; the first is electrochemical and the second one is autocatalytic, which involves an intermediate having an oxidation number lower than +2. The rate of the autocatalytic path at −1.8 V vs. Ag/AgCl was up to 48 times higher than that of the electrochemical one. The bismuth cathode undergoes slow Cathodic Corrosion during the electrolysis the rate of which increases with the increase of the negative potential. Bismuth is a promising cathode for the treatment of wastewaters containing nitrate, such as the low level nuclear wastes, since both the rate of the reduction and the selectivity to nitrogen are high.

  • efficient electrochemical reduction of nitrate to nitrogen on tin cathode at very high Cathodic potentials
    Electrochimica Acta, 2006
    Co-Authors: Ioannis Katsounaros, Dimitris Ipsakis, C Polatides, G Kyriacou
    Abstract:

    Abstract The electrochemical reduction of nitrate on tin cathode at very high Cathodic potentials was studied in 0.1 M K 2 SO 4 , 0.05 M KNO 3 electrolyte. A high rate of nitrate reduction (0.206 mmol min −1  cm −2 ) and a high selectivity (% S ) of nitrogen (92%) was obtained at −2.9 V versus Ag/AgCl. The main by-products were ammonia (8%) and nitrite ( 2 O and traces of NO were also detected. As the Cathodic potential increases, the % S of nitrogen increases, while that of ammonia displays a maximum at −2.2 V. The % S of nitrite decreases from 65% at −1.8 V to The reduction follows first order kinetics for both nitrate and nitrite at more Cathodic potentials than −2.4 V, while at less negative potentials the kinetics is more complicated. The %Faradaic efficiency (%FE) of the reduction at −2.9 V was about 60% initially and decreased to 22% at 40 min. A Cathodic Corrosion of tin was observed, which was more intensive in the absence of nitrate. At potentials more negative than −2.4 V, small amounts of tin hydride were detected.

Devicharan Chidambaram - One of the best experts on this subject based on the ideXlab platform.

  • interactions of the components of chromate conversion coating with the constituents of aluminum alloy aa2024 t3
    Journal of The Electrochemical Society, 2004
    Co-Authors: Devicharan Chidambaram, C R Clayton, Gary P. Halada
    Abstract:

    Electrochemical techniques were employed to study the nature of individual interactions between the chemicals constituting a widely used commercial chromate conversion-coating treatment and the main constituents of AA2024-T3 alloy, namely, Al (99.999%), Al 2 Cu, Al-Al 2 Cu galvanic couple, and AA2024-T3 alloy. The samples were pretreated using chromate, ferricyanide, fluoride, tetrafluoroborate, and hexafluorozirconate, prior to electrochemical Corrosion tests. The results were compared with untreated (control) samples. For the first time, the chemical interaction of aluminum with hexafluorozirconate has been studied. Maximum activation was observed in the case of hexafluorozirconate pretreatment, which also decreased the interfacial tension and increased surface wetting. The electrochemistry of the control and pretreated (except for hexafluorozirconate pretreatment) AA2024-T3 and Al 2 Cu were found to be similar. The Cathodic electron transfer reaction rate for oxygen reduction was found to be enhanced by the presence of copper in the systems. The enhancement was proportional to the copper content. The Cathodic reaction on all systems was inhibited by chromate. Aluminum was observed to undergo Cathodic Corrosion, leading to an enrichment of the surface copper content and subsequent enhancement of the Cathodic electron transfer reaction.

  • interactions of the components of chromate conversion coating with the constituents of aluminum alloy aa2024 t3
    Journal of The Electrochemical Society, 2004
    Co-Authors: Devicharan Chidambaram, C R Clayton, Gary P. Halada
    Abstract:

    Electrochemical techniques were employed to study the nature of individual interactions between the chemicals constituting a widely used commercial chromate conversion-coating treatment and the main constituents of AA2024-T3 alloy, namely, Al (99.999%), Al 2 Cu, Al-Al 2 Cu galvanic couple, and AA2024-T3 alloy. The samples were pretreated using chromate, ferricyanide, fluoride, tetrafluoroborate, and hexafluorozirconate, prior to electrochemical Corrosion tests. The results were compared with untreated (control) samples. For the first time, the chemical interaction of aluminum with hexafluorozirconate has been studied. Maximum activation was observed in the case of hexafluorozirconate pretreatment, which also decreased the interfacial tension and increased surface wetting. The electrochemistry of the control and pretreated (except for hexafluorozirconate pretreatment) AA2024-T3 and Al 2 Cu were found to be similar. The Cathodic electron transfer reaction rate for oxygen reduction was found to be enhanced by the presence of copper in the systems. The enhancement was proportional to the copper content. The Cathodic reaction on all systems was inhibited by chromate. Aluminum was observed to undergo Cathodic Corrosion, leading to an enrichment of the surface copper content and subsequent enhancement of the Cathodic electron transfer reaction.

Baorong Hou - One of the best experts on this subject based on the ideXlab platform.

  • the effect of some triazole derivatives as inhibitors for the Corrosion of mild steel in 1 m hydrochloric acid
    Applied Surface Science, 2009
    Co-Authors: Shengtao Zhang, Zhihua Tao, Baorong Hou
    Abstract:

    Corrosion inhibition by some new triazole derivatives on mild steel in 1 M hydrochloric acid solutions has been investigated by weight loss test, electrochemical measurement, scanning electronic microscope analysis and quantum chemical calculations. The results indicate that these compounds act as mixed-type inhibitors retarding the anodic and Cathodic Corrosion reactions and do not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The studied compounds following the Langmuir adsorption isotherm, and the thermodynamic parameters were determined and discussed. The effect of molecular structure on the inhibition efficiency has been investigated by ab initio quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, energy gap (LUMO-HOMO), dipole moment and molecular orbital densities were calculated. (C) 2009 Published by Elsevier B.V.