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Etude des matériaux ferroélectriques (céramiques et couches minces à base de niobates alcalino-terreux)et multicouches ferroélectriques-catalytiques pour capteur gaz

Abstract : This work deals with elaboration of ferroelectric and catalytic materials in form of powders, ceramics or thin films, for electronic and gas sensor applications. In a first step, a solid solution Sr, ^Ca-^KN^O^ (0 < X < 0.5) was synthesized by classical solid state reaction, and by a specific coprecipitation technique. In a second step, other TTB ferroelectrics phases belonging to the series BajANb50|S with (A = Na, K and Li) and Ba Na LixNb5O|; (0 < x < 1.2) were synthesized using first a classical solid state route (at 1100QC) and, secondly, a mechanosynthesis approach. The TTB phases, first prepared at room temperature via mechanosynthesis, were then heated at 800°C: X-ray diffraction showed that these phases were highly crystallized and that such synthesis required heating temperature lower than that required by solid state reaction (1100°C). Modifications of ferroelectric behavior close to Curie temperature were observed for samples prepared via sol ge! route. In a third step, thin films of Ba3NaNb5Oi; (BNN) phase and of BiJ2;Lao 75^1^0^ (BLT) phase were deposited on various types of substrates. Finally, a preliminary study of ferroelectric / catalytic multilayers was carried out. Ruthenium dioxide Ru02 was used as a catalyst for methane conversion into CO;. Thin films of ruthenium dioxide were deposited by spin coating process, on various substrates initially covered with Pt, SrBi2Ta209 (SET), Ba2NaNb;O|; (BNN) layers. Using FT1R spectroscopy and specific catalytic cell converting CH4 into CO2, RuC>2 layers exhibited variable conversion capacity. RuO2 films deposited on BNN layers seemed to present improved calalytic efficiency.
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https://tel.archives-ouvertes.fr/tel-00287332
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Submitted on : Wednesday, June 11, 2008 - 3:36:32 PM
Last modification on : Thursday, March 15, 2018 - 4:56:03 PM
Long-term archiving on: : Friday, May 28, 2010 - 7:13:59 PM

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  • HAL Id : tel-00287332, version 1

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Manar Khachane. Etude des matériaux ferroélectriques (céramiques et couches minces à base de niobates alcalino-terreux)et multicouches ferroélectriques-catalytiques pour capteur gaz. Matériaux. Université du Sud Toulon Var, 2007. Français. ⟨tel-00287332⟩

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