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Auteur Mourad Khechba |
Documents disponibles écrits par cet auteur (2)
Affiner la recherche Interroger des sources externesCaractérisation de la réaction interfaciale entre une couche mince de tungsèe et un substrat d'acier / Mourad Khechba
Titre : Caractérisation de la réaction interfaciale entre une couche mince de tungsèe et un substrat d'acier Type de document : texte imprimé Auteurs : Mourad Khechba ; Univ. de Constantine, Éditeur scientifique ; Rachid Halimi, Directeur de thèse Année de publication : 2008 Importance : 82 f. Note générale : 01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Thin films magnetron sputtering coating tungsten carbides Couches Minces pulvérisation cathodique RF revêtement tungstène carbures Index. décimale : 530 Physique Résumé : In this work, we characterize the reaction of tungsten thin layer (6µm thickness) deposited by rf magnetron sputtering technique at 500°C, during 60min, with a steel XC70 substrate (according to AFNOR) containing 0,7 % of carbon.
The samples (thin layer of tungsten + steel substrate) were submitted to thermal treatments in vacuum at various temperatures (500°C-1000°C) and during different times. The specimens are characterized by X ray diffraction (XRD), optic microscopy, scanning electron microscopy (SEM) and by Vickers tests for the measurements of micro-hardness.
The main obtained results can be summarized as follows:
In the temperature range 500-800°C, no formation of tungsten carbides was observed. However, the annealing at a temperature greater than or equal to 900°C promotes the reaction between the constituents of the samples (W, Fe, C), and hence the formation of W2C carbide. No other compounds were detected.
The micro-hardness measured by Vickers tests, increases with the rise in temperature, particularly from 900°C. The increase in the hardness is due, probably, to the formation and growth of W2C carbide.
It is also shown that, the micro-hardness decreases with increasing of the applied load and the depth of penetration until substrate.
For thin coating (2 and 4 μm):
W2C carbide is formed with annealing at 800 ° C for 30 min for all samples.
The formation of ternary carbide Fe3W3C takes place after annealing at T≥ 900°C.
The mono carbide WC is obtained with an annealing at 1000°C for 60 min, only in
the case of the thinner coating (2 μm).
The morphology of the surface samples depends on the temperature and duration of thermal annealing.Diplôme : Magistère En ligne : ../theses/physique/KHE5087.pdf Permalink : index.php?lvl=notice_display&id=3468 Caractérisation de la réaction interfaciale entre une couche mince de tungsèe et un substrat d'acier [texte imprimé] / Mourad Khechba ; Univ. de Constantine, Éditeur scientifique ; Rachid Halimi, Directeur de thèse . - 2008 . - 82 f.
01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Thin films magnetron sputtering coating tungsten carbides Couches Minces pulvérisation cathodique RF revêtement tungstène carbures Index. décimale : 530 Physique Résumé : In this work, we characterize the reaction of tungsten thin layer (6µm thickness) deposited by rf magnetron sputtering technique at 500°C, during 60min, with a steel XC70 substrate (according to AFNOR) containing 0,7 % of carbon.
The samples (thin layer of tungsten + steel substrate) were submitted to thermal treatments in vacuum at various temperatures (500°C-1000°C) and during different times. The specimens are characterized by X ray diffraction (XRD), optic microscopy, scanning electron microscopy (SEM) and by Vickers tests for the measurements of micro-hardness.
The main obtained results can be summarized as follows:
In the temperature range 500-800°C, no formation of tungsten carbides was observed. However, the annealing at a temperature greater than or equal to 900°C promotes the reaction between the constituents of the samples (W, Fe, C), and hence the formation of W2C carbide. No other compounds were detected.
The micro-hardness measured by Vickers tests, increases with the rise in temperature, particularly from 900°C. The increase in the hardness is due, probably, to the formation and growth of W2C carbide.
It is also shown that, the micro-hardness decreases with increasing of the applied load and the depth of penetration until substrate.
For thin coating (2 and 4 μm):
W2C carbide is formed with annealing at 800 ° C for 30 min for all samples.
The formation of ternary carbide Fe3W3C takes place after annealing at T≥ 900°C.
The mono carbide WC is obtained with an annealing at 1000°C for 60 min, only in
the case of the thinner coating (2 μm).
The morphology of the surface samples depends on the temperature and duration of thermal annealing.Diplôme : Magistère En ligne : ../theses/physique/KHE5087.pdf Permalink : index.php?lvl=notice_display&id=3468 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité KHE/5087 KHE/5087 Thèse Bibliothèque principale Thèses Disponible
Titre : Elaboration et étude des couches minces d’oxyde d’étain Type de document : texte imprimé Auteurs : Mourad Khechba, Auteur ; Abderaheman Bouabellou, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 97 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Couche mince SnO2 dopage Sol-Gel DRX AFM Spectroscopie Raman UV-Vis Ellipsométrie spectroscopique (SE) Thin films doping Raman spectroscopy UV-Visible Ellipsometry Spectroscopic الشرائح الرقيقة أكسيد القصدير التطعيم-سائل-جامد حيود الاشعة السينية مجهر القوة الذرية مطيافية رامان مطيافية الاشعة فوق البنفسجية والمرئية والمطياف الاهليجي Index. décimale : 530 Physique Résumé : This work is devoted to the development of the tin oxide thin films by the sol-gel method. The effect of the annealing temperature, the number of layers and the doping on the structural and optical properties of the films obtained were investigated. The obtained films are characterized by X-ray diffraction (DRX), RAMAN spectroscopy, atomic force microscopy (AFM), UV-Visible spectroscopy and ellipsometry spectroscopic. Raman spectroscopy results show that the SnO2 thin films are crystallizes in rutile phase. A good crystallization is observed after 3 coats. The results of optical characterization show that all the films are transparent (75 to 85% optical transmittance) in the visible and The energy band gap of all the samples lies in the range of 3.63eV– 3.89eV With regard to doping, undoped and doped tin oxide thin films (SnO2:Cd, SnO2:Al) were deposited by Sol Gel Dip Coating method on glass and silicon Si(100) substrates. The DRX shows that all the films deposited on glass substrates have an amorphous structure. On the other hand, the films deposited on Si (100) substrate crystallize in the rutile phase, with a preferential orientation along the axis (310). AFM observations of the surface show that the doping rate affects the roughness. The grain size and the roughness of the samples decrease with the increase of the doping concentration. The SnO2, SnO2:Cd and SnO2:Al thin films are transparent in the visible region and opaque in the ultraviolet region. The band gap, determined from the transmission spectra for the deposited films, also decreases with the increase in the doping rate (from 06 to 10% Cd, and from 04 to 06% Al). In addition, the increase of the cadmium and aluminum doping concentration causes a slight increase in the refractive index.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/KHE7337.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10987 Elaboration et étude des couches minces d’oxyde d’étain [texte imprimé] / Mourad Khechba, Auteur ; Abderaheman Bouabellou, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 97 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Couche mince SnO2 dopage Sol-Gel DRX AFM Spectroscopie Raman UV-Vis Ellipsométrie spectroscopique (SE) Thin films doping Raman spectroscopy UV-Visible Ellipsometry Spectroscopic الشرائح الرقيقة أكسيد القصدير التطعيم-سائل-جامد حيود الاشعة السينية مجهر القوة الذرية مطيافية رامان مطيافية الاشعة فوق البنفسجية والمرئية والمطياف الاهليجي Index. décimale : 530 Physique Résumé : This work is devoted to the development of the tin oxide thin films by the sol-gel method. The effect of the annealing temperature, the number of layers and the doping on the structural and optical properties of the films obtained were investigated. The obtained films are characterized by X-ray diffraction (DRX), RAMAN spectroscopy, atomic force microscopy (AFM), UV-Visible spectroscopy and ellipsometry spectroscopic. Raman spectroscopy results show that the SnO2 thin films are crystallizes in rutile phase. A good crystallization is observed after 3 coats. The results of optical characterization show that all the films are transparent (75 to 85% optical transmittance) in the visible and The energy band gap of all the samples lies in the range of 3.63eV– 3.89eV With regard to doping, undoped and doped tin oxide thin films (SnO2:Cd, SnO2:Al) were deposited by Sol Gel Dip Coating method on glass and silicon Si(100) substrates. The DRX shows that all the films deposited on glass substrates have an amorphous structure. On the other hand, the films deposited on Si (100) substrate crystallize in the rutile phase, with a preferential orientation along the axis (310). AFM observations of the surface show that the doping rate affects the roughness. The grain size and the roughness of the samples decrease with the increase of the doping concentration. The SnO2, SnO2:Cd and SnO2:Al thin films are transparent in the visible region and opaque in the ultraviolet region. The band gap, determined from the transmission spectra for the deposited films, also decreases with the increase in the doping rate (from 06 to 10% Cd, and from 04 to 06% Al). In addition, the increase of the cadmium and aluminum doping concentration causes a slight increase in the refractive index.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/KHE7337.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10987 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité KHE/7337 KHE/7337 Thèse Bibliothèque principale Thèses Disponible
