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EFFECT OF (AlNb)4+ B-SITES SUBSTITUTION ON THE PHASE STRUCTURE, MICROSTRUCTURE AND ELECTRICAL PROPERTIES OF Bi0.47Na0.47Ba0.06TiO3 CERAMICS
(2025-01-01)
Luangpangai, Anupong
;
Chongsatan, Wistsarut
;
Charoenthai, Nipaphat
;
Chootin, Suphornphun
;
Vittayakorn, Naratip
Bi0.47Na0.47Ba0.06Ti1-x(Al0.5Nb0.5)xO3 (abbreviated as BNBT1-xANx) lead-free ceramics (x=0-0.05) were synthesized by the solid-state combustion technique. The effect of (AlNb)4+ content on the phase structure, microstructure and electrical properties was investigated. A pure perovskite structure was obtained from all specimens. Rietveld refinement revealed coexisting rhombohedral and tetragonal phases in all samples and the tetragonal phase increased with increased AlNb content (x). The morphology of the BNBT1-xANx ceramics displayed nearly round grains and anisotropic grain growth. Average grain size decreased from 1.8 to 0.7 µm when x increased from 0 to 0.05 and the grain size distribution became narrower. The density, maximum dielectric constant and remnant polarization rapidly decreased with increased x. The deterioration of the electrical properties induced by (AlNb)4+ substitution was due to shifting away from the morphotropic phase boundary (MPB), poor microstructure and low density.
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PHASE FORMATION, MICROSTRUCTURE AND ELECTRIC PROPERTIES OF La3+ SUBSTITUTION IN B-SITE OF LEAD-FREE BaTi0.91Sn0.09O3 CERAMICS
(2025-01-01)
Pattanakasem, Wiwat
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Charoenthai, Nipaphat
;
Vittayakorn, Naratip
;
Thongyong, Nateeporn
;
Thongbai, Prasit
The study explored the influence of La3+ substitution at the B-site in BaTi0.91Sn0.09O3 (BTS) ceramics on their phase structure, microstructure, and electrical characteristics. La3+-doped BTS ceramics, denoted as Ba(Ti0.91Sn0.09)1-xLaxO3 (BTSL) with x = 0, 0.005, 0.010, 0.015, and 0.020, were synthesized via the conventional solid-state reaction method. The calcination and sintering processes were carried out at 1200°C for 2 hours and 1400–1450 °C for 4 hours, respectively. Results indicated that the undoped BTSL sample (x = 0) exhibited a pure perovskite phase without detectable impurities. However, when x ranged from 0.005 to 0.020, secondary impurity phases were observed alongside the perovskite structure. Phase analysis revealed that BTSL ceramics consisted of orthorhombic (O) and tetragonal (T) phases for x = 0–0.005, transitioned to a presence of O, T, and cubic (C) phases at x = 0.010–0.015, and exhibited only the C phase at x = 0.020. Rietveld refinement confirmed that La3+ occupied both A- and B-sites for compositions with x ≥ 0.005. As La3+ concentration increased, the average grain size and remnant polarization initially showed a slight reduction (x = 0 to 0.005) before significantly decreasing (x = 0.010 to 0.015). The Curie temperature (TC) was 43°C for x = 0, slightly increased to 44°C for x = 0.005, and then greatly decreased as x increased to 0.020.
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PHASE FORMATION AND ELECTRICAL PROPERTIES OF BCLTS CERAMICS SYNTHESIZED VIA THE SOLID-STATE COMBUSTION TECHNIQUE
(2025-01-01)
Somsri, Widchaya
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Charoenthai, Nipaphat
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Sutthapintu, Aekkasit
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Noisak, Jitrawan
;
Vittayakorn, Naratip
Lead-free Ba<inf>0.93</inf>Ca<inf>0.04</inf>La<inf>0.03</inf>Ti<inf>0.90</inf>Sn<inf>0.10</inf>O<inf>3</inf> (BCLTS) ceramics were fabricated via solid-state combustion technique. The BCLTS powders were calcined in a temperature range of 1075-1175°C for 2h and sintered in a temperature range of 1350-1450°C for 2h. The BCLTS powders exhibited a pure perovskite phase when calcined above 1150°C. All BCLTS ceramic samples displayed a perovskite structure with coexisting cubic and tetragonal phases, with a secondary phase observed only at 1450°C. The growth of grain size was increased with increasing sintering temperature (0.42 to 0.65 μm.). The highest dielectric and ferroelectric properties (ε<inf>r</inf>=3047, tan δ<inf>r</inf> = 0.029, P<inf>max</inf> = 9.52 μC/cm2, P<inf>r</inf> = 0.48 μC/cm2, E<inf>c</inf>= 1.04 kV/cm) were obtained at the sintering temperature of 1400°C. The altered phase structure in this research, compared to earlier studies, results in distinct outcomes for the dielectric and ferroelectric properties.
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EFFECT OF FIRING TEMPERATURE ON THE PHASE FORMATION, MICROSTRUCTURE, AND ELECTRICAL PROPERTIES OF BST-BZN CERAMICS
(2025-01-01)
Somsri, Widchaya
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Duangkeaw, Panadda
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Sumang, Rattiphorn
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Pulphol, Phieraya
;
Vittayakorn, Naratip
Lead-free 0.88Ba0.8Sr0.2TiO3-0.12Bi(Zn2/3Nb1/3)O3 (BST-BZN) ceramics were prepared by the solid-state combustion technique, using glycine as fuel. The BST-BZN ceramics were calcined between 900–1100°C for 2 h and sintered between 1300–1400°C for 2 h. A pure perovskite phase with a pseudo-cubic structure was observed by XRD and confirmed by the Rietveld refinement technique. The average particle and grain sizes tended to increase with increased calcination and sintering temperatures. The measured density was in the range of 5.65–5.90 g/cm3. The dielectric constant (εr) and dielectric loss (tan δr) decreased with increased sintering temperatures, up to 1350°C and then increased. The energy storage density (Wtotal) and energy storage efficiency (η) of the ceramics were 0.488 J/cm3 and 94.1% measured at 100 kV/cm, respectively, obtained by the sample sintered at 1375°C
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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
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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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