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Author: search.filters.author.Vittayakorn, WanwilaiSubject: search.filters.subject.Barium zirconate

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    Dielectric relaxation behavior of BaZrO3 ceramics at low temperature
    (2020-10-15)
    Pulphol, Phieraya
    ;
    Vittayakorn, Naratip
    ;
    Vittayakorn, Wanwilai
    ;
    Kolodiazhnyi, Taras
    Dielectric behavior of nominally pure BaZrO<inf>3</inf>, Sc-doped BaZrO<inf>3</inf> and Sc + Nb-co-doped BaZrO<inf>3</inf> ceramics is reported in this paper. Several dielectric anomalies are detected in the pure and Sc-doped BaZrO<inf>3</inf> in temperature interval of 2–700 K. The Arrhenius-type dielectric relaxation has activation energies ranging from ca. 10 meV–800 meV. Annealing in Ar atmosphere at 1200 °C alters the intensity of the dielectric loss peaks especially in the Sc-doped BaZrO<inf>3.</inf> In contrast, none of the dielectric relaxation anomalies were found in Sc + Nb-co-doped BaZrO<inf>3</inf>. It is proposed that at least some of the dielectric peaks originate from the proton dynamics which includes high temperature migration, intermediate-temperature rotation and low-temperature phonon-assisted proton tunneling.
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    Sonochemical synthesis of monodispersed perovskite barium zirconate (BaZrO3) by using an ethanol-water mixed solvent
    (2015-07-01)
    Charoonsuk, Thitirat
    ;
    Vittayakorn, Wanwilai
    ;
    Vittayakorn, Naratip
    ;
    Seeharaj, Panpailin
    ;
    Maensiri, Santi
    Perovskite barium zirconate (BaZrO<inf>3</inf>) was synthesized successfully in an ethanol-water mixed solvent under ultrasonic irradiation. Four compositions, including 0%, 30%, 50%, and 70% by volume of ethanol in ethanol/water mixed solvent, were used. The effect of ethanol content and irradiation time on the phase formation and morphology of product particles was studied and discussed. As a result, a pure perovskite BaZrO<inf>3</inf> phase was formed completely at a short irradiation time of about 15 min in 70% by volume of ethanol without the calcination process. The average particles size decreases and particle size distribution becomes narrower by increasing the percentage of ethanol volume. On the other hand, the monodispersibility of BaZrO<inf>3</inf> particles was improved significantly through ultrasonic irradiation.
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    Synthesis of monodispersed perovskite barium zirconate (BaZrO3) by the sonochemical method
    (2013-01-01)
    Charoonsuk, Piyanut
    ;
    Baitahe, Rattanai
    ;
    Vittayakorn, Wanwilai
    ;
    Atiwongsangthong, Narin
    ;
    Muanghua, Rangson
    Barium zirconate (BaZrO<inf>3</inf>) was synthesized successfully by the sonochemical method. The monophase of BaZrO<inf>3</inf> was formed completely in short irradiation time without the calcination process. X-ray diffraction, Fourier transform and Raman spectroscopy were used to characterize formation of the perovskite BaZrO<inf>3</inf> phase, which occurs in a 60 minute single phase with a cubic crystal structure at room temperature. Therefore, sonochemical irradiation could accelerate the formation of BaZrO<inf>3</inf> particles significantly. Furthermore, scanning electron microscopy investigated the uniform shape and size. The size distribution became narrow with increasing time, as a function of irradiation. © 2013 Copyright Taylor and Francis Group, LLC.