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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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Wideband dielectric properties of silicon and glass substrates for terahertz integrated circuits and microsystems
(2021-05-01)
Chudpooti, Nonchanutt
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Duangrit, Nattapong
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Burnett, Andrew D.
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Freeman, Joshua R.
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Gill, Thomas B.
This paper presents a comprehensive study of the optical and electrical dielectric material properties of six commonly-used silicon and glass substrates at terahertz (THz) frequencies, including refractive index, absorption coefficient, dielectric constant and loss factor. The material characterization techniques used in this paper feature THz time-domain transmission and reflection spectroscopy with the measurement frequencies from 0.5 THz up to a maximum of 6.5 THz. Of the six selected dielectric and semiconductor substrates, two are silicon wafers with resistivities ranging from 0.001 to 0.02 Ω-cm. From the measurement results, loss tangents of the selected silicon wafers range from 0.680 to 5.455 and the dielectric constants are from 1.079 to 17.735. The four other wafers are all glass-based substrates: D263 glass, Borofloat 33 glass, fused silica and Sapphire. From the measurements, it is found that the THz dielectric properties vary considerably between the substrate samples e.g. dielectric constants range from 1.925 to 3.207 while loss tangents are from 0.042 × 10-3 to 0.127. Most of the selected silicon and glass-based substrates are quite useful for many THz applications, e.g., THz integrated circuits (THz ICs), THz microsystem technologies (THz MSTs) and THz system-on-a-chip (THz SoC) and system-on-substrate (SiP).
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Effect of Piezoelectric Phase on Electrical Properties of PDMS-Based Nanocomposites
(2021-01-01)
Kongjaiman, Patiparn
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Yunsamarn, Preedaporn
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Vittayakorn, Wanwilai
In this work, nanocomposite between polydimethylsiloxane (PDMS) and barium titanate (BT) are prepared in order to use as piezoelectric nanogenerator. Barium titanate phase with various amounts and shapes such as nanoparticles and nanowires are synthesized via appropriated methods. The PDMS and BT phases are homogeneously mixed and casted into 3 cm x 4 cm rectangle. Phase formation, chemical property and microstructure of these nanocomposites are identified via XRD, FTIR and SEM methods, respectively. Both frequency and temperature dependences of dielectric properties for all samples are measured by LCR meter. The piezoelectric properties of these nanocomposites are performed by study the generated output voltage and current after applying the mechanical force to the samples. From those results, it is concluded that the electrical properties of these BT/PDMS nanocomposites strongly depend on amounts and forms of piezoelectric filler. The orientation of polarization within the BT crystal shows an important role for piezoelectric properties of these nanocomposites.
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Utilization of Waste Glass Powder as a Filler in Epoxy Resin Based Composite
(2021-01-01)
Buaphuen, P.
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Khunna, D.
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Vittayakorn, W.
This work focuses on the preparation of a high-quality glass powder from broken household waste glass. The expected glass powder prepared from household waste must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The morphology of all glass powders was investigated by SEM. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 1 to 10 µm, and the 4 h-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder was rich in silica which contained about 67% of SiO<inf>2</inf>. After that, the various ratios of the glass powder/epoxy resin composites were formed by using the traditional casting method. The physical, mechanical and electrical properties were investigated for all composites. The results showed that the H<inf>v</inf> value of the glass powder/epoxy resin composites exhibited a much higher value than that of pure epoxy resin. For the electrical properties, after added 1 wt% of glass powder into the matrix, the ε<inf>r</inf> and R significantly increased. The E<inf>b</inf> value of the composite prepared from waste glass powder showed no significant difference from the composite prepared from commercial SiO<inf>2</inf>. So, it can say that the waste glass powder can be used as a filler in the epoxy resin-based composite as well as the commercial SiO<inf>2</inf> powder for the electrical insulting application.
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Dielectric, ferroelectric and piezoelectric properties of the lead free 0.9BaTiO3-(0.1- x)Bi0.5Na0.5TiO3- x Bi(Mg0.5Ti0.5)O3 solid solution
(2016-01-02)
Mayamae, Jitkasem
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Sukkha, Usa
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Niemchareon, Surasak
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Muanghlua, Rangson
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Vittayakorn, Naratip
Solid solution of 0.9BaTiO<inf>3</inf>-(0.1-x)Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>-xBi(Mg<inf>0.5</inf>Ti<inf>0.5</inf>)O<inf>3</inf> (BT-BNT-xBMT) system, where x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, was synthesized by the solid state reaction. Dense BT-BNT-xBMT ceramics were obtained by sintering at 1,150-1,250C for 4 h. The effect of BMT on crystal structure and electrical property of BT-BNT ceramics was investigated as a function of composition, x, using X-ray diffraction, dielectric spectroscopy, hysteresis and strain measurements. The crystal structure of solid solution BT-BNT-xBMT, where x = 0.00-0.10, successively transforms from tetragonal to pseudocubic symmetry, with increased BMT concentration. Temperature dependence of dielectric constant (ε<inf>r</inf>) and dielectric loss (tanδ) for BT-BNT-xBMT at various frequencies showed that phase transition of ceramics changed from ferroelectric to relaxor-like behavior as BMT content increased. Furthermore, remanent polarization (P<inf>r</inf>), coercive field (E<inf>c</inf>) and the normalized strain (d<inf>33</inf>∗) of BT-BNT-xBMT ceramics tend to decrease with increasing BMT concentration.
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The effect of firing temperatures on (Pb0.75Ba 0.25)(Zr0.70Ti0.30)O3 ceramics prepared via the combustion technique
(2013-12-01)
Sittiketkorn, Panadda
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Wongtey, Pongkiti
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Vittayakorn, Naratip
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Bongkarn, Theerachai
The (Pb0.7<inf>5</inf>Ba0.2<inf>5</inf>)(Zr<inf>0.70</inf>Ti <inf>0.30</inf>)O<inf>3</inf> (PBZT) ceramics were prepared via the combustion technique. (CO(NH<inf>2</inf>)<inf>2</inf>) was used as a fuel. The effect of firing temperature on PBZT's phase formation, microstructure and electrical properties were investigated. The calcination and sintering temperatures were 600°C-1000°C and 1100°C-1300°C. The pure rhombohedral perovskite was obtained from the powders calcined at 850°C. The average particle size tended to increase with increased calcination temperatures. A pure rhombohedral perovskite phase was found in all pellet samples. The average grain size and linear shrinkage tended to increase from 0.57 to 2.15 μm and from 6.8 to 15.8% with increased sintering temperatures. The dielectric results indicated the relaxer behavior of PBZT ceramics. The Curie temperature tended to decrease with increasing sintering temperatures. The highest density (∼7.39 g/cm 3) and highest dielectric constant (∼8620) were obtained by using the combustion technique which was higher than the conventional mixed oxide method. © 2013 Copyright Taylor and Francis Group, LLC.

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