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The modification of surface, size and shape of barium zirconate powder via salt flux
(2019-01-01)
Charoonsuk, Thitirat
;
Kolodiazhnyi, Taras
;
Vittayakorn, Naratip
The “top-down” process via direct conversion of the micro (μm)-to-submicroscale (sub-μm) particle was applied in this work by using eutectic chloride salts to prepare BaZrO<inf>3</inf>. The particle size at optimum condition could be decreased by more than 10 times from 2.1 ± 0.9 μm to 168 ± 23 nm without destroying the 1:1 of Ba:Zr stoichiometry. The uniform sub-μm-BaZrO<inf>3</inf> powder was sintered in order to obtain ~98% dense ceramic at 1400°C/10 h, which is significantly lower than the 1650°C in normal cases. The microwave dielectric constant, tan δ, and quality factor were also determined. Furthermore, this method also was applied to lead-free piezoelectric material in the 0.87BaTiO<inf>3</inf>–0.13BaZrO<inf>3</inf>–CaTiO<inf>3</inf>(0.87BT–0.13BZ–CT) system. The particle size of 0.87BT–0.13BZ–CT was reduced greatly from >10 µm to 2.8 ± 0.4 µm. It can be proved that salt flux dissolution method enables high-purity with uniform sub-micro/nanometer powder production in one step by using simple laboratory equipment and low-cost raw materials.
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BaZr0.3Ti0.7O3 nanoparticles synthesized by glycine-nitrate autocombustion
(2013-01-01)
Seeharaj, Panpailin
;
Charoonsuk, Piyanut
;
Kim-Lohsoontorn, Pattaraporn
;
Vittayakorn, Naratip
BaZr<inf>0.3</inf>Ti<inf>0.7</inf>O<inf>3</inf> (BZT) nanoparticles were prepared by glycine-nitrate autocombustion method. The effects of synthesis condition and calcination temperature on phase formation and microstructure of the BZT were investigated. XRD and FT-IR study indicated that BZT with cubic perovskite-type structure can be obtained from the synthesis condition using glycine-to-nitrate molar ratio of 2:3 and calcined in air at 1000°C for 4 h. The microstructure examined by SEM and TEM showed that BZT had agglomerate particles consisted of primary spherical nanocrystals with the crystallite sizes of 8-20 nm. © 2013 Copyright Taylor and Francis Group, LLC.
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Sonochemical synthesis of spherical BaTiO3 nanoparticles
(2013-01-01)
Vuttivong, Sirajit
;
Niemcharoen, Surasak
;
Seeharaj, Panpailin
;
Vittayakorn, Wanwilai C.
;
Vittayakorn, Naratip
Monosized spherical barium titanate (BaTiO<inf>3</inf>) nanoparticles have been synthesized successfully via sonochemical reaction. The as-synthesized BaTiO<inf>3</inf> nanoparticles were characterized using X-ray diffraction of powder, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The XRD pattern of BaTiO<inf>3</inf> particles, which were synthesized under irradiation of ultrasonic sound for 0.5 h, showed sharp diffraction peaks that corresponded to the cubic BaTiO<inf>3</inf> phase. Only a small amount of BaCO<inf>3</inf> contamination was present in the sample. The Raman active modes of the samples in this study were similar to the cubic phase of BaTiO<inf>3</inf>. The average diameter of sonochemical synthesized particles was ∼99.54 ± 18.25 nm. The synthesized BaTiO<inf>3</inf> nanoparticles were almost spherical. © 2013 Copyright Taylor and Francis Group, LLC.
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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.

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