Hicham ES-SOUFI | Moulay Ismail University, Meknes, Morocco (original) (raw)
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Papers by Hicham ES-SOUFI
CRC Press eBooks, Jul 31, 2023
Glasses in the system 33.33[xNa2O-(1-x)Li2O]-2.5SrO-2.5TiO2-45B2O3-16.67P2O5 (0.0 ≤ x ≤ 1.0) were... more Glasses in the system 33.33[xNa2O-(1-x)Li2O]-2.5SrO-2.5TiO2-45B2O3-16.67P2O5 (0.0 ≤ x ≤ 1.0) were prepared by standard melt quenching procedures, and their physical properties were characterized by thermal analysis, density measurements. Their local structures were comprehensively characterized by Infrared spectroscopy (IR) and electron paramagnetic resonance (EPR). The variation of the glass transition temperature as a function of the glass compositions is non-linear. The infrared spectroscopy of the glasses has identified the presence of different structural grouping units in the glassy-matrix. It is found that the stretching and bending vibration modes of borate groups are more sensitive to the substitution of alkali elements. EPR experiments have shown the presence of Ti3+ centres in the glasses. The variation of the g-factor as a function of the Na/(Na+Li) ratio presents a minimum around (x=0.5). The composition non-linearity behavior of Tg, vibration bending mode, and g-factor...
Ceramics International, Jun 1, 2023
Journal of Materials Science: Materials in Electronics
Journal of Materials Research and Technology
Journal of Materials Research and Technology
Journal of Materials Science: Materials in Electronics
Crystals
Owing to their low dielectric loss and high permittivity values, dielectric ceramics have garnere... more Owing to their low dielectric loss and high permittivity values, dielectric ceramics have garnered a lot of interest from the scientific and industrial sectors. These properties allow for their downsizing and use in a variety of electronic circuits. This present work focuses on the impact of the substitution of W6+ with Mo6+ on the structural and dielectric features of the crystalline phases in a similar TTB structure within the Ba0.54Na0.46Nb1.29W(0.37−x)MoxO5 system, with 0 ≤ x ≤ 0.33 mol%. These crystalline phases were elaborated using the conventional solid-state reaction method and analyzed with XRD, Raman, and dielectric techniques. The Rietveld refinement method showed that all these phases are characterized by tetragonal structure and the P4bm space group. The Raman spectra corresponded well to a TTB-like structure, and all the bands were assigned. The dielectric measurements of the prepared ceramic samples facilitated the determination of their phase transition temperature ...
Crystals
Using the solid-state process, the new compound Ba0.54Na0.46Nb1.29W0.37O5 was effectively produce... more Using the solid-state process, the new compound Ba0.54Na0.46Nb1.29W0.37O5 was effectively produced in a single crystalline phase. The material’s characteristics were determined by X-ray diffraction and Raman techniques. The Rietveld method was applied to refine the structural properties of this sample using X-ray diffraction data and derive the diffraction line profile. The cell parameters a = b = 12.37843 ± 0.02 and c = 3.93526 ± 0.02 were accustomed to crystallizing this compound in the tetragonal tungsten bronze (TTB) structure of the space group P4bm. Thanks to Raman measurements, we were able to detect numerous vibration modes in this crystalline phase. The adsorption of methylene blue (MB) on crystalline phase was studied by UV–visible spectroscopy. On account of methylene blue adsorption on Ba0.54Na0.46Nb1.29W0.37O5, it was discovered that this material can be used to remove organic pollutants and thus be used for water treatment.
Dielectric Materials and Applications - ISyDMA’2016, 2016
Phosphate glasses of the compositions 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(3) (0 <= x <= 1... more Phosphate glasses of the compositions 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(3) (0 <= x <= 15, mol%) were prepared by the melt quenching method. The amorphous nature of these glasses was confi ...
Journal of Non-Crystalline Solids, 2017
A melt-quenching method is used to prepare homogeneous glasses inside the 20Li 2 O-(50-x)Li 2 WO ... more A melt-quenching method is used to prepare homogeneous glasses inside the 20Li 2 O-(50-x)Li 2 WO 4-xTiO 2-30P 2 O 5 (x = 0, 5, 8, 10 and 15 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-ray diffraction and differential scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. The determined parameters for the glasses such as density, molar volume and glass transition temperature (T g) depend strongly on the chemical composition of the glasses. The density and T g are found to decrease and increase with TiO 2 content, respectively. Infrared (IR) spectroscopy is used to characterize their structural approach. This technique has allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap, E g , and Urbach energy, ΔE, were evaluated. The optical band gap is found to depend on the glass composition and it decreases as the content of the TiO 2 increases.
A melt-quenched method is used to prepare homogeneous glasses inside the 20Na2O-(50-x)Na2WO4-xTiO... more A melt-quenched method is used to prepare homogeneous glasses inside the 20Na2O-(50-x)Na2WO4-xTiO2-30P2O5 (0≤x≤25 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-Ray diffraction and differencial scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. Some physical parameters for the glasses such as density, molar volume and glass transition temperature (Tg) are determined and depended strongly on the chemical composition of the glasses. The density and Tg showed the decrease and the increase with TiO2 content, respectively. Infrared spectroscopy (IR) and Raman spectroscopy are used to characterize their structural approach. These both techniques have allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap (Eg) and Urbach energy (DE) were evaluated. The optical band gap was fou...
Solid electrolytes of sodium ions were applied in many technologies, from chemical sensors to bat... more Solid electrolytes of sodium ions were applied in many technologies, from chemical sensors to batteries. In this work, we focused on the study of electrolytes-based phosphate glasses prepared within the system 20Na2O-(50-x)Na2WO4-xTiO2-30P2O5 (with 0≤x≤25 mol%). These glasses were elaborated via a melt-quenching method. The DSC technique was exploited to estimate the activation energy depending on the crystallization (Ec). Where the glass (x= 5) was characterized by Ec= 144.77 kJ/mol. Avrami parameter (n) allows determining the mechanism of crystallization. This parameter value is found around ≈ 2; it can anticipate that the crystallization mechanism is a one-dimensional, periodic landscape. The Raman spectroscopy analysis showed that the bonds constituting the framework of these glasses are essential constituted from the PO4 units. The insertion of TiO2 into the glass framework leads to formation of the new bonds P-O-Ti and/or Ti-O-Ti. Changing the Na2WO4 mol% by TiO2 mol% leads to...
New Journal of Glass and Ceramics
Glasses of the compositions 20Li 2 O-(50 − x)Li 2 WO 4-xFe 2 O 3-30P 2 O 5 where (x = 0, 1, 5, 8,... more Glasses of the compositions 20Li 2 O-(50 − x)Li 2 WO 4-xFe 2 O 3-30P 2 O 5 where (x = 0, 1, 5, 8, 10, 15 mol%) were elaborated by the melt-quenching route. Synthesized glasses are characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetric (DSC), and density determination. The XRD patterns confirmed the amorphous nature of samples, and IR spectra showed the structural groups and highlight the depolymerization of phosphate network with the introduction of iron oxide. It is found that the structural unit Q 2 converts to Q 1 and Q 0 as Fe 2 O 3 replaces Li 2 WO 4. Chemical durability tests on the glasses have shown that the compositions containing pyrophosphate (Q 1) and orthophosphate (Q 0) units are more water-resist. The electrical conductivity measurements were performed by complex impedance spectroscopy in the frequency range of 20-10 6 Hz at various temperatures from ambient to 400˚C. It is found that the conductivity is activated thermally and follows an Arrhenius law. The obtained electrical data were analyzed by the modulus formalism and dielectric formalism. The determined asymmetric nature of max M M ′′ ′′ spectra suggested that the relaxation behavior is non-Debye and characterized by the stretched exponent parameter β < 1.
CRC Press eBooks, Jul 31, 2023
Glasses in the system 33.33[xNa2O-(1-x)Li2O]-2.5SrO-2.5TiO2-45B2O3-16.67P2O5 (0.0 ≤ x ≤ 1.0) were... more Glasses in the system 33.33[xNa2O-(1-x)Li2O]-2.5SrO-2.5TiO2-45B2O3-16.67P2O5 (0.0 ≤ x ≤ 1.0) were prepared by standard melt quenching procedures, and their physical properties were characterized by thermal analysis, density measurements. Their local structures were comprehensively characterized by Infrared spectroscopy (IR) and electron paramagnetic resonance (EPR). The variation of the glass transition temperature as a function of the glass compositions is non-linear. The infrared spectroscopy of the glasses has identified the presence of different structural grouping units in the glassy-matrix. It is found that the stretching and bending vibration modes of borate groups are more sensitive to the substitution of alkali elements. EPR experiments have shown the presence of Ti3+ centres in the glasses. The variation of the g-factor as a function of the Na/(Na+Li) ratio presents a minimum around (x=0.5). The composition non-linearity behavior of Tg, vibration bending mode, and g-factor...
Ceramics International, Jun 1, 2023
Journal of Materials Science: Materials in Electronics
Journal of Materials Research and Technology
Journal of Materials Research and Technology
Journal of Materials Science: Materials in Electronics
Crystals
Owing to their low dielectric loss and high permittivity values, dielectric ceramics have garnere... more Owing to their low dielectric loss and high permittivity values, dielectric ceramics have garnered a lot of interest from the scientific and industrial sectors. These properties allow for their downsizing and use in a variety of electronic circuits. This present work focuses on the impact of the substitution of W6+ with Mo6+ on the structural and dielectric features of the crystalline phases in a similar TTB structure within the Ba0.54Na0.46Nb1.29W(0.37−x)MoxO5 system, with 0 ≤ x ≤ 0.33 mol%. These crystalline phases were elaborated using the conventional solid-state reaction method and analyzed with XRD, Raman, and dielectric techniques. The Rietveld refinement method showed that all these phases are characterized by tetragonal structure and the P4bm space group. The Raman spectra corresponded well to a TTB-like structure, and all the bands were assigned. The dielectric measurements of the prepared ceramic samples facilitated the determination of their phase transition temperature ...
Crystals
Using the solid-state process, the new compound Ba0.54Na0.46Nb1.29W0.37O5 was effectively produce... more Using the solid-state process, the new compound Ba0.54Na0.46Nb1.29W0.37O5 was effectively produced in a single crystalline phase. The material’s characteristics were determined by X-ray diffraction and Raman techniques. The Rietveld method was applied to refine the structural properties of this sample using X-ray diffraction data and derive the diffraction line profile. The cell parameters a = b = 12.37843 ± 0.02 and c = 3.93526 ± 0.02 were accustomed to crystallizing this compound in the tetragonal tungsten bronze (TTB) structure of the space group P4bm. Thanks to Raman measurements, we were able to detect numerous vibration modes in this crystalline phase. The adsorption of methylene blue (MB) on crystalline phase was studied by UV–visible spectroscopy. On account of methylene blue adsorption on Ba0.54Na0.46Nb1.29W0.37O5, it was discovered that this material can be used to remove organic pollutants and thus be used for water treatment.
Dielectric Materials and Applications - ISyDMA’2016, 2016
Phosphate glasses of the compositions 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(3) (0 <= x <= 1... more Phosphate glasses of the compositions 20Li(2)O-(50-x)Li2WO4-xTiO(2)-30P(2)O(3) (0 <= x <= 15, mol%) were prepared by the melt quenching method. The amorphous nature of these glasses was confi ...
Journal of Non-Crystalline Solids, 2017
A melt-quenching method is used to prepare homogeneous glasses inside the 20Li 2 O-(50-x)Li 2 WO ... more A melt-quenching method is used to prepare homogeneous glasses inside the 20Li 2 O-(50-x)Li 2 WO 4-xTiO 2-30P 2 O 5 (x = 0, 5, 8, 10 and 15 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-ray diffraction and differential scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. The determined parameters for the glasses such as density, molar volume and glass transition temperature (T g) depend strongly on the chemical composition of the glasses. The density and T g are found to decrease and increase with TiO 2 content, respectively. Infrared (IR) spectroscopy is used to characterize their structural approach. This technique has allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap, E g , and Urbach energy, ΔE, were evaluated. The optical band gap is found to depend on the glass composition and it decreases as the content of the TiO 2 increases.
A melt-quenched method is used to prepare homogeneous glasses inside the 20Na2O-(50-x)Na2WO4-xTiO... more A melt-quenched method is used to prepare homogeneous glasses inside the 20Na2O-(50-x)Na2WO4-xTiO2-30P2O5 (0≤x≤25 mol%) system. The amorphous and glassy states of the glasses are evidenced by the X-Ray diffraction and differencial scanning calorimetry (DSC) analysis, respectively. The glasses were found to be colorless. Some physical parameters for the glasses such as density, molar volume and glass transition temperature (Tg) are determined and depended strongly on the chemical composition of the glasses. The density and Tg showed the decrease and the increase with TiO2 content, respectively. Infrared spectroscopy (IR) and Raman spectroscopy are used to characterize their structural approach. These both techniques have allowed the identification of different phosphate structural units mainly pyrophosphate and metaphosphate in their structure. From the absorption edge studies, the values of the optical band gap (Eg) and Urbach energy (DE) were evaluated. The optical band gap was fou...
Solid electrolytes of sodium ions were applied in many technologies, from chemical sensors to bat... more Solid electrolytes of sodium ions were applied in many technologies, from chemical sensors to batteries. In this work, we focused on the study of electrolytes-based phosphate glasses prepared within the system 20Na2O-(50-x)Na2WO4-xTiO2-30P2O5 (with 0≤x≤25 mol%). These glasses were elaborated via a melt-quenching method. The DSC technique was exploited to estimate the activation energy depending on the crystallization (Ec). Where the glass (x= 5) was characterized by Ec= 144.77 kJ/mol. Avrami parameter (n) allows determining the mechanism of crystallization. This parameter value is found around ≈ 2; it can anticipate that the crystallization mechanism is a one-dimensional, periodic landscape. The Raman spectroscopy analysis showed that the bonds constituting the framework of these glasses are essential constituted from the PO4 units. The insertion of TiO2 into the glass framework leads to formation of the new bonds P-O-Ti and/or Ti-O-Ti. Changing the Na2WO4 mol% by TiO2 mol% leads to...
New Journal of Glass and Ceramics
Glasses of the compositions 20Li 2 O-(50 − x)Li 2 WO 4-xFe 2 O 3-30P 2 O 5 where (x = 0, 1, 5, 8,... more Glasses of the compositions 20Li 2 O-(50 − x)Li 2 WO 4-xFe 2 O 3-30P 2 O 5 where (x = 0, 1, 5, 8, 10, 15 mol%) were elaborated by the melt-quenching route. Synthesized glasses are characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetric (DSC), and density determination. The XRD patterns confirmed the amorphous nature of samples, and IR spectra showed the structural groups and highlight the depolymerization of phosphate network with the introduction of iron oxide. It is found that the structural unit Q 2 converts to Q 1 and Q 0 as Fe 2 O 3 replaces Li 2 WO 4. Chemical durability tests on the glasses have shown that the compositions containing pyrophosphate (Q 1) and orthophosphate (Q 0) units are more water-resist. The electrical conductivity measurements were performed by complex impedance spectroscopy in the frequency range of 20-10 6 Hz at various temperatures from ambient to 400˚C. It is found that the conductivity is activated thermally and follows an Arrhenius law. The obtained electrical data were analyzed by the modulus formalism and dielectric formalism. The determined asymmetric nature of max M M ′′ ′′ spectra suggested that the relaxation behavior is non-Debye and characterized by the stretched exponent parameter β < 1.