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    Dielectric properties of nanocrystalline barium zirconate titanate synthesized by glycine-nitrate autocombustion
    (2019-01-02)
    Seeharaj, Panpailin
    ;
    Charoonsuk, Thitirat
    ;
    Vittayakorn, Naratip
    Dielectric properties of nanocrystalline barium zirconate titanate (Ba(Zr<inf>x</inf>Ti<inf>1-</inf><inf>x</inf>)O<inf>3</inf>; BZT for x = 0.1 and 0.3) synthesized by glycine-nitrate autocombustion method were investigated in this study. The phase formation examined by TGA-DTA, XRD, FT-IR and Raman spectroscopy confirmed that high purity single-phase BZT with perovskite structure was obtained by using glycine-to-nitrate molar ratio of 2.2:4 and calcining in air at 1100 °C for 4 h. TEM analysis showed that BZT had agglomerate particles consisted of primary spherical nanocrystals with the size of 8-11 nm. The diffuse phase transition behavior of BZT ceramics increased with increasing Zr concentration and for x = 0.3, the Curie temperature; T<inf>c</inf>, shifted to below room temperature. The BZT ceramics for x = 0.1 had relatively high dielectric constant (ε), 13007, low T<inf>c</inf>, 76 °C and comparable dielectric loss (tan δ) at T<inf>c</inf>, 0.012 which caused by the high degree of Zr diffuseness into the perovskite structure. These results suggest that glycine-nitrate autocombustion is the effective method for preparing high quality BZT ceramics.
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    Item type:Publication,
    Spherical nanocrystalline barium zirconate titanate prepared by Co-precipitation in highly basic aqueous solution
    (2013-01-01)
    Seeharaj, Panpailin
    ;
    Wirunchit, Supamas
    ;
    Charoonsuk, Piyanut
    ;
    Kim-Lohsoontorn, Pattaraporn
    ;
    Vittayakorn, Naratip
    Spherical monosized barium zirconate titanate nanoparticles (Ba(Zr <inf>x</inf>Ti<inf>1-x</inf>)O<inf>3</inf> (BZT) when x = 0.25, 0.30 and 0.35) have been prepared by co-precipitation in a strongly alkaline solution (20 M NaOH) at 80°C. The phase formation of the as-precipitated powders was characterized by XRD, FT-IR and Raman spectroscopy as a single-phase BZT with cubic perovskite oxide structure. This indicates that crystalline BZT powders can be obtained from the co-precipitation in 20 M NaOH without the requirement of calcination process. SEM analysis showed that BZT had nanosized spherical morphology with uniform shape and size. The crystal sizes obtained by TEM analysis were 20-40 nm. © 2013 Copyright Taylor and Francis Group, LLC.