Yazar "Turkoglu, Orhan" seçeneğine göre listele

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    Fabrication and Characterization of Dysprosium-Doped Bismuth Oxide Films for IT-SOFCs via Slurry Spin Coating Technique
    (WILEY, 2015) Ersoy, Ersay; Cakar, Soner; Yildiz, Esra; Yilmaz, Serdar; Turkoglu, Orhan; Sarioz, Ozlem
    The production and stabilization of the fcc-phase Bi2O3 solid solution (delta-DSB) in the binary system of (Bi2O3)(1-x)(Dy2O3)(x) have been investigated in the doping range of 0.10 <= x <= 0.25 by adding Dy2O3 into pure alpha-Bi2O3. All delta-DSB samples were stabilized and exhibited single d-phase at 800 degrees C. Thick film solid electrolytes were produced by the spin coating method. All of the coating and sintering parameters were optimized. Crystallographic, microstructural, and electrical characterizations were made for the produced films. The highest value of conductivity was similar to 1-10 Scm(-1) for 11-15 mol% delta-DSB film samples. The electrical conductivity curves of samples showed regular increase.
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    Synthesis and characterization of gamma-Bi2O3 based solid electrolyte doped with Nb2O5
    (INDIAN ACAD SCIENCES, 2014) Ozlu, Handan; Cakar, Soner; Bilir, Caner; Ersoy, Ersay; Turkoglu, Orhan
    gamma-phase bismuth oxide is a well known high oxygen ion conductor and can be used as an electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). This study aims to determine new phases of Bi2O3-Nb2O5 binary system and the temperature dependence of the electrical transport properties. The reaction products obtained in open air atmosphere were characterized by X-ray powder diffractions (XRD). The unit cell parameters were defined from the indexes of the powder diffraction patterns. The gamma-Bi2O3 crystal system were obtained by doping 0.01 < mole% Nb2O5 < 0.04 at 750 degrees C for 48 and 96 h. Thermal behaviour and thermal stability of the phases were investigated by thermal analysis techniques. Surface and grain properties of the related phases were determined by SEM analysis. The temperature dependence of the electrical properties of gamma-Bi2O3 solid solution was measured by four-point probe d.c. conductivity method. In the investigated system, the highest value of conductivity was observed for sigma(T)=0.016 ohm(-1) cm(-1) at 650 degrees C on 4 mole% Nb2O5 addition. The electrical conductivity curves of studied materials revealed regular increase with temperature in the form of the Arrhenius type conductivity behaviour.