Vittayakorn, Naratip

Preferred name

Alternative Name

Vittayakorn, N.

Vittayakorn, Narathip

Main Affiliation

School of Science

naratip.vi@kmitl.ac.th

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Synthesis, phase formation and characterization of Co4Nb 2O9 powders synthesized by solid-state reaction
(2008-12-01)
Chaiyo, N.
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Muanghlua, R.
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Ruangphanit, A.
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Vittayakorn, W. C.
;
Vittayakorn, N.
A corundum-type structure of cobalt niobate (Co<inf>4</inf>Nb 2O<inf>9</inf>) has been synthesized by a solid-state reaction. The formation of the Co<inf>4</inf>Nb<inf>2</inf>O<inf>9</inf> phase in the calcined powders was investigated as a function of calcination conditions by differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Morphology and particle size have been determined by scanning electron microscopy (SEM). It was found that the minor phases of unreacted Co <inf>3</inf>O<inf>4</inf> tend to form together with the columbite CoNb <inf>2</inf>O<inf>6</inf> phase at a low calcination temperature and short dwell time. It seems that the single-phase of Co<inf>4</inf>Nb<inf>2</inf>O <inf>9</inf> in a corundum phase can be obtained successfully at the calcination conditions of 900°C for 60 min, with heating/cooling rates of 20°C /min. © 2008 Trans Tech Publications, Switzerland.
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Ferroelectric phase stabilization, phase transformations and thermal properties in (1-x)PbZrO3-xPb(Co1/3Nb2/3)O 3 solid solution
(2008-11-01)
Banlue, Wanwimon
;
Vittayakorn, Naratip
The solid solution between the antiferroelectric PbZrO<inf>3</inf> (PZ) and relaxor ferroelectric Pb(Co<inf>1/3</inf>Nb<inf>2/3</inf>)O<inf>3</inf> (PCoN) was synthesized by the columbite method. The phase structure and thermal properties of (1-x)PZ-xPCoN, where x=0.0-0.3, were investigated. With these data, the ferroelectric phase diagram between PZ and PCoN has been established. The crystal structure data obtained from XRD indicates that the solid solution PZ-PCoN, where x=0.0-0.3, successively transforms from orthorhombic to rhombohedral symmetry with an increase in PCoN concentration. The AFE→FE phase transition was found in the compositions of 0.0 ≤ x ≤ 0.10. The AFE→FE phase transition shift to lower temperatures with higher compositions of x. The width of the temperature range of FE phase was increased with increasing amount of PCoN. It is apparent that the replacement of the Zr4+ ion by (Co<inf>1/3</inf>Nb<inf>2/3</inf>)4+ ions would decrease the driving force for antiparallel shift of Pb2+ ions, because they interrupt the translational symmetry. This interruption caused the appearance of a rhombohedral ferroelectric phase when the amount of PCoN was more than 10 mol%. © 2008 Springer-Verlag.
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Effect of calcination temperatures on microstructure and phase formation of Ba(Zr0.25Ti0.75)O3 powders
(2008-12-01)
Bongkarn, T.
;
Phungjitt, N.
;
Vittayakorn, N.
In this work, the effect of calcination temperatures on the microstructure and phase formation of Ba(Zr<inf>0.25</inf>Ti<inf>0.75</inf>)O<inf>3</inf> (BZT) powders were investigated. The BZT powders were prepared via the solid state reaction method under various calcination temperatures. It was found that the second phases such as BaCO<inf>3</inf> ZrO<inf>2</inf>, BaZrO<inf>3</inf> and Ba<inf>2</inf>ZrO<inf>4</inf> existed in samples with calcination temperature below 1200 °C. Homogeneity and a highly pure perovskite phase of the BZT powders were obtained with calcination condition at 1300 °C for 4 h. Lattice parameter a and the percentage of cubic perovskite phase tended to increase with increasing calcination temperatures. The TG-DTA results corresponded to the XRD investigation. The microstructures of calcined powders exhibited an almost-spherical morphology and had a porous agglomerated form in all samples. The average particle sizes were increased from 0.2 to 1.1 μm when calcination temperatures were increased from 800 to 1350 °C. © 2008 Trans Tech Publications, Switzerland.
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Phase transition and dielectric properties of lead free (K 0.5Na0.5)NbO3- Bi(Zn0.5Ti 0.5)O3 piezoelectric ceramics
(2009-12-01)
Sutapun, Manoon
;
Vittayakorn, Naratip
Lead-free piezoelectric ceramics of (1-x)(K0.5Na0.5) NbO3 - x(Bi(Zn0.5Ti0.5)O3; x = 0.00-0.30 were prepared via the two-stage mixed oxide fabrication technique. The crystal structure and ferroelectric phase transitions were studied by means of x-ray diffraction and thermal measurements. XRD results showed that a single-phase perovskite structurewas formed in the ceramics with x ≤ 0.25. For the ceramics with x = 0.30, a small amount of secondary phase Bi2Ti2O7 with a cubic structure was formed. The ceramics with a perovskite structure showed an orthorhombic phase at 0.00 ≤ x ≤ 0.010 and became rhombohedral at 0.010 < x ≤ 0.015 before transforming to a cubic phase at 0.015 < x ≤ 0.25. In addition, DSC results showed that the phase transition temperature of orthorhombic-tetragonal (TO-T) and tetragonal-cubic (TC) decreased when a small amount of BZT was added. The trend of enthalpy for orthorhombic → tetragonal phase transition and tetragonal → cubic phase were found to reduce with progressive increases in small amounts of BZT content. This behavior could originate from the more complex occupation of the A and B sites in an ABO3 perovskite structure. Copyright © Taylor & Francis Group, LLC.
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Structural transformation in antiferroelectric PbZrO3-relaxor ferroelectric Pb(Ni1/3 Nb2/3)O3 solid solution system
(2008-08-12)
Wirunchit, S.
;
Vittayakorn, N.
The solid solution between the antiferroelectric (AFE) PbZrO<inf>3</inf> (PZ) and the relaxor ferroelectric (FE) Pb (Ni<inf>1/3</inf>Nb <inf>2/3</inf>)O<inf>3</inf> (PNN) was synthesized by the columbite precursor method. The crystal structure, phase transformations, and dielectric and thermal properties of (1-x) PZ-xPNN where x=0.00-0.30 were investigated. With these data, the FE phase diagram between PZ and PNN has been established. The crystal structure data obtained from X-ray diffraction indicate that the solid solution PZ-PNN, where x=0.00-0.30, successively transforms from orthorhombic to rhombohedral symmetry with an increase in the PNN concentration. The AFE phase→FE phase transition occurs in compositions of 0.00≤x≤0.08. The AFE→FE phase transition shifts to lower temperatures with higher compositions of x. The FE phase temperature range width increases with increased PNN. Apparently the replacement of the Zr4+ ion by Ni 2+/Nb5+ ions decreases the driving force for an antiparallel shift of Pb2+ ions because they interrupt the translational symmetry and facilitates the appearance of a rhombohedral FE phase when the amount of PNN is higher than 8 mol %. © 2008 American Institute of Physics.
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Phase transition, mechanical, dielectric and piezoelectric properties of perovskite (Pb1-xBax)ZrO3 ceramics
(2007-01-01)
Vittayakorn, Naratip
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Bongkarn, Theerachai
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Rujijanagul, Gobwute
(Pb<inf>1-x</inf>Ba<inf>x</inf>)ZrO<inf>3</inf> ceramics were prepared in the composition range 0.00≤x≤0.30 by the mixed oxide solid-state reaction method. The samples were kept at the calcination temperature 1000 °C for 1 h and at the sintering temperature 1300 °C for 3 h. The structural phase transitions and the dielectric properties were studied. It was found that the density of the ceramics decreases with increasing amount of Ba2+, whilst the average grain size is in the range 1-2.3 μm. The structure of as-calcined powder reveals that the fraction of the orthorhombic phase is decreasing with increasing Ba2+ content. The values of Vickers and Knoop hardness are in the range of 4.10-6.48 and 4.15-5.67 GPa, respectively. Dielectric measurements show that the antiferroelectric phase (AFE)-ferroelectric phase (FE) and the FE to paraelectric phase (PE) phase transformation temperatures decrease with increasing Ba2+ concentration. The AFE-FE phase transformation is detected for compositions 0.00≤x≤0.075. The maximum dielectric constant gradually increases with increasing composition up to x=0.20. For higher Ba2+ concentrations, the lowering of the maximum dielectric value is accompanied by a progressive broadening of the permittivity peak. The d<inf>33</inf> values of the samples increase from ∼0 to 87 pC/N with increasing Ba2+ concentration from x=0.00 to 0.30. © 2006 Elsevier B.V. All rights reserved.
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Physical properties and phase transitions in perovskite Pb[Zr 1-x(Ni1/3Nb2/3)x]O3 (0.0 ≤ x ≤ 0.5) ceramics
(2008-06-21)
Wirunchit, Supamas
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Laoratanakul, Pitak
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Vittayakorn, Naratip
A solid solution of lead zirconate-lead nickel niobate ceramics, Pb[Zr <inf>1-x</inf>(Ni<inf>1/3</inf>Nb<inf>2/3</inf>)<inf>x</inf>]O<inf>3</inf> (PZNN) with x = 0.0-0.5, was synthesized via the columbite precursor method. The crystal structures as well as the thermal and dielectric properties were investigated in terms of the lead nickel niobate (PNN) concentration. X-ray diffraction indicated that all samples exhibited a single-phase perovskite structure. At room temperature, Pb[Zr<inf>1-x</inf>(Ni<inf>1/3</inf>Nb <inf>2/3</inf>)<inf>x</inf>]O<inf>3</inf> is orthorhombic for a composition where x = 0, rhombohedral for the compositions where x = 0.1, 0.2 and 0.3 and pseudo-cubic for compositions where x = 0.4 and 0.5. The results of the addition of lead nickel niobate to the lead zirconate ceramic showed enhancement of the room-temperature dielectric permittivity. Lead nickel niobate substitution also led to lower transition temperatures. Furthermore, this transition from normal to relaxor FE ceramics was typified by a quasi-linear relationship between the diffuseness parameter δ<inf>γ</inf> and the PNN mole fraction x. © 2008 IOP Publishing Ltd.
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High temperature phases in the 0.98 PbZrO3 -0.02Pb (Ni 1/3Nb2/3) O3 ceramic
(2009-07-09)
Qu, W.
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Tan, X.
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Vittayakorn, N.
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Wirunchit, S.
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Besser, M. F.
The phase evolution with temperature in the 0.98 PbZrO<inf>3</inf> -0.02Pb (Ni<inf>1/3</inf>Nb<inf>2/3</inf>) O<inf>3</inf> ceramic was investigated with dielectric permittivity and polarization measurements, hot stage transmission electron microscopy, and high temperature x-ray diffraction. Below 190 °C, the ceramic is in the antiferroelectric phase with characteristic 1 4 { 110 } c superlattice diffractions. In this stage, typical antiferroelectric 180° domains were observed. Between 190 and 220 °C, an intermediate phase, which is characterized by 1 2 { 110 } c -type superlattice diffractions, was detected. Evidences are found to suggest that this intermediate phase is ferroelectric. The 1 2 { 110 } c -type superlattice diffraction persists even into the paraelectric phase above 220 °C. In addition, there exists an incommensurate phase between the low temperature antiferroelectric phase and the intermediate ferroelectric phase. © 2009 American Institute of Physics.
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Synthesis and properties of Pb(Co1/3Nb2/3)O3 ceramics
(2008-10-20)
Unruan, Muangjai
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Vittayakorn, Naratip
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Wongmaneeruang, Rewadee
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Prasatkhetragarn, Anurak
;
Ananta, Supon
In this study, Pb(Co<inf>1/3</inf>Nb<inf>2/3</inf>)O<inf>3</inf> or PCN ceramics have been produced by sintering PCN powders synthesized from lead oxide (PbO) and cobalt niobate (CoNb<inf>2</inf>O<inf>6</inf>) with an effective method developed for minimizing the level of PbO loss during sintering. Attention has been focused on relationships between sintering conditions, phase formation, density, microstructural development, dielectric and ferroelectric properties of the sintered ceramics. The densities of sintered PCN ceramics increased with increasing sintering temperature. However, it was observed that at too high temperature the density began to decrease. Change of dielectric properties with sintering temperature also followed the same trend as the density. Based on X-ray diffraction analysis, density data, SEM micrograph, and dielectric properties, the optimum sintering temperature for a high purity PCN ceramic was found to be about 1100 and 1150 °C. A strongly diffused dielectric peak also showed a typical characteristic of ferroelectric relaxors. The P-E hysteresis loops observed at -70 °C were of slim-loop type with small remnant polarization values, which confirmed relaxor ferroelectric behavior of PCN ceramics. © 2007 Elsevier B.V. All rights reserved.
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Effect of annealing time on electrical and mechanical properties of 0.7(Pb(Zr1/2Ti1/2)O3) - 0.3(Pb(Zn 1/2Nb2/3)O3 ceramics
(2009-12-01)
Rujijanagul, G.
;
Vittayakorn, N.
;
Nabunmee, S.
The solid solution between the normal ferroelectric and relaxor ferroelectric of 0.7(Pb(Zr1/2Ti1/2)O3) - 0.3(Pb(Zn1/2Nb2/3)O3 was synthesized by the columbite method. After sintering, the ceramics were investigated as a function of annealing time. Properties of the ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), dielectric spectroscopy, and hardness tester. The results indicated that dielectric constant of the annealed samples was enhanced. In addition, hardness values of the annealed samples were also improved. Copyright © Taylor & Francis Group, LLC.

Vittayakorn, Naratip

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