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Phase Formation, Microstructure and Electric Properties of Vanadium Doped Lead-Free BaTi0.91Sn0.09O3 Ceramics
(2023-01-01)
Pattanakasem, Wiwat
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Charoenthai, Nipaphat
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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 V5+ 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/cm3 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/cm2, respectively) when V5+ doping increased.
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Classical to Relaxor Ferroelectric Transformation of Lanthanum Modified BaTi0.91Sn0.09O3 Ceramics
(2023-01-01)
Pattanakasem, Wiwat
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Prasertpalichat, Sasipohn
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Premwichit, Pathit
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Vittayakorn, Naratip
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Bongkarn, Theerachai
Lead-free Ba<inf>1-x</inf>La<inf>x</inf>Ti<inf>0.91</inf>Sn<inf>0.09</inf>O<inf>3</inf> (BLTS) ceramics with x = 0, 0.01, 0.03 and 0.05, were prepared by the traditional solid-state sintering method with calcination and sintering temperatures of 1200 °C for 2 h and 1400 °C for 4 h, respectively. X-ray diffraction (XRD) measurements revealed that all the BLTS ceramics had pure perovskite structures with no detectable impurities. When x = 0 and 0.01, the ceramics exhibited coexisting orthorhombic (O) and tetragonal (T) phases, while the orthorhombic (O), tetragonal (T) and cubic phase (C) were detected in the BLTS ceramics with x = 0.03 and 0.05, which the Rietveld refinement analysis confirmed. Furthermore, increasing x in the BLTS ceramics led to a large decrease in the average grain size (from 45.7 to 0.9 µm). A significant decrease in the remnant polarization (P <inf>r</inf>) accompanied by very slim hysteresis loops were observed for higher La (x ≥ 0.03) levels. This demonstrates that BLTS ceramics transition from classical ferroelectric to relaxor ferroelectric behavior due to changing occupancy of the A-site to La3+ from Ba2+.
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Sintering Temperature Effect on Phase Formation, Microstructure and Electrical Properties of Modified KNLNTS Solid Solution Prepared via the Solid-State Combustion Technique
(2023-01-01)
Kornphom, Chittakorn
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Thawong, Pichittra
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Khiwoon, Suprakorn
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Vittayakorn, Naratip
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Bongkarn, Theerachai
In this study, the effect of sintering temperature (1000–1100 °C for 2 h) on phase formation, phase transition, microstructure and electrical properties of lead-free piezoelectric (K<inf>0.44</inf>Na<inf>0.52</inf>Li<inf>0.04</inf>)(Nb<inf>0.84</inf>Ta<inf>0.10</inf>Sb<inf>0.06</inf>)O<inf>3</inf> (KNLNTS) solid solution with 0.3 wt%Bi<inf>2</inf>O<inf>3</inf> + 0.4 wt%Fe<inf>2</inf>O<inf>3</inf> + 0.2 wt%CuO additive (abbreviate as modified KNLNTS) was investigated. Modified KNLNTS ceramics were synthesized by the solid-state combustion technique using glycine as fuel. The modified KNLNTS powders were prepared using the calcination condition of 650 °C for 2 h. The XRD pattern of all sintered ceramics exhibited a pure perovskite phase. Using Rietveld refinement to analyze the phase formation showed that the modified KNLNTS ceramics had co-existing phases of orthorhombic and tetragonal in all sintered ceramics and the orthorhombic phase increased when the sintering temperature increased. The average grain size, T<inf>O-T</inf>, T<inf>c</inf>, P<inf>r</inf> and Ec increased with increasing sintering temperature. At the sintering temperature of 1025 °C, the modified KNLNTS ceramic showed the best electrical properties (C<inf>ε</inf> ≈ 6745, S<inf>max</inf> ≈0.274% and d*<inf>33</inf> ≈ 548 pm/V). The good electrical properties of the modified KNLNTS ceramics makes them good candidates for lead-free applications to replace Pb-based ceramics.
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Effect of the Firing Temperatures on the Phase Evolution and Electrical Properties of 0.85[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-0.15[Na0.73Bi0.09NbO3] Ceramics Synthesized via the Solid-State Combustion Method
(2023-01-01)
Pattanakasem, Wiwat
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Yotthuan, Surirat
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Hongsamsibjed, Pakornkiat
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Suriwong, Tawat
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Prasertpalichat, Sasipohn
In this research paper, we describe 0.85[0.94Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>-0.06BaTiO<inf>3</inf>]-0.15[Na<inf>0.73</inf>Bi<inf>0.09</inf>NbO<inf>3</inf>] (BNT-BT-NBN) ceramics fabricated by the solid-state combustion technique. The phase evolution, microstructure, dielectric, ferroelectric and energy storage properties were examined. The BNT-BT-NBN powders and ceramics were calcined and sintered between 650–900 °C and 1100–1175 °C, respectively, for 2 h. All samples showed a typical perovskite structure, as revealed by X-ray diffraction. The Rietveld refinement analysis of the ceramics suggested the samples sintered between 1100 and 1150 °C had coexisting R + T phases, while the R + T+C phases were observed in the ceramics sintered at 1175 °C. The average grain size of the samples increased from 0.52 to 1.39 μm with increased sintering temperature. The density of the ceramics increased from 5.12 to 5.45 g/cm3 when the sintering temperature increased from 1100 to 1150 °C, and then decreased. Increasing the sintering temperature from 1100 to 1150 °C caused the dielectric constant at T <inf>s</inf> (ε <inf>s</inf>) and the dielectric constant at T <inf>m</inf> (ε <inf>m</inf>) to increase from 1727 to 1945 and 1564 to 1750, respectively, and then ε <inf>s</inf> and ε <inf>m</inf> declined. All BNT-BT-NBN ceramics had good dielectric temperature stability with only a±10% change when the temperature ranged from room temperature to ∼300 °C. The optimum energy-storage properties (W <inf>rec</inf> = 0.62 J/cm3 and η = 83.2%) were obtained from the BNT-BT-NBN ceramics sintered at 1150 °C for 2 h. This data indicates that BNT-BT-NBN ceramics can be useful as lead-free materials for high density energy-storage capacitors.
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Phase evolution, microstructure and electrical response of KNNT ceramics with Li+ substitution and doping
(2022-01-01)
Yotthuan, Surirat
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Udeye, Thanya
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Prasertpalichat, Sasiphon
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Pulphol, Phieraya
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Vittayakorn, Naratip
Lead-free (K<inf>0.5</inf>Na<inf>0.5</inf>)(Nb<inf>0.7</inf>Ta<inf>0.3</inf>)O<inf>3</inf> (KNNT) ceramics with Li+ substitution (KN<inf>0.5-x</inf>Li<inf>x</inf>NT) and direct (KNNT-xLi) doping at x = 0, 0.01, 0.02, 0.03 and 0.04 mol% were synthesized by the solid-state combustion route. The phase, microstructure, dielectric and ferroelectric properties of the ceramics were examined. The XRD pattern of the ceramics revealed orthorhombic and tetragonal phases in all specimens. The Rietveld refinement procedure showed that increasing either the Li+ substitution or doping levels enhanced the amount of the tetragonal phase. It was found that Li+ doping, either substitutional or additional, enhanced the Curie temperature (T <inf>C</inf>) by increasing the tetragonal distortion, while the dielectric constant (ε <inf>C</inf>) decreased. The good remanent P-E loops of the KN<inf>0.5-x</inf>Li<inf>x</inf>NT ceramics were found with x = 0.01 (P <inf>r</inf>∼10.89 µC/cm2 and E <inf>C</inf>∼13.09 kV/cm), while for KNNT-xLi ceramics, it was obtained with x = 0.02 (P <inf>r</inf>∼15.65 µC/cm2 and E <inf>C</inf>∼11.46 kV/cm), which were confirmed by remanent P-E hysteresis measurements.
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Effect of substitution of (NiNb)4+ into B-sites on the phase formation, microstructure and electrical properties of Bi0.47Na0.47Ba0.06TiO3 ceramics
(2022-01-01)
Luangpangai, Anupong
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Bhupaijit, Pamornnarumol
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Charoenthai, Nipaphat
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Vittayakorn, Naratip
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Thountom, Sarawut
Bi<inf>0.47</inf>Na<inf>0.47</inf>Ba<inf>0.06</inf>Ti<inf>1-x</inf>(Ni<inf>1/3</inf>Nb<inf>2/3</inf>)<inf>x</inf>O<inf>3</inf> ceramics (abbreviated as BNBT<inf>1-x</inf>(NN)<inf>x</inf>, x = 0, 0.01, 0.03 and 0.05) were synthesized by solid-state combustion. The effect of x on the phase formation, microstructure and electrical properties of BNBT<inf>1-x</inf>(NN)<inf>x</inf> ceramics was examined. The XRD pattern indicated the coexistence of rhombohedral and tetragonal phases in all the specimens. Moreover, Rietveld refinement confirmed that the tetragonal phase increased from 47 to 71% when x increased from 0 to 0.05. The morphology of BNBT<inf>1-x</inf>(NN)<inf>x</inf> ceramics was observed by SEM and the ceramics grains showed polygonal shapes and the grain growth tended to be anisotropic. With (NiNb)4+ substitution, the average grain sized decreased rapidly from 1.7 to 1.0 µm and the grain size distribution was narrower as the amount of (NiNb)4+ increased. The density, remnant polarization (P<inf>r</inf>) and coercive field (E<inf>c</inf>) rapidly decreased with increasing x. A significant decrease in the ferroelectric properties was caused by the increasing tetragonal phase.
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The influences of Cs+ substitution and direct doping on the phase evolution, microstructure and electrical properties of KNNT ceramics
(2021-01-01)
Yotthuan, Surirat
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Udeye, Thanya
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Vittayakorn, Naratip
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Eitssayeam, Sukum
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Pulphol, Phieraya
The effects of Cs+ substitution and direct doping in (K<inf>0.5</inf>Na<inf>0.5</inf>)(Nb<inf>0.7</inf>Ta<inf>0.3</inf>)O<inf>3</inf> (KNNT) ceramics, on the crystal structure, microstructure and electrical properties were investigated. Both the KNNT with Cs+ substitution (K<inf>0.5-x</inf>Cs<inf>x</inf>NNT) and addition (KNNT-xCs) (x = 0, 0.01, 0.02, 0.03 and 0.04 mol%) were synthesized by the solid-state combustion technique using glycine as fuel. All samples were sintered at 1130–1150 °C for 4 h. The x-ray diffraction (XRD) analysis for the ceramics revealed the presence of orthorhombic (O) and tetragonal (T) phases in all samples. Increasing both the Cs+ substitution and doping amounts, enhanced the content of orthorhombic phase, as verified by the Rietveld refinement technique. It was found that Cs+ doping, either substitutional or additional, strongly decreased their density, dielectric and ferroelectric properties. The undoped KNNT ceramic exhibited well-saturated P-E hysteresis loop. With Cs+ doping, the samples became unsaturated and a leakage current was produced. The KNNT-xCs ceramics demonstrated higher density and dielectric properties than the K<inf>0.5-x</inf>Cs<inf>x</inf>NNT ceramics.
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The study of trivalent-dopants effect on electrical properties of the BaZr0.7In0.3O3-δ system
(2019-01-02)
Poolphol, Phieraya
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Muanghlua, Rangson
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Atiwongsangthong, Narin
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Vittayakorn, Wanwilai
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Vittayakorn, Naratip
Perovskite BaZrO<inf>3</inf> and BaZr<inf>0.7</inf>In<inf>0.3</inf>O<inf>3-δ</inf> (BZI) ceramics were prepared via solid-state reaction. The crystal structure, dielectric and electrical properties of these ceramics were analyzed comparatively. Rietveld analysis indicated that BaZrO<inf>3</inf> and BaZr<inf>0.7</inf>In<inf>0.3</inf>O<inf>3-δ</inf> (BZI) have cubic symmetry with the Pm (Formula presented.) m space group. A small amount of In<inf>2</inf>O<inf>3</inf> was observed in the BZI ceramic. The lattice parameter (a) decreased when a small amount of In3+ was added. The relative permittivity ε<inf>r</inf>(T) and tan δ(T) of BZ and BZI ceramics behaved as plateaus that were independent of frequency and temperature in a temperature range of below 150 ̊C and 50 ̊C, respectively, which ascribed to the intrinsic dielectric properties resulting from electronic and/or ionic polarization. By increasing the temperature further, both ceramics exhibited colossal dielectric constant (CDC) behavior. Conductivity was greater with increasing temperature, which corresponded to Arrhenius behavior. Activation energies were calculated as 0.522 and 0.620 eV for the BZI and BZ system, respectively.

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