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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
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Sookboon, Chirarat
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Somsri, Widchaya
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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.
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Modified energy storage properties of lead-free Sr0.3Bi0.35Na0.335Li0.015TiO3 ceramics with La3+ substitution via the solid-state combustion technique
(2024-12-01)
Sinkruason, Thanapon
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Luangpangai, Anupong
;
Julphunthong, Phongthorn
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Rittidech, Aurawan
;
Suthapintu, Aekasit
In this study, the influence of La3+ substitution on the phase structure, microstructure, electrical and energy storage properties of (Sr<inf>0.3</inf>Bi<inf>0.35</inf>Na<inf>0.335</inf>Li<inf>0.015</inf>)<inf>1-x</inf>La<inf>x</inf>TiO<inf>3</inf> (SBNLT-xLa) ceramics with x = 0–0.05, using the solid-state combustion technique, was investigated. X-ray diffraction (XRD) patterns indicated a pure perovskite structure formed, along with coexisting rhombohedral and tetragonal phases in all ceramics. The Rietveld refinement analysis showed the tetragonal phase increased while the rhombohedral phase decreased with increased La3+ content. The morphology of the SBNLT-xLa ceramics displayed polygonal grain shapes and anisotropic grain growth. Average grain sizes increased from 2.01 to 2.43 μm as x increased from 0 to 0.01 and afterwards decreased as x increased further. Both the measured density and maximum dielectric constant (ɛ<inf>m</inf>) decreased from 5.48 to 5.29 g/cm3 and from 4667 to 2313, respectively, when x increased from 0 to 0.05. A decrease in the dielectric properties caused by the phase ratio shifting away from a morphotropic phase boundary (MPB) condition, poor microstructure and low density was produced with La3+ replacement. The maximum polarization (P<inf>max</inf>), remnant polarization (P<inf>r</inf>) and coercive field (E<inf>c</inf>) decreased with increased La3+ content. A decline in P<inf>r</inf> and E<inf>c</inf> improved the energy storage efficiency (ƞ) and energy storage loss (W<inf>loss</inf>), resulting in enhanced energy storage properties. At x = 0.02, the ceramic showed good energy storage properties (W<inf>total</inf> of 0.781 J/cm3, W<inf>rec</inf> of 0.624 J/cm3, W<inf>loss</inf> of 0.157 J/cm3 and ƞ of 79.8%), measured at 60 kV/cm.
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Oxidation Kinetics of Soot on Acicular Mullite Membrane Filter Using Electron Microscopy and Thermogravimetric Analysis
(2020-12-01)
Saenkhumvong, Eakkawut
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Karin, Preechar
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Charoenphonphanich, Chinda
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Vittayakorn, Naratip
;
Hanamura, Katsunori
This paper investigates the oxidation kinetics of carbon black on acicular mullite using thermogravimetric (TGA) and mullite microstructures by scanning electron microscopy (SEM) for the development of diesel particulate filters (DPFs). It is observed that the amount of each chemical composition strongly affects the structure of mullite. The addition of AlF<inf>3</inf> and V<inf>2</inf>O<inf>5</inf> to mullite promotes the growth of needle-shaped mullite crystals. Thermogravimetric analysis was used to investigate and characterize chemical kinetics of soot oxidation for better understanding of designs and configurations of diesel particulate filters. The mass conversion of soot on the acicular mullite (ACM) is oxidized faster than that on the mullite (ML) membrane at all temperatures examined. The calculation of apparent activation energy (E<inf>a</inf>) of soot oxidation with isothermal methods on mullite was presented. The results showed that activation energy of soot oxidation is enhanced with ACM than with ML at all temperatures examined. The average calculated apparent activation energy of soot oxidation on ACM and ML are 146.4 kJ/mole and 155.3 kJ/mole, respectively.
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Effect of firing temperatures on phase formation and microstructure of Ba(Zr0.3Ti0.7)O3 ceramics prepared via mixed oxide method
(2009-12-01)
Bongkarn, Theerachai
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Phungjitt, Nalinee
;
Vittayakorn, Naratip
Ba(Zr0.3Ti0.7)O3 (BZT) ceramics were fabricated by a mixed oxide synthetic route. The effect of calcination and sintering temperatures on phase formation and the microstructure of the ceramics were investigated. The pure perovskite phase of BZT powders was obtained with a calcination condition of 1300°C for 4 h. The sintered pellets showed a pure peroverskite cubic phase in all samples. The microstructure of the powders exhibited an almost-spherical morphology and had a porous agglomerated form. The average particle sizes and the average grain sizes were increased from 0.2 to 1.1 μm and 3.9 to 25.1 μm with increasing calcination and sintering temperatures, respectively. The densest and the highest maximum dielectric constant was found in the BZT ceramic sintered at 1550°C. Copyright © Taylor & Francis Group, LLC.

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