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Author: search.filters.author.Somsri, WidchayaSubject: search.filters.subject.Microstructure

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    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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    ELECTRIC AND MAGNETIC PROPERTIES OF Ni0.475Zn0.475Li0.025Al0.025Fe2O4 DOPED (Bi0.5Na0.5)0.94Ba0.06TiO3 CERAMICS PREPARED BY THE SOLID-STATE COMBUSTION METHOD
    (2025-01-01)
    Pattanakasem, Wiwat
    ;
    Sookboon, Chirarat
    ;
    Somsri, Widchaya
    ;
    Vittayakorn, Naratip
    ;
    Pinitsoontorn, Supree
    In this study, we synthesized (1-x)((Bi<inf>0.5</inf>Na<inf>0.5</inf>)<inf>0.94</inf>Ba<inf>0.06</inf>TiO<inf>3</inf>)-x Ni<inf>0.475</inf>Zn<inf>0.475</inf>Li<inf>0.025</inf>Al<inf>0.025</inf>Fe<inf>2</inf>O<inf>4</inf> [(1-x)BNBT-xNZLAF] ceramics with x= 0, 0.05, 0.10, 0.15, and 0.20 using the solid-state combustion method. The phase formation, microstructure, and dielectric, ferroelectric, ferromagnetic, and magnetoelectric properties were investigated. BNBT and NZLAF powders were calcined at 750°C and 900°C for 2 h., respectively. The calcined powders were then mixed in various ratios to produce (1-x)BNBT-xNZLAF composites, which were sintered at 1125°C for 2 h. X-ray diffraction analysis indicated that undoped BNBT ceramics exhibited a typical perovskite structure with coexisting rhombohedral (R) and tetragonal (T) phases. With increasing NZLAF content, the cubic spinel (C) phase emerged with the R and T perovskite phases. Rietveld refinement indicated a higher percentage of the C phase as x increased. When x increased from 0 to 0.10, the average grain size and density increased (from 1.0 to 9.8 m and 5.45 to 5.61 g/cm3, respectively) followed by a drop at higher NZLAF levels. Doping BNBT ceramics with NZLAF resulted in a reduction in the dielectric constant (εr), dielectric loss (tan δ), and remnant polarization (Pr). The undoped BNBT ceramic showed a saturated P-E hysteresis loop, while NZLAF doped ceramics exhibited unsaturated P-E loops and increased leakage current. Magnetic measurements showed a transition from diamagnetic to ferromagnetic behavior with NZLAF doping. As x increased, the remnant magnetization (Mr), saturation magnetization (Ms), and magnetoelectric coefficient also increased (Mr0.058 emu/g, Ms3.594 emu/g, and MEcoefficient 2.64 mV/cm•Oe at x=0.25). These results suggest that NZLAF-doped BNBT ceramics hold potential for multiferroic material applications.