M. BERARMA Khedidja

MCA

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Department

Departement of Chemistry

Research Interests

Matériaux

Contact Info

University of M'Sila, Algeria

Email : khadidja.berarma@univ-msila.dz

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Recent Publications

2024-02-01

An ab-initio study on the physical properties of double perovskite Cs2AgXBr6 (X=S, Te, Se)

Cs2AgXBr6 (X = S, Se, and Te) double perovskite structural, electronic, and optical properties were investigated using the density functional theory (DFT) method combined with various correlation potentials such as TB-mBJ, LDA, PBE, WC, and hybrid functionals (YS-PBE0). The calculated structural and elastic properties revealed that the Cs2AgXBr6 compounds are elastically stable, ductile, anisotropic, and ionically bonded. Both Poisson ratio and Pugh ratio confirm that Cs2AgXBr6 (X = S, Te, Se) compounds are ductile. The calculated density of States (DOS) and the electronic band structures of the investigated compounds display zero band gaps for these compounds. Therefore, the calculated electronic properties of these compounds indicate their metallic nature. The calculated optical transmittance shows the transparent behaviors of studied compounds.
Citation

M. BERARMA Khedidja, (2024-02-01), "An ab-initio study on the physical properties of double perovskite Cs2AgXBr6 (X=S, Te, Se)", [national] Materials Today Communications , Elsevier

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2024-01-10

FIRST PRINCIPLE STUDY OF TRUCTURAL, ELECTRONIC AND THERMOELECTRIC PROPERTIES OF THE DOUBLEE HALF- HEUSLER ALLOYS (Hf2FeNiSb2 AND Hf2FePdSb2)

Renewable energy is energy from sources that nature continually renews. These energies are called “clean” or “green” because their exploitation generates very little waste and polluting emissions, unlike fossil fuels. Among these different energy sources, thermoelectricity is currently emerging as a promising alternative energy source for the future. Thermoelectric materials are compounds capable of converting a temperature gradient into a difference in electrical potential, this is the Seebeck effect, which allows the generation of electricity. In the current energy context where heat loss in human activities industry, automobile sector, etc., is responsible for considerable energy loss, the development of thermoelectric materials appears to be an interesting solution. In the current work, we were interested in double half-Heusler alloys for Hf2FeNiSb2 and Hf2FePdSb2 compounds based on ab-initio calculations carried out with an electronic structure method, in particular the full potential linear augmented plane wave (FP-LAPW) method., within the density functional theory framework (DFT). Additionally, DFT calculations were combined with Boltzmann transport theory to estimate the thermoelectric properties depending on temperature and their changes in terms of relative chemical potential, such as the thermal and electrical conductivity, Seebeck coefficient and figure of merit (ZT).These materials also exhibit a wide range of UV absorption, which makes them suitable for optoelectronic and photovoltaic applications. Also, the calculated thermoelectric properties of the studied compounds, indicates their possible use in thermoelectric device applications.

Keywords: Renewable energy, Thermoelectric materials, Electrical and Thermal Conductivity Coefficients, absorption coefficient, DFT.
Citation

M. BERARMA Khedidja, (2024-01-10), "FIRST PRINCIPLE STUDY OF TRUCTURAL, ELECTRONIC AND THERMOELECTRIC PROPERTIES OF THE DOUBLEE HALF- HEUSLER ALLOYS (Hf2FeNiSb2 AND Hf2FePdSb2)", [international] The International Conference on Materials Chemistry and Sustainable Development (CM2D’23) , UFAS1 Setif

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2023-12-30

Exploring the physical properties of cubic CsGeBr3-nIn (n= 0, 1, 2, 3) compounds: Ab initio calculations of perovskites prospective for the application in solar cells

A B S T R A C T
The cubic perovskites CsGeBr3-nIn (n = 0, 1, 2, 3) were investigated using the density functional theory (DFT) for their structural, electronic, and optical properties. The present DFT calculations are carried out using three models for exchange-correlation potential, namely PBE, mBJ, and YS-PBE0. The bandgap decreases in the above
sequence of compounds except CsGeBrI2, which reveals the smallest bandgap. The mBJ approximation has a larger bandgap than the PBE and smaller than the YS-PBE0. Results of calculations within the YS-PBE0 approach for CsGeBr3 and CsGeI3 agree well with QSGW + SO results. The CsGeBr3-nIn compounds are direct bandgap
semiconductors and CBM and VBM are positioned at the R point and determined mainly by Ge s-states and Br(I) p-states, respectively. Analysis of optical properties shows that the DFT calculations within the PBE model consistently produce the highest static dielectric function values, while the YS-PBE0 method gives the smallest values. The curves of optical coefficients shift toward lower energies when decreasing the Br atoms in CsGeBr3- nIn. The studied compounds are semitransparent in the infrared and visible regions and show promising potential for photovoltaic applications, including solar cells.
Citation

M. BERARMA Khedidja, (2023-12-30), "Exploring the physical properties of cubic CsGeBr3-nIn (n= 0, 1, 2, 3) compounds: Ab initio calculations of perovskites prospective for the application in solar cells", [national] Solid State Sciences , Elsevier

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2023-12-11

Computational characterization of structural, optoelectronic and thermoelectric properties of some double half-Heusler alloys X2FeY′Sb2 (X: Hf, Zr ;Y′: Ni, Pd)

A full-potential linear augmented plane wave (FP-LAPW) has been used to study the structural, electronic, and optical properties of double half-Heusler alloys X2FeY′Sb2 with X≡Zr, Hf and Y′≡Pd, Ni. Electronic band structures and densities of states calculations of the four studied double half-Heusler alloys indicate that they are semiconductors with an indirect gap. The optical spectra of dielectric constants, refractive indices, reflectivity, and light absorption are also discussed. In the energy range of 8–14 eV, the calculated optical properties and mainly the absorption spectrum show very high UV absorption. Additionally, DFT calculations were combined with Boltzmann transport theory to estimate the thermoelectric properties, such as the thermal and electrical conductivity, Seebeck coefficient, and figure of merit (ZT), versus the change of temperature and chemical potential. These alloys possess a suitable band gap for diverse optoelectronic applications, encompassing photovoltaics, UV sensors, and solar cells.
Citation

M. BERARMA Khedidja, Said Al Azar;,Anas Y. Al-Reyahi,Ahmad A. Mousa; Ahmad Mufleh, , (2023-12-11), "Computational characterization of structural, optoelectronic and thermoelectric properties of some double half-Heusler alloys X2FeY′Sb2 (X: Hf, Zr ;Y′: Ni, Pd)", [national] Phase Transitions , Taylor & Francis

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2023-12-02

Ab-initio study of the physical properties of Zr2FeNiSb2

In this present work, we performed a first principle calculation which is based on the density functional theory (DFT) on the investigation of some fundamental physical properties for the double half Heusler alloy Zr2FeNiSb2. The calculations were carried by the method of the full-potential linearized augmented plane wave. The exchange-correlation potential is processed by using the LDA and the GGA to calculate the total energy and other physical properties.. Based on the mBJ approximation, the electronic structures of the studied compound Zr2FeNiSb2, can be described as semiconductor, with indirect band gap of 0.605 eV. A study of the optical properties of half double Heusler, such as dielectric function, refractive index, absorption coefficient, reflectivity, and energy loss function, reveals isotropic optical behavior.
Citation

M. BERARMA Khedidja, (2023-12-02), "Ab-initio study of the physical properties of Zr2FeNiSb2", [national] THE 1st  NATIONAL CONFERENCE ON PHYSICS AND IT’S APPLICATIONS BOUSAADA, December 2nd, 2023 , ENS BOUSAADA

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2023-09-01

Roles of Oxygen Vacancies and Excess Electron Localization on Ceria Surfaces: First Principles Study

In this study, we investigate the (111), (110) and (100) surfaces of reduced ceria (CeO2) using density functional theory (DFT) within DFT+U. We examine the process by which oxygen vacancy sites form on CeO2 (111), (110), and (100) surfaces as well as the stability of these sites close to the ceria surface regions. Our calculations demonstrate that electron localizations of the reduced CeO2 on each of these three surface terminations are caused by oxygen vacancies, both surface and subsurface, which results in the emergence of Ce3+ sites. The oxygen vacancy at the surface and subsurface of CeO2 (111) surfaces results in the formation of Ce3+ at the vacancys next-closest neighbor. Ce3+ is formed at the sites closest to the oxygen vacancy sites on CeO2 (100) and CeO2 (110) surfaces. The calculated total density of states (TDOS) of the reduced surfaces displays that the Ce 4 f states are partially occupied and appeared in a new state near the band gap compared to that for the unreduced ceria surfaces. The existence of these new states was found to have a large effect on the nature of ceria. In (111) ceria surface, the material remains semiconductor with a smaller band gap. However, (110) and (100) ceria surfaces become semi-metallic due to the crossing of a new state of the fermi level that converts ceria to become semi- metallic material. Therefore, the conductivity and chemical properties of ceria are expected to be modified by the creation of oxygen vacancy. The reduced ceria expects to catalyze the dissociation of molecules on its surface. The dissociation is assisted by the oxidation of Ce3+ that is generated on reduced ceria surfaces.
Citation

M. BERARMA Khedidja, (2023-09-01), "Roles of Oxygen Vacancies and Excess Electron Localization on Ceria Surfaces: First Principles Study", [national] International Journal of Thin Films Science and Technology , Natural Sciences Publishing (NSP)".

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2023-08-29

First-principles calculations to investigate structural, mechanical, electronic, optical, and thermoelectric properties of novel cubic double Perovskites X2AgBiBr6 (X=Li, Na, K, Rb, Cs) for optoelectronic devices

Structural, elastic, electronic, optical, and thermoelectric properties of cubic double perovskites X2AgBiBr6 (X = Li, Na, K, Rb, Cs) were investigated using the density functional theory (DFT) method. The DFT calculations were carried out with various exchange-correlation potentials, e.g. LDA, GGA-PBE, GGAWC, and hybrid functionals (YS-PBE0). Structural and elastic properties of X2AgBiBr6 demonstrate that these compounds are ionically bonded, elastically stable, ductile, and anisotropic. Calculations show
that the compounds are semiconductors with indirect bandgap at the (X- L) point, with bandgap values of 2.124, 2.222, 2.198, 2.209, and 1.902 eV for X2AgBiBr6 (X = Li, Na, K, Rb, and Cs), respectively. Due to their distinguishing optical characteristics and indirect wide bandgap, these compounds might be utilised as absorber layers in solar cells and other optoelectronic devices. Moreover, thermoelectric properties show that the Figure of Merit (ZT) has values of 0.713, 0.723, 0.721, 0.726, and 0.728 for
X2AgBiBr6 (X = Li, Na, K, Rb, Cs). The Figure of Merit shows a plateau in the temperature range of 500– 900 K, which corresponds to the highest value of ZT. All investigated compounds have holes as the majority of charge carriers. Thermoelectric properties of X2AgBiBr6 compounds reveal that these compounds can be employed in thermoelectric devices.
Citation

M. BERARMA Khedidja, (2023-08-29), "First-principles calculations to investigate structural, mechanical, electronic, optical, and thermoelectric properties of novel cubic double Perovskites X2AgBiBr6 (X=Li, Na, K, Rb, Cs) for optoelectronic devices", [national] Molecular Simulation , Taylor-Francis

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2023-03-12

Study of The Corrosion Inhibition of a Carbon Steel in Sodium Chloride By The Presence of Sodium Acetate

Chemical inhibitors play an important role in corrosion protection strategies. The most effective inhibitors are organic compounds that have π bonds, hetero-atoms (P, S, N, and O) and inorganic compounds, such as chromate, dichromate, nitrite, etc. However, the use of these compounds has a negative effect in the environment. Thus, the development of new corrosion inhibitors of natural source and non-toxic type was considered more important and desirable; it is in this context that this work is presented.
The objective of this work is to test the inhibitory efficiency of sodium acetate compounds against the corrosion of carbon steel in sodium chloride (NaCl) medium. The study was carried out in a chloride medium (NaCl : 1M). The measurements were carried out by electrochemical techniques (measurement of the corrosion potential on abandonment, the linear polarization resistance and the technique of electrochemical impedance spectroscopy). The obtained results clearly show that, the corrosion inhibition process of the steel electrode is better for NaCl electrolyte solutions (1M) with the addition of sodium acetate (10-3M) and with an inhibition rate of 60%.


Keywords :corrosion, inhibitor, carbon steel
Citation

M. BERARMA Khedidja, (2023-03-12), "Study of The Corrosion Inhibition of a Carbon Steel in Sodium Chloride By The Presence of Sodium Acetate", [national] THE 3rdNATIONAL CONFERENCEON APPLIED PHYSICS & CHEMISTRY Laghouat, 12th&13th march 2023 , Université de Laghouat

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2022-09-29

Effet inhibiteur du benzoate de sodium sur la corrosion de l'alliage d'aluminium

Exposé à l’air, l’aluminium se recouvre instantanément d’une fine couche d’alumine transparente, continue, adhérente et protégeant le métal contre l’oxydation. Le film d’oxyde est relativement stable dans les solutions aqueuses. Dans certains environnements, comme en présence d'ions Cl-, l'aluminium et ses alliages sont très sensibles à la corrosion localisée. Par conséquent, l'utilisation d'inhibiteurs de corrosion est l'une des méthodes de protection contre la corrosion les plus efficaces. Les propositions de nouveaux inhibiteurs de corrosion efficaces reposent actuellement sur des tests expérimentaux, qui permettent de savoir si une molécule spécifique est efficace ou non pour un substrat donné dans un milieu donné. Le but de ce travail est de tester le benzoate de sodium comme inhibiteur de corrosion de l'alliage d'aluminium dans un environnement agressif tel que l'eau de mer. L'effet inhibiteur du benzoate de sodium sur la corrosion de l'alliage d'aluminium dans NaCl (3,5%) a été étudié par des méthodes électrochimiques telles que ; les mesures de potentiel en circuit ouvert (ocp), les courbes de polarisation et la spectroscopie d'impédances électrochimiques. Les résultats indiquent une efficacité d'inhibition du benzoate de sodium atteignant environ 96% avec une concentration de 10-2 g/L.
Citation

M. BERARMA Khedidja, (2022-09-29), "Effet inhibiteur du benzoate de sodium sur la corrosion de l'alliage d'aluminium", [national] 1iere Journée Nationale de Chimie (JNCET-2022) , Université Chadeli Bendjedid- ’El Tarf

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2022-09-10

Theoretical study of the electronic and optical properties of SrVO3 Perovskite

Our work aimed to investigate the structural, electrical, and optical characteristics of SrVO3 Perovskite material using first principles calculations based on Density Functional Theory. The band structure and DOS studies revealed that the SrVO3Perovskite compound had metallic properties since we noticed that the Fermi level crosses some energy bands. According to the DOS diagrams, the valence band maximum (VBM) is made up of hybridization of the O-2p and Fe-d orbitals, whereas the conduction band minimum (CBM) is largely made up of the Op orbital. The estimated real and imaginary components of the complex dielectric function were used to determine frequency-dependent linear macroscopic optical coefficients such as absorption coefficient, refractive index, extinction coefficient, reflectivity, and optical conductivity.


Keywords: DFT, Perovskite, Fermi level, band structure, absorption coefficient
Citation

M. BERARMA Khedidja, (2022-09-10), "Theoretical study of the electronic and optical properties of SrVO3 Perovskite", [national] 1st International Conference on InnovativeAcademicStudies , Turquie

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2022-07-27

6) Structural, Elastic, Electronic, Magnetic, and Thermoelectric Characteristics of MgEu 2X4 (X ¼ S, Se) Spinel Compounds: Ab-Initio Calculations.

The structural, elastic, electronic, magnetic, and thermoelectric properties of MgEu2X4 (X ¼ S and Se) spinel compounds are investigated computationally. Calculations are performed using the full-potential linearized augmented plane wave (FP-LAPW) method within the Perdew, Burke, and Ernzerhof generalized gradient approximation (PBE-GGA), GGA þ U, and modified Becke–Johnson (mBJ-GGA) approximations. The band structure and density of states results from the three exchange-correlation approximation methods (mBJ, GGA þ U, and PBE) show that these spinel compounds are fully spin-polarized. Also, they possess a half-metallic character in the spin-down channel with a direct bandgap (Γ–Γ) of about 3.44, 2.712, and 2.472 eV for MgEu2S4 and 2.89, 2.285, and 2.017 eV for MgEu2Se4, respectively. The formation of both compounds is energetically favorable based on the results of the total energy and cohesive energy calculations. Furthermore, the two compounds are chemically and mechanically stable, as concluded from cohesive energy and elastic calculations.
Citation

M. BERARMA Khedidja, (2022-07-27), "6) Structural, Elastic, Electronic, Magnetic, and Thermoelectric Characteristics of MgEu 2X4 (X ¼ S, Se) Spinel Compounds: Ab-Initio Calculations.", [national] Phys. Status Solidi B , Wiley-VCH

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2022-07-20

First-principles study of structural, electronic and optical properties of double half-Heusler alloy :Ta2FeNiSn2

The stability, structural parameters, electronic and optical properties of double half-Heusler alloy Ta2FeNiSn2 are presented by performing ab initio calculations. The density functional theory framework employs the full-potential linearized augmented plane wave (FP-LAPW) method to solve Kohn-Sham equation as implemented in the Wien2k code. The exchange-correlation potential is processed by using the LDA and the GGA-PBE approximations to calculate the total energy and other physical properties. The obtained results showed that alloy Ta2FeNiSn2 possess high cohesive energies, (6.249 eV/atom), these remarkable results support the structural stability for the alloy. Also, the thermodynamic stability of both compounds was confirmed through calculating the formation energy as the obtained results were close to the results obtained in as well as given the Open Quantum Materials Database (OQMD). Electronic characteristics and chemical bonding are illustrated and discussed by computing the electron charge density, DOS, and band structure. The calculated band structures elucidate that the Ta2FeNiSn2 is an indirect semiconductor behavior with (~ 0.5 eV) energy band gap. Also, we have calculated and analyzed the complex dielectric function, absorption coefficient, as well as, reflectivity spectra for Ta2FeNiSn2 compound.

Keywords: double half-Heusler, absorption coefficient, reflectivity, refractive index.
Citation

M. BERARMA Khedidja, (2022-07-20), "First-principles study of structural, electronic and optical properties of double half-Heusler alloy :Ta2FeNiSn2", [international] 3rd International Conference on Applied Engineering and Natural Sciences , Turquie

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2022-06-27

Corrosion Behavior Of Gray Cast Iron Used In Industrial Heating Systems

Corrosion is a major and important problem in industries. In the absence of the appropriate treatment which continues to develop to the point where we are registering the loss of about 5 tons of steel every second in the world. In most industrial sectors, steam is used for different purposes, whether in production processes or to generate heat or electricity. Optimal water treatment is essential to achieve maximum boiler efficiency. Disturbances in boilers caused by corrosion, reduce operational safety and can lead to very serious economic consequences and high maintenance costs. The use of corrosion inhibitors is intended to reduce these costs. The electrochemical behavior of a gray cast iron EN-GJL 250, in a fume boiler feed water at different temperatures was examined by means of the usual stationary electrochemical methods, such as the evolution of the potential for abandonment during time, linear polarization and impedance spectroscopy. This investigation was followed by the study of the influence of the inhibitors used in the HODNA Lait M'sila heating system, namely MAJO 62 and NEXGUARD 22371 . The results reveal that the corrosion inhibition process of gray cast iron is better for corrosive electrolytic solutions with the MAJO 62 inhibitor for which the optimum efficiency is of the order of 68.95% obtained with a concentration of 0.402g/l at a temperature of 20 ° C, while for the NEXGUARD 22371 inhibitor the maximum rate is 23% for a concentration of 0.289g/l at 40 ° C.

Keys word : gray cast iron, inhibitors, corrosion, electrochemical methods
Citation

M. BERARMA Khedidja, (2022-06-27), "Corrosion Behavior Of Gray Cast Iron Used In Industrial Heating Systems", [national] 1st National Conference On Science & Technology MASCARA 27th-28th JUNE 2022 , Mustapha Stambouli University Mascara

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2022-04-08

Opto-electronic, thermodynamic and charge carriers transport properties of Ta2FeNiSn2 and Nb2FeNiSn2 double half-Heusler alloys

A computational research study of the structural, electronic, and optical characteristics of double half-Heusler alloys Ta2FeNiSn2 and Nb2FeNiSn2 is presented by performing ab initio calculations. The density functional theory framework employs the full-potential linearized augmented plane wave method to solve Kohn–Sham equation as implemented in the Wien2k code. The exchange-correlation potential is processed by using the local density approximation and the generalized gradient approximation–Perdew, Burke, and Ernzerhof approximations to calculate the total energy and other physical properties. The obtained results showed that both alloys possess high cohesive energies, where Nb2FeNiSn2 (7.213 eV atom−1) is more consistent than Ta2FeNiSn2 (6.249 eV atom−1), these remarkable results support the structural stability for both alloys. Also, the thermodynamic stability of both compounds was confirmed through calculating the formation energy as the obtained results were close to the results obtained in as well as given the Open Quantum Materials Database. Electronic characteristics and chemical bonding are illustrated and discussed by computing the electron charge density, density of states, and band structure. Both alloys show semiconductor behavior with (∼0.5 eV) indirect energy bandgap. Also, we have calculated and analyzed the complex dielectric function, absorption coefficient, as well as, reflectivity spectra for both compounds. The semi local Boltzmann transport theory has been employed to treat temperature effect on thermoelectric properties of Ta2FeNiSn2 and Nb2FeNiSn2 compounds where the obtained results appears that both compounds have high coefficient at the normal condition, and they also have a good power
factor at the Fermi level, which emphasizes that the thermoelectric efficiency of the two compounds is good and does not require doping. Also, depending on quasi-harmonic model was used for estimating the heat capacity, the lattice thermal conductivity, the thermal expansion and the Debye temperature under the pressure effects.
Citation

M. BERARMA Khedidja, (2022-04-08), "Opto-electronic, thermodynamic and charge carriers transport properties of Ta2FeNiSn2 and Nb2FeNiSn2 double half-Heusler alloys", [national] Semiconductor Science and Technology , IOPscience

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2022-04-03

Electrochemical Characterization of Electrodeposited Ni-titanium Dioxide Deposits on Copper and their Corrosion Study

This work aimed to produce and characterize composite coatings of nickel incorporating TiO2 nanoparticles on a copper substrate. These deposits were obtained from watts
bath. In the study, the cyclic voltammetry technique was employed to provide a better understanding of the cathodic behavior of nickel deposition. The effects of the potential
scanning rate and the effect of cathodic limits on cyclic voltammograms deposition of Ni in Primitive Watts Bath (BWP) were determined. The composite coatings of nickel
incorporating TiO2 nanoparticles were characterized using various electrochemical techniques such as open circuit potential (OCP) and potentiodynamic polarization
measurements, and electrochemical impedance spectroscopic methods. The current density values for the Ni-TiO2 in the case of 5 g/L and 10 g/L of TiO2 determined from the polarization curves recorded in 3.5% NaCl indicate that the corrosion process on nickel incorporating the TiO2 nanoparticle composite surface is slower than on pure
nickel. The TiO2 particles embedded in the electroplated nickel, increase the polarization resistance and decrease the corrosion rates as compared with electrodeposited pure
nickel. Electrochemical impedance spectra obtained at the open-circuit potential (OCP) in 3.5% NaCl showed an increase of polarization resistance with time in all cases.
Keywords: Corrosion, Electrolytic co-deposition, Nickel
Citation

M. BERARMA Khedidja, (2022-04-03), "Electrochemical Characterization of Electrodeposited Ni-titanium Dioxide Deposits on Copper and their Corrosion Study", [national] Nepal Journal of Science and Technology , Nepal Academy of Science and Technology (NAST)

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2021-11-10

Effect of organic compounds on corrosion inhibition of copper in chloride media

Corrosion is a natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, carbonate or sulfide. It is the gradual destruction of materials (usually a metal) by chemical and/or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. The problem of corrosion has assumed considerable importance today, given the greater use of metals and alloys in modern life .Any improvement in protection against corrosion therefore has a significant economic advantage. The scientific approach developed in this work is geared towards understanding the phenomena associated with corrosion and the search for compounds that can slow it down or even inhibit it.

In this context, the object of our work is to test the inhibitory efficacy of sodium benzoate and sodium acetate compounds against copper corrosion in sodium chloride (NaCl) medium with different concentrations and temperatures. We used stationary electrochemical techniques for the determination of electrochemical parameters.
The effect of sodium acetate and sodium benzoate, on the corrosion of copper in 3.5% NaCl, was tested at different concentrations and temperatures.
The results obtained clearly show that the copper electrode corrosion inhibition process is better in the case of the addition of sodium benzoate (10-2M ) at constant temperature (20 ° C). Unlike sodium benzoate, adding sodium acetate to NaCl solution (3.5%) has a negative effect and increases corrosion.
The inhibition study reveals that sodium benzoate offers the best inhibitory efficacy in this medium at room temperature, whereas sodium acetate is effective at a temperature of 40 ° C.

Key words: Corrosion, Inhibitors, Sodium benzoate, Sodium acetate, Copper, Temperature, Concentrations.
Citation

M. BERARMA Khedidja, (2021-11-10), "Effect of organic compounds on corrosion inhibition of copper in chloride media", [international] 1st international Webinar on Biological and Chemical (10/11-November, 2021.) Blida , Blida, Algeria

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2021-09-17

Corrosion study of Ni/Al2O3 composite coatings on copper support.

Corrosion is that the process during which a metal is destroyed by a chemical or electrochemical reactions with substances in its environment. Corrosion may be a dangerous and very costly problem , which can often cause impairment of the function of the metal, the environment, or the technical system of which these form a part.
Recognizing the symptoms and mechanism of a corrosion problem is an important preliminary step on the road to finding a convenient solution. One of the most common techniques used to prevent the corrosion is applying a protective coating of another metal that is more difficult to oxidize.
The present work was focused on electrodeposition and characterization composite deposits of Ni/Al2O3 on a copper substrate. These deposits are obtained from watts bath without additives. The oxide is used in electrochemical deposition of a substrate within sufficient properties. Ni and Ni– Al2O3 films were galvanostatically deposited on copper substrate from nickel sulfate bath. The composite coatings were characterized by using electrochemical methods such as open circuit potential (ocp) measurements, polarization curves and electrochemical impedance spectroscopy. The corrosion tests in an aggressive 3.5% NaCl solution indicate a reduced electrochemical activity and a high corrosion resistance in the case of composite deposits compared to the deposition of pure Ni, being confirmed the beneficial effect of the incorporation of Al2O3 into the Ni matrix. The best results are obtained for a concentration of 5 g / l of Al2O3. The results of the impedance are in agreement with the results of the currents of corrosion .
Keys word : Corrosion, electrolytic codeposition, nickel composite
Citation

M. BERARMA Khedidja, (2021-09-17), "Corrosion study of Ni/Al2O3 composite coatings on copper support.", [international] 2ème Séminaire international sur les sciences de la matière (physique et chimie) Le 17 - 18 Septembre 2021 (Webinaire Oran, 31000, Algeria , Université USTO, Bir El-djir -Oran

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2019-11-11

Inhibition de la corrosion de l’alliage de l’aluminium 2017A par l’acétate de sodium

Le sujet de ce travail porte sur un processus physico-chimique fondamental : la corrosion des métaux. La corrosion des surfaces métalliques a un énorme impact économique et environnemental négatif avec un coût estimé, lié aux dommages de la corrosion dans le monde, d'environ 2 milliards d'euros par an.
Toute amélioration de la protection contre la corrosion présente donc un avantage économique important. L'approche scientifique développée dans ce travail est orientée vers la compréhension des phénomènes liés à la corrosion et la recherche de composés permettant de la ralentir, voire de l’inhiber.

Les propriétés physico-chimiques intéressantes et les éventuelles applications technologiques de l’aluminium et ses alliages [1,2] nous ont motivés pour contribuer à l’étude du comportement électrochimiques vis-à-vis de la corrosion dans un milieu corrosif NaCl (3.5%) en absence et en présence de l’acétate de sodium (CH3COONa).
Le comportement à la corrosion aqueuse de ces alliages a été étudié dans une solution de NaCl (3.5%) M par le suivi de l’évolution du potentiel en circuit ouvert (OCP), le tracé des courbes de polarisation potentio-dynamique et la spectroscopie d’impédance électrochimique (SIE).
L’influence des paramètres, tels que le pH de la solution et la durée d’immersion, sur le comportement à la corrosion de ces alliages a été analysée.

Mots clés: Alliages d’aluminium, Corrosion, Polarisation potentio-dynamique, Spectroscopie d’impédance électrochimique
Citation

M. BERARMA Khedidja, (2019-11-11), "Inhibition de la corrosion de l’alliage de l’aluminium 2017A par l’acétate de sodium", [international] International conference on Mechanics and Materials (ICMM19) Setif, 11- 12 /11/ 2019 , Ferhat Abbas, Setif 1 University. Institute of Optics and Precision Mechanics

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2018

Galvanostatic electrodeposition thin film of nickel with TiO2 nanoparticles on copper substrate from nickel sulfate bath.

The aim of this work was to produce and to characterize composite deposits of nickel titanium dioxide on copper substrate. These deposits are obtained from watts bath without additives [1]. Titanium dioxide is one of the most important oxides used in the engineering materials. The oxide is used in electrochemical deposition of a substrate within sufficient properties.
Ni and Ni–TiO2 films were galvanostatically deposited on copper substrate from nickel sulfate bath. The composite coatings of nickel incorpating TiO2 nanoparticules were characterized by using electrochemical methodes such as open circuit potential (ocp) measurements, polarization curves and electrochemical impedances spectroscopy, the corrosion behavior of the nickel-TiO2 coating was examined. The corrosion tests in an agressive 3.5% NaCl solution indicate a reduced electrochemical activity and a high corrosion resistance in the case of composite deposits compared to the deposition of pure Ni, being confirmed the beneficial effect of the incorporation of TiO2 into the Ni matrix. The best results are obtained for a concentration of 5 g / l of TiO2.The results of the impedances are in agreement with the results of the currents of corrosion and the resistance of polarization which indicate the best resistance to corrosion in the case of the deposition of Ni obtained from the bath in the presence of 5 g / l TiO2
Keys word : Corrosion, electrolytic codeposition, nickel composite coating,
Citation

M. BERARMA Khedidja, (2018), "Galvanostatic electrodeposition thin film of nickel with TiO2 nanoparticles on copper substrate from nickel sulfate bath.", [international] International Conference on Materials Science 2018 (ICMS2018 –Sétif 12-14 Septembre) , Ferhat ABBAS SETIF1 University, ALGERIA

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Corrosion behavior of composite coatings obtained by electrolytic codeposition of nickel with TiO2 nanoparticles

Titanium dioxide is one of the most important oxides used in the engineering materials. The oxide is used in electrochemical deposition of a substrate within sufficient properties.
The objective of this work is the characterization of the composite deposits nickel titanium dioxide on copper substrate. These deposits are obtained from watts bath without additives [1]. The composite coatings of nickel incorpating TiO2 nanoparticules were obtained and characterized by using electrochemical methodes such as open circuit potential (ocp) measurements, polarization curves and electrochemical impedances spectroscopy, the corrosion behavior of the nickel-TiO2 coating was examined. The corrosion parameters determined from the polarization curves recorded in 3.5% NaCl indicate that the corrosion process on nickel-TiO2 composite surface is slower than on pure nickel. The impedance spectra recorded at the ocp showed in all cases an increase of polarization resistance in time .

[1] D. Peltcher, ‘Industrial Electrochemistry, Chapman & Hall, New York, (1984) , p. 184. Chap.
Keys word : Corrosion, electrolytic codeposition, nickel composite coating, TiO2nanoparticles
Citation

M. BERARMA Khedidja, (2018), "Corrosion behavior of composite coatings obtained by electrolytic codeposition of nickel with TiO2 nanoparticles", [international] International Symposium on Materials Chemistry (Boumerdes 19, 20 , 21 Mars 2018) , Université M’hamed Bougara Boumerdès

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2016-12-15

Theoretical investigation of structural, electronic and thermodynamic properties of CrO2compound.

The structural, electronic and thermodynamic properties of CrO2 compound have been performed by first-principles density functional [1] calculations using the full linearized augmented plane wave (FP-LAPW) [2] method as implemented in the WIEN2k code[3]. We employed the local density approximation (LDA) [4] and generalized gradient approximation (GGA) [5] for the exchange-correlation (XC) potential. Also, we have used the Engel-Vosko GGA formalism) [6], which optimizes the corresponding potential for band structure and density of states. Ground state properties such as the lattice parameters (a, b and c), bulk modulus B and its pressure derivative B`, have been directly calculated and compared to previous experimental and theoretical results when available. The energy gaps obtained using (EV-GGA) approximation are in reasonable agreement with experiment. Finally, by using a quasi-harmonic Debye model, thermodynamic properties is also calculated and analyzed. The effect of temperature and pressure on the bulk modulus, volume and heat capacities are discussed
Citation

M. BERARMA Khedidja, (2016-12-15), "Theoretical investigation of structural, electronic and thermodynamic properties of CrO2compound.", [international] 2ème Journée Internationales de Physique de Constantine (Décembre 2016) , UNIVERSITE des Frères MONTOURI CONSTANTINE 1

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2016-11-11

Investigation of electronic structure and thermodynamic properties of quaternary Li-containing chalcogenide Diamond-Like Semiconductors

Using first-principles calculations based on density functional theory, the structural, electronic
and thermodynamic properties of Li2CdGeS4 and Li2CdSnS4 compounds are investigated. We
confirmed that both Li2CdGeS4 and Li2CdSnS4 are diamond-like semiconductors of the wurtzstannite
structure type based on that of diamond in terms of tetrahedra volume. All the tetrahedra
are almost regular with major distortion from the ideal occurring in the LiS4 tetrahedron, with
values for S-Li-S ranging from 105.69° to 112.84° in the Li2CdGeS4 compound. Furthermore,
the Cd-S bond possesses a stronger covalent bonding strength than the Li/Ge-S bonds. In
addition, the inter-distances in Li2CdSnS4 show a larger spread than the distances in the
Li2CdGeS4 compound. The electronic structures have been calculated to understand the bonding
mechanism in quaternary Li-containing chalcogenide diamond-like semiconductors. Our results
show that Li2CdGeS4 and Li2CdSnS4 are semiconductors with a direct band gap of 2.79 and
2.42 eV and exhibit mixed ionic-covalent bonding. It is also noted that replacing Ge by Sn leads
to a decrease in the band gap; this behavior is explained in terms of bond lengths and
electronegativity differences between atoms. Optical properties, including the dielectric function,
reflectivity, and absorption coefficient, each as a function of photon energy are calculated and
show an optical anisotropy for Li2CdGeS4 and Li2CdSnS4. The static dielectric constant e1 (0)
and static refractive index n (0) decrease when Ge is replaced by Sn. The influence of pressures
and temperatures on the thermodynamic properties like the specific heat at constant volume Cv,
and at constant pressure Cp, the Debye temperature QD, the entropy S and the Grüneisen
parameter g have been predicted at enlarged pressure and temperature ranges. The principal
aspect from the obtained results is the close similarity of both compounds.
Keywords: semiconductors, ab initio calculations, crystal structure, electronic structure,
thermodynamic properties, dielectric function
Citation

M. BERARMA Khedidja, (2016-11-11), "Investigation of electronic structure and thermodynamic properties of quaternary Li-containing chalcogenide Diamond-Like Semiconductors", [national] Semiconductor Science and Technology , IOPscience

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