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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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Multiferroic Properties of (1-x)BiFeO3-xBaTiO3 Lead-Free Ceramics
(2023-01-01)
Panpho, Phakakorn
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Intrirak, Kumaret
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Vittayakorn, Naratip
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Jantaratana, Pongsakorn
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Bongkarn, Theerachai
Lead-free (1-x)BiFeO<inf>3</inf>-xBaTiO<inf>3</inf> ceramics (abbreviated as BF-xBT), in a composition range of 0.23 ≤ x ≤ 0.33 mol%, were prepared by the conventional solid-state reaction method. The effect of x content on phase structure, microstructure, magnetic and electrical properties of BF-xBT ceramics is also investigated. With the incorporation of x content, the coexistence of rhombohedral and tetragonal phases was observed. Field emission scanning electron microscope (FESEM) micrographs revealed that the average grain size of BF-xBT ceramics first decreased and then increased with adding x content. The fracture surface of samples showed a mode of inter-granular fracture and intra-granular fracture. The ferroelectric properties were enhanced by adding x ≥ 0.29 mol% in the BF-xBT system. The dielectric and magnetic properties were improved with a maximum value are ε<inf>r</inf> = 888,711, M <inf>max</inf> = 0.40 emu/g, M <inf>r</inf> = 0.17 emu/g, and H <inf>c</inf> = 3.7 kOe at x = 0.25 mol%.
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Effect of Na+ Substitution on the Phase, Microstructure, Electrical and Energy Storage Properties of BSBZNT Ceramics Prepared by the Solid-State Combustion Technique
(2023-01-01)
Chongsatan, Wistsarut
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Didpim, Ratirom
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Julphunthong, Phongthorn
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Thatawong, Bhoowadol
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Vittayakorn, Naratip
(Ba<inf>0.704</inf>Sr<inf>0.176</inf>Bi<inf>0.12</inf>)<inf>1-x</inf>Zn<inf>0.08</inf>Nb<inf>0.04</inf>Ti<inf>0.88</inf>O<inf>3</inf>-Na<inf>x</inf> (BSBZNT-xNa) ceramics with x = 0, 0.01, 0.03 and 0.05 mol%, were prepared by the solid-state combustion technique. The samples were calcined and sintered at 950 °C and 1375 °C, respectively, for 2 h. The phase, microstructure, dielectric, ferroelectric and energy storage properties were investigated. The X-ray diffraction patterns of the BSBZNT-xNa powders showed a perovskite phase for all samples. When x increased from 0-0.03, the average particle size increased from 380 to 480 nm, then decreased to 420 nm. All sintered samples showed the coexistence of the orthorhombic and cubic phases. The average grain size was in the range of 2.03 to 1.39 µm. The BSBZNT-0.01Na ceramic exhibited the highest dielectric properties at room temperature (ɛ<inf>r</inf> = 902, tanδ = 0.10), the lowest remanent polarization (P <inf>r</inf> = 0.10 µC/cm2), coercive field (E <inf>c</inf> = 0.43 kV/cm), and the highest energy storage efficiency (η ∼ 94.70%) measured under an electric field of 70 kV/cm.
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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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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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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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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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Fabrication of new (Ba0.97Ca0.03)(Zr0.94Sn0.06)O3 ceramics by the combustion technique
(2016-01-26)
Mathrmool, Krailas
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Vittayakorn, Naratip
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Bongkarn, Theerachai
In this study, new (Ba<inf>0.97</inf>Ca<inf>0.03</inf>)(Zr<inf>0.94</inf>Sn<inf>0.06</inf>)O<inf>3</inf> BCZS ceramics were synthesized by the combustion technique using glycine as fuel. The powders and ceramics were calcined from 1,000 to 1,200 °C for 2 h and sintered from 1,500 to 1,675 °C for 2 h. A pure perovskite phase was found in the powder calcined at higher than 1,150 °C and the purity phase of the ceramics was detected in all samples. The average particle size and grain size increased approximately from 73 to 103 nm and from 0.51-1.61μm when firing temperatures increased. The calcined powders exhibited tight agglomerates at low calcination temperatures and they changed to loosely bound agglomerates at higher calcination temperatures. The densest ceramics were discovered in the samples sintered at 1,650 °C. The dielectric constant (ε<inf>r</inf>) and loss factor (tan δ) values measured at 100 kHz of this sample were found to be 44 and 0.01, respectively at room temperature.
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Low firing temperatures and high ferroelectric properties of (Ba0.85Ca0.15)(Ti 0.90Zr0.10)O3 lead-free ceramics synthesized by the combustion technique
(2016-01-26)
Kornphom, Chittakorn
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Vittayakorn, Naratip
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Bongkarn, Theerachai
This work studied the effect of firing conditions on phase formation, microstructure and electrical properties of (Ba<inf>0.85</inf>Ca<inf>0.15</inf>)(Ti<inf>0.90</inf>Zr<inf>0.10</inf>)O<inf>3</inf>;(abbreviated as BCTZ) ceramics, which were synthesized through the combustion technique. To reduce the reaction temperature, glycine was used as fuel with a ratio of raw material: glycine (1:1.11). BCTZ samples were calcined at 900-1200°C for 2 h and sintered at 1350 -1550°C for 2 h. Ultrafine BCTZ powder and single peroveskite phase were achieved from the sample calcined at 1050°C for 2 h.These results were obtained at a lower temperature and with shorter dwell time than those obtained using the solid state reaction method by ∼150°C and 1 h, respectively. The BCTZ ceramics exhibited a coexistence of rhombohedral and orthorhombic phase in all samples. The average particle size and the average grain size increased from 172 to 295 nm and 0.82 to 2.57 μm, respectively, when firing temperatures increased. The highest density (5.76 g/cm3), highest dielectric constant (ε<inf>r</inf> ≅ 4485 and ε<inf>max</inf> ≅ 14897) and best ferroelectric properties (P<inf>r</inf> ≅ 18.47 C/cm2 and E<inf>C</inf> ≅ 4.52 kV/cm) were obtained from the sample sintered at 1450°C for 2 h.

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