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    Item type:Publication,
    PHASE FORMATION AND ELECTRICAL PROPERTIES OF Ba0.91Ca0.09Ti0.916Sn0.084O3-0.1WT%ZnO -0.1WT%MnO2 LEAD-FREE FERROELECTRIC CERAMICS SYNTHESIZED VIA THE SOLID-STATE COMBUSTION METHOD
    (2025-01-01)
    Yimsabai, Sununta
    ;
    Somsri, Widchaya
    ;
    Vittayakorn, Naratip
    ;
    Charoenthai, Nipaphat
    ;
    Suthapintu, Aekasit
    This work investigated the effect of firing temperatures on the phase formation, microstructure, and electrical properties of Ba0.91Ca0.09Ti0.916Sn0.084O3-0.1wt%ZnO-0.1wt%MnO2 (BCTS-ZnMn) lead-free ferroelectric ceramics synthesized via the solid-state combustion method. Glycine was used as fuel to reduce the synthesis temperature. The samples were calcined at temperatures from 1050 to 1250°C (in 50°C increments) for 3 h and sintered from 1250 to 1450°C (in 50°C increments) for 3 h. A pure perovskite phase was found in the powders calcined above 1100°C. The phase structure, microstructure, dielectric and ferroelectric properties of the ceramics were examined. The X-ray diffraction (XRD) analysis for the ceramics revealed the presence of tetragonal (T) and orthorhombic (O) phases in all the ceramics. The average particle size and average grain size increased with increasing firing temperatures. The density, dielectric constant at the Curie temperature (ɛc), Pr and Ps tended to increase with increasing sintering temperatures, up to 1400°C, and then decreased at 1450°C. The ceramic sintered at 1400°C exhibited the highest density (5.89 g/cm3), dielectric response (ɛc = 13324) and good ferroelectric behavior (Pr = 8.67 μC/cm2, Ps = 17.92 μC/cm2 and Ec = 0.99 kV/cm).
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    Item type:Publication,
    Phase Formation, Microstructure and Electric Properties of Vanadium Doped Lead-Free BaTi0.91Sn0.09O3 Ceramics
    (2023-01-01)
    Pattanakasem, Wiwat
    ;
    Charoenthai, Nipaphat
    ;
    Vittayakorn, Naratip
    ;
    Bongkarn, Theerachai
    Lead-free Ba(Ti<inf>0.91</inf>Sn<inf>0.09</inf>)<inf>1-x</inf>V<inf>x</inf>O<inf>3</inf> (BTSV, x = 0, 0.005,0.010, 0.015, and 0.020) ceramics were prepared by the conventional solid-state sintering method with a calcination temperature of 1200 °C for 2 h and a sintering temperature between 1350 °C and 1400 °C for 4 h. The effect of vanadium (V) doping on the phase formation, microstructure and electrical properties of the ceramics was investigated. X-ray diffraction (XRD) measurements revealed that the ceramics with x = 0 and 0.005 had pure perovskite structures with no detectable impurity, while the ceramics with x ≥ 0.010 exhibited perovskite structures and had secondary impurity phases. Coexisting orthorhombic and tetragonal phases were observed and the Rietveld refinement analysis suggested that the tetragonal phase increased with increased V<sup>5+</sup> substitution. When x increased from 0 to 0.010, the average grain size increased from 47 to 62 µm and then dropped, while the density (ρ) decreased from 5.98 to 5.64 g/cm<sup>3</sup> when x increased. Furthermore, the BTSV ceramics exhibited increased porosity, Curie temperatures (T <inf>C</inf> ∼ 42 °C to 52 °C) and coercive field (E <inf>c</inf>), while the dielectric constant at the Curie temperature (ε<inf>C</inf>) and the remnant polarization (P <inf>r</inf>) of the ceramics decreased (∼18023 to 6110 and ∼7.42 to 4.88 µC/cm<sup>2</sup>, respectively) when V<sup>5+</sup> doping increased.