| Titre : |
Préparation et étude électrique de poudres nanocristallines de ZnO pur et dopé par différents oxydes. |
| Type de document : |
texte imprimé |
| Auteurs : |
Saliha Hamdellou, Auteur ; Kamel Guergouri, Directeur de thèse |
| Editeur : |
جامعة الإخوة منتوري قسنطينة |
| Année de publication : |
2017 |
| Importance : |
169 f. |
| Format : |
30 cm. |
| Note générale : |
2 copies imprimées disponibles
|
| Langues : |
Français (fre) |
| Catégories : |
Français - Anglais
Physique
|
| Tags : |
ZnO Zn-x%Co-O Sol-Gel Micro-onde Frittage Varistance Grains I(V) Sintering Varistor ميكروويف تلبيد مقاومة متغيرة |
| Index. décimale : |
530 Physique |
| Résumé : |
The goal of this thesis is to realize zinc oxide (ZnO) varistors doped with cobalt (Co)
from nanosized powders, in order to explore the relationship between the reduction in particle
size and the varistor effect. To do this, nano-powders of pure ZnO and doped with cobalt (Co)
have been prepared by soft chemistry method known by the name of Sol-Gel. The structural
and morphological characterizations were obtained through XRD spectra and Fourier
Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD
results indicate that the powders obtained from the two types of precursors have a hexagonal
structure « würtzite », a size of nano-particles without any new phase for either pure ZnO or
Zn-Co-x% O. A decrease in particle size by increasing the Co content up to 7% is however to
be noted. The results obtained from the XRD characterization are confirmed by the (FTIR)
analysis.The study of various varistors by microwave sintering, showed: a homogeneous
distribution of grains as observed by SEM and a density reaching 93% in spite of the very
short sintering duration.Electrical characterization I (V) of these ceramics shows a marked
non-linear behavior in the sintering temperature range 1000 °C and 1075 °C, resulting in an
improvement of the coefficient α and the outbreak field, which increased significantly with
the decrease in grain size.The obtained results encourage the use of this model of
nanostructured varistors for applications in microelectronics. |
| Diplôme : |
Doctorat en sciences |
| En ligne : |
../theses/physique/HAM7030.pdf |
| Format de la ressource électronique : |
pdf |
| Permalink : |
https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10569 |
Préparation et étude électrique de poudres nanocristallines de ZnO pur et dopé par différents oxydes. [texte imprimé] / Saliha Hamdellou, Auteur ; Kamel Guergouri, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2017 . - 169 f. ; 30 cm. 2 copies imprimées disponibles
Langues : Français ( fre)
| Catégories : |
Français - Anglais
Physique
|
| Tags : |
ZnO Zn-x%Co-O Sol-Gel Micro-onde Frittage Varistance Grains I(V) Sintering Varistor ميكروويف تلبيد مقاومة متغيرة |
| Index. décimale : |
530 Physique |
| Résumé : |
The goal of this thesis is to realize zinc oxide (ZnO) varistors doped with cobalt (Co)
from nanosized powders, in order to explore the relationship between the reduction in particle
size and the varistor effect. To do this, nano-powders of pure ZnO and doped with cobalt (Co)
have been prepared by soft chemistry method known by the name of Sol-Gel. The structural
and morphological characterizations were obtained through XRD spectra and Fourier
Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD
results indicate that the powders obtained from the two types of precursors have a hexagonal
structure « würtzite », a size of nano-particles without any new phase for either pure ZnO or
Zn-Co-x% O. A decrease in particle size by increasing the Co content up to 7% is however to
be noted. The results obtained from the XRD characterization are confirmed by the (FTIR)
analysis.The study of various varistors by microwave sintering, showed: a homogeneous
distribution of grains as observed by SEM and a density reaching 93% in spite of the very
short sintering duration.Electrical characterization I (V) of these ceramics shows a marked
non-linear behavior in the sintering temperature range 1000 °C and 1075 °C, resulting in an
improvement of the coefficient α and the outbreak field, which increased significantly with
the decrease in grain size.The obtained results encourage the use of this model of
nanostructured varistors for applications in microelectronics. |
| Diplôme : |
Doctorat en sciences |
| En ligne : |
../theses/physique/HAM7030.pdf |
| Format de la ressource électronique : |
pdf |
| Permalink : |
https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10569 |
|
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