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Phase formation and electrical properties of SBNLT ceramics prepared via combustion technique
(2023-01-01)
Sinkruason, Thanapon
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Luangpangai, Anupong
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Charoenthai, Nipaphat
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Rittidech, Aurawan
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Pulphol, Phieraya
This report investigates the effect of firing temperatures on the phase formation, microstructure, electrical, and energy storage properties of lead-free Sr<inf>0.3</inf>(Bi<inf>0.7</inf>Na<inf>0.67</inf>Li<inf>0.03</inf>)<inf>0.5</inf>TiO<inf>3</inf> (SBNLT) ceramics, synthesised by combustion technique. The samples were calcined between 700°C and 900°C for 2 h and sintered between 1100°C and 1200°C for 2 h. The ceramics exhibited coexisting rhombohedral and tetragonal phases, which were confirmed by the Rietveld refinement technique. A morphotropic phase boundary (MPB) of the rhombohedral and tetragonal phases, with a ratio of 49:51, was obtained at the sintering temperature of 1175°C. The highest maximum dielectric constant (ε <inf>max</inf>= 4667), polarisation (P <inf>max</inf>= 28.80 µC/cm2) and energy density (W = 0.95 J/cm3), with a breakdown strength of 70 kV/cm, were achieved from the sample sintered at 1175°C.
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Enhancement of the Dielectric and Energy Storage Properties of Lead-Free BNSLT Ceramics by Zr4+ Substitution into B-Sites
(2023-01-01)
Luangpangai, Anupong
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Noiphoowiang, Nachtarika
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Premwichit, Pathit
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Klinbanmor, Metarsit
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Vittayakorn, Naratip
(Bi<inf>0.38</inf>Na<inf>0.30</inf>Sr<inf>0.28</inf>)<inf>0.98</inf>La<inf>0.02</inf>Ti<inf>1-x</inf>Zr<inf>x</inf>O<inf>3</inf> (abbreviated as BNSLT<inf>1-x</inf>Zr<inf>x</inf>, with x = 0 − 0.05) lead free ceramics were fabricated using the solid-state combustion method. The phase structure, microstructure and electrical properties of the ceramics were investigated. The coexistence of the rhombohedral (R) and tetragonal (T) phases was found in all samples. Rietveld refinement confirmed that as x increased from 0 to 0.05, the rhombohedral phase increased from 41 to 60%. A nearly equal R:T phase ratio of 49:51 was obtained for x = 0.01. All ceramics displayed polygonal grain shapes with anisotropic grain growth. The average grain size of the ceramics was in the range of 0.46–0.79 µm. The optimal Zr4+ content resulted in increased grain growth and reduced pores, leading to improved electrical properties. The highest density (5.52 g/cm3), maximum dielectric constant (ε <inf>m</inf> =2156), maximum polarization (P<inf>max</inf>=15.36 µC/cm2) and high energy storage properties (W<inf>total</inf>=0.49 J/cm3, W<inf>rec</inf>=0.45 J/cm3, W<inf>loss</inf>=0.05 J/cm3 and η = 90.54% at 60 kV/cm) were obtained from x = 0.01 caused by a morphotropic phase boundary (MPB) and good morphology.
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Fabrication of 0.7BaTiO3-0.3Ni0.7Zn0.3Fe2O4 Multiferroic Composite Ceramics Prepared by the Solid-State Combustion Technique
(2023-01-01)
Yimsabai, Sununta
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Warakham, Wichai
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Pinitsoontorn, Supree
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Vittayakorn, Naratip
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Bongkarn, Theerachai
Lead-free multiferroic composite ceramics of 0.7BaTiO<inf>3</inf>-0.3Ni<inf>0.7</inf>Zn<inf>0.3</inf>Fe<inf>2</inf>O<inf>4</inf> (BT-NZF) were prepared by the solid-state combustion technique. The BT and NZF powders were calcined in the range of 1100 to 1200 °C for 4 h and 900 to 1100 °C for 2 h, respectively. Afterward, BT-NZF composite ceramics were sintered between 1100 and 1250 °C for 4 h. The effect of the firing temperature on the phase formation, microstructure, electrical, and magnetic properties of BT-NZF composite ceramics was investigated. X-ray diffraction of BT and NFZ powders showed the highest purity phase were prepared the calcination temperatures of 1100 and 1050 °C, respectively. The BT-NZF composite ceramics exhibited coexisting tetragonal perovskite and cubic spinel phases. The maximum density of 5.85 g/cm3 was obtained when sintering the composite ceramics at 1125 °C. The dielectric constant at room temperature increased with increased sintering temperature. The hysteresis loops showed leakage current in all samples. Ferromagnetic properties showed the highest M<inf>s</inf> ∼ 24.56 emu/g measured under a magnetic field of 10,000 Oe from the sample sintered at 1150 °C.
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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
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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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Preparation of BST Powders and Ceramics via a Hybrid Method
(2023-01-01)
Klaytae, Thanawat
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Vittayakorn, Naratip
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Sumang, Rattiphorn
Barium strontium titanate (Ba<inf>0.8</inf>Sr<inf>0.2</inf>TiO<inf>3</inf>; BST) ceramics, were prepared by the hybrid method between Solid-state reaction (SSR) and Sol-gel methods (SG) in a ratio of 1:0.1–1:0.5. The BST powder was successfully calcined at 850 °C for 2 h. This temperature is much lower than the calcination temperatures of the SSR method. The BST ceramics were sintered between 1150 and 1450 °C. All samples showed the pure perovskite structure corresponding to JCPDS no. 34-0411. The optimum sintering temperature was observed from the samples sintered at 1450 °C for 4 h, indicating a density of 5.26 g/cm3, dielectric constant of 7018, and ferroelectric properties: (P <inf>max</inf> = 13.8 μC/cm2, P <inf>r</inf> = 2.5 μC/cm2 and E <inf>c</inf> = 2.3 kV/cm at 30 kV/cm).
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Phase Formation, Morphology and Electrical Properties of Lead-Free BNBLT-xBSN Ceramics Synthesized via the Solid-State Combustion Technique
(2023-01-01)
Thatawong, Bhoowadol
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Vittayakorn, Naratip
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Rittidech, Aurawan
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Bongkarn, Theerachai
Lead-free 1-x(Bi<inf>0.47</inf>Na<inf>0.47</inf>Ba<inf>0.06</inf>)<inf>0.95</inf>La<inf>0.05</inf>TiO<inf>3</inf>-xBa(Sn<inf>0.70</inf>Nb<inf>0.24</inf>)O<inf>3</inf> (BNBLT-xBSN) ceramics with x = 0, 0.01, 0.02, 0.03 and 0.04 mol.% were synthesized by the solid-state combustion technique with a calcination temperature of 750 °C for 2 h and a sintering temperature of 1150 °C for 2 h. The effect of BSN substitution on the phase formation, microstructure, dielectric, ferroelectric and energy storage properties of the BNBLT ceramics was investigated. With the substitution of BSN, the coexisting rhombohedral (R) and tetragonal (T) phases transformed into coexisting R and cubic (C) phase, verified by Rietveld refinement. The C phase increased with increased BSN content. The average grain size decreased from 1.14 to 0.89 µm when x increased to 0.03 and then increased to 0.96 µm. The measured density and maximum dielectric constant (ε <inf>m</inf>) tended to increase from 5.44 to 5.87 g/cm3 and 1800 to 1942 when x increased to 0.03, then decreased to 5.25 g/cm3 and 1501, respectively. The remanent polarization (P <inf>r</inf>) and coercive field (E <inf>c</inf>) decreased when x increased to 0.03. The 0.97BNBLT-0.03BSN ceramic exhibited the lowest energy loss density (W <inf>loss</inf> ∼ 0.10 J/cm3) and the highest energy-storage efficiency (η ∼ 77.3%) measured under an electric field of 70 kV/cm.
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Phase Structure, Microstructure, and Electrical Properties of Bi0.47Na0.47Ba0.06TiO3 Ceramics with (LiNb)4+ Substituted into B-Sites
(2023-01-01)
Luangpangai, Anupong
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Thatawong, Bhoowadol
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Charoenthai, Nipaphat
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Vittayakorn, Naratip
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Bongkarn, Theerachai
Due to the substitution of complex ions into B-sites is very interesting in recent, lead-free Bi<inf>0.47</inf>Na<inf>0.47</inf>Ba<inf>0.06</inf>Ti<inf>1−</inf><inf>x</inf> (LiNb) <inf>x</inf> O<inf>3</inf> (BNBT<inf>1−</inf><inf>x</inf> LN <inf>x</inf>) ceramics (with x = 0–0.04) were fabricated by the solid-state combustion method. The influence of (LiNb)4+ (x) on the phase structure, microstructure, and electrical properties was investigated. The X-ray diffraction (XRD) patterns exhibited a pure perovskite structure for all specimens. Coexisting rhombohedral and tetragonal phases were observed in all samples and the tetragonal phase increased with increased x, as analyzed by the Rietveld refinement method. The morphology of the BNBT<inf>1−</inf><inf>x</inf> LN <inf>x</inf> ceramics, obtained by scanning electron microscopy (SEM), revealed almost-round grain shapes and anisotropic grain growth. The density and average grain sizes decreased from 5.84 to 5.54 g/cm3 and 1.7 to 0.9 µm, respectively, when x increased from 0 to 0.04. The grain size distribution decreased with increased (LiNb)4+ content. A reduction in the dielectric properties was observed, due to the phase ratio changing away from a morphotropic phase boundary (MPB), an inferior microstructure, and low density caused by (LiNb)4+ substitution. The (LiNb)4+ substitution induced the transition from non-ergodic relaxor to ergodic relaxor ferroelectric state.
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Effect of Co2+ substitution in B-sites of the perovskite system on the phase formation, microstructure, electrical and magnetic properties of Bi0.5(Na0.68K0.22Li0.10)0.5TiO3 ceramics
(2022-09-01)
Bhupaijit, Pamornnarumol
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Kaewsai, Chonnarong
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Suriwong, Tawat
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Pinitsoontorn, Supree
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Yotthuan, Surirat
Bi<inf>0.5</inf>(Na<inf>0.68</inf>K<inf>0.22</inf>Li<inf>0.10</inf>)<inf>0.5</inf>Ti<inf>1−x</inf>Co<inf>x</inf>O<inf>3</inf> lead-free perovskite ceramics (BNKLT−xCo, x = 0, 0.005, 0.010, 0.015 and 0.020) were fabricated via the solid-state combustion technique. A small-amount of Co2+ ion substitution into Ti-sites led to modification of the phase formation, microstructure, electrical and magnetic properties of BNKLT ceramics. Coexisting rhombohedral and tetragonal phases were observed in all samples using the X-ray diffraction (XRD) technique. The Rietveld refinement revealed that the rhombohedral phase increased from 39% to 88% when x increased from 0 to 0.020. The average grain size increased when x increased. With increasing x, more oxygen vacancies were generated, leading to asymmetry in the bipolar strain (S−E) hysteresis loops. For the composition of x = 0.010, a high dielectric constant (ε<inf>m</inf>) of 5384 and a large strain (S<inf>max</inf>) of 0.23% with the normalized strain (d*<inf>33</inf>) of 460 pm·V−1 were achieved. The BNKLT−0Co ceramic showed diamagnetic behavior but all of the BNKLT−xCo ceramics exhibited paramagnetic behavior, measured at 50 K.
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Firing Temperature Effects on Phase Formation, Microstructure and Electrical Properties of BNKLT-Sm Ceramics
(2022-01-01)
Klinbanmor, Metarsit
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Bhupaijit, Pamornnarumol
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Charoonsuk, Thitirat
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Wanakamol, Panitan
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Vittayakorn, Naratip
Lead-free Bi<inf>0.5</inf>(Na<inf>0.68</inf>K<inf>0.22</inf>Li<inf>0.10</inf>)<inf>0.5</inf>TiO<inf>3</inf> + 0.003 mol Sm<inf>2</inf>O<inf>3</inf> (BNKLT-Sm) ceramics were synthesized via the solid-state combustion technique with calcination temperatures between 750 and 850 °C and sintering temperatures between 1025 and 1100 °C for 2 h. The results showed that increasing the calcination temperature caused the percentage of perovskite phase and the particle size of the BNKLT-Sm powders increased. The BNKLT-Sm powder calcined at 800 °C displayed a pure perovskite structure without any impurity phases. The influence of the sintering temperature on the phase formation, microstructure and electrical properties of the ceramics was then investigated. All samples sintered at different temperatures possessed coexisting rhombohedral (R) and tetragonal (T) phases and the R phase became dominant when the sintering temperature increased. The microstructure of all ceramics showed a rectangular shape and anisotropic growth. The average grain size increased with increasing sintering temperature. Dielectric and ferroelectric behavior displayed relaxor characteristics in all samples. The maximum dielectric constant at T<inf>m</inf> (ε<inf>m</inf>) of 4777 and the highest remnant polarization (P<inf>r</inf>) of 5.03 µC/cm2 were obtained by the densest ceramics (5.85 g/cm3), which was sintered at 1075 °C for 2 h.
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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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