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129 results on '"Sfaira, M."'

30. Investigation of the Effect of MoO42− and Co2+ up on Electroless Ni–Mo–P and Ni–Co–P Alloys in Acidic Solution Using Tyrosine as Stabilizer: Characterization and Electrochemical Study.

Author

EL Haloui, A., Driouch, M., EL Assiri, EL H., Sfaira, M., Ebn Touhami, M., and Zarrouk, A.

Subjects
ELECTROLESS deposition, PLATING baths, TYROSINE, ION plating, CARBON dioxide, SURFACE coatings
Abstract

The deposition rate, composition, morphology, and structure of electroless deposits Ni–Mo–P and Ni–Co–P plated at different concentrations of MoO 4 2 - and Co 2 + from acidic tyrosine baths were conducted in this study. Electrochemical study of electroless Ni–Co–P coating was investigated. The deposition rate and the composition of Ni–Mo–P and Ni–Co–P coatings were determined using gravimetric and EDX method which depends on the corresponding ions concentration in the plating bath. The MoO 4 2 - ion played rather an inhibitor role of electroless Ni–Mo–P coating even at low concentration in the plating bath. SEM was used to analyze the morphology of electroless alloys, whereas XRD was used to investigate the structure evolution. The Ni–P, Ni–Mo–P and Ni–Co–P deposits were characterized by distinct morphology depending on P, Mo and Co content in the coatings, whereas, the structure of each alloy depended only on P and Co contents in Ni–Co–P coating. Either MoO 4 2 - or Co 2 + ions concentration had different effects on the deposition rate, the structure and the quality of electroless Ni–Mo–P and Ni–Co–P deposits. [ABSTRACT FROM AUTHOR]

Published
2022
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35. DFT Theoretical Study of 5-(4-R-Phenyl)-1H-tetrazole (R = H; OCH3; CH3; Cl) as Corrosion Inhibitors for Mild Steel in Hydrochloric Acid.

Author

El Hassani, A. A., El Adnani, Z., Benjelloun, A. T., Sfaira, M., Benzakour, M., Mcharfi, M., Hammouti, B., and Emran, K. M.

Abstract

Quantum chemical study, based on DFT methods at B3LYP/6-31G (d, p) level of theory, of four tetrazole compounds, denoted Ph-T, Me-Ph-T, MeO-Ph-T, Cl-Ph-T and reported as corrosion inhibitors in acidic medium, has been investigated in an attempt to find relationships between their molecular electronic properties and their corresponding experimental corrosion inhibition efficiencies. The global reactivity descriptors, such as the frontier molecular orbital energies (EHOMO and ELUMO), energy gap ∆E, electronegativity χ, absolute hardness η and softens σ, fraction of electrons transferred ∆N as well as local selectivity parameters such as Natural Atomic Populations and Fukui indices were also calculated and discussed. The calculations were undertaken in both gaseous and aqueous states for a better approach of the experimental conditions. The results showed that Cl-Ph-T presented the lowest ELUMO and the highest χ indicating its high electron acceptor ability, which can explain its good corrosion inhibition efficiency when compared to the three-other studied tetrazole derivatives. [ABSTRACT FROM AUTHOR]

Published
2020
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38. DFT-based QSAR Study of Substituted Pyridine - Pyrazole Derivatives as Corrosion Inhibitor s in Molar Hydrochloric Acid

Author

El Adnani, Z., Benjelloun, A.T., Benzakour, M., Mcharfi, M., Sfaira, M., Saffaj, T., Ebn Touhami, M., Hammouti, B., Al - Deyab, S.S., and Ebenso, Eno E.

Subjects
Pyridine - pyrazole, QSAR, PCM, Corrosion inhibition, DFT
Abstract

Quantum chemical calculations, based on DFT methods at B3LYP/6-31G** level of theory, were performed, by means of the G03 set of programs, on four pyridine -pyrazole compounds. The objective of this work was to attempt to find relationships between the intrinsic electronic properties and inhibiting efficiencies of two pyridine-pyrazole derivatives, denoted H-PP and Br-PP, which have been previously studied experimentally as mild steel corrosion inhibitors in acidic medium. Based on these results, the Quantitative Structure–Activity Relationships (QSAR) studies allowed us to calculate the inhibitive efficiencies for the former and for two other pyridine-pyrazole derivatives, Cl-PP and Me -PP, of which the experimental study, was not yet made. The structural electronic properties of the whole pyridine-pyrazole molecules were investigated by means of number of global and local theoretical reactivity descriptors. The results showed that the electronic effect of the substituent at the meta of the pyridine ring markedly influenced the performance of the studied inhibitors. The QSAR’s quadratic model results, representing the best fitting, showed that the Cl -PP and Me-PP will probably have the same corrosion inhibitory performance as Br -PP and H-PP, respectively especially at higher concentrations . http://www.electrochemsci.org/papers/vol9/90904732.pdf http://www.electrochemsci.org/list14.htm#issue9

Published
2014

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