Vittayakorn, Naratip
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Vittayakorn, Naratip
Alternative Name
Vittayakorn, N.
Vittayakorn, Narathip
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naratip.vi@kmitl.ac.th
145 results
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Item type:Publication, Electrical properties of bismuth potassium titanate-strontium titanate ferroelectric ceramics(2010-07-30); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Rapid synthesis of potassium sodium niobate (K 1/2Na 1/ 2NbO3) lead-free piezoelectric powder using the combustion method(2013-12-01); ; ; Potassium sodium niobate (K1/<inf>2</inf>Na1/<inf>2</inf>NbO<inf>3</inf>) powder was synthesized successfully by the combustion synthesis. The raw materials of KNO<inf>3</inf>, NaNO<inf>3</inf> and Nb<inf>2</inf>O<inf>5</inf> were used with glycine as fuel. The thermal behaviour of the precursor was determined using thermo gravimetric analysis (TGA) and derivative thermo gravimetric (DTG) analysis. The conditions for preparing perovskite phase formation, influence of the fuel-to-oxidizer molar ratio, and crystal structure were characterized by the X-ray diffraction technique (XRD) and Fourier transform infrared (FTIR) spectroscopy. The morphology and particle size were investigated through a scanning electron microscope (SEM). © 2013 Copyright Taylor and Francis Group, LLC. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Fabrication of new (Ba0.97Ca0.03)(Zr0.94Sn0.06)O3 ceramics by the combustion technique(2016-01-26); Bongkarn, TheerachaiIn 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A rapid synthesis of cobalt cyclotetraphosphate Co2P 4O12 at low temperature(2013-05-01); The cobalt cyclotetraphosphate, Co<inf>2</inf>P<inf>4</inf>O<inf>12,</inf> was synthesized by evaporating a mixture of cobalt chloride hexahydrate, phosphoric acid and water at 70 °C, with further calcinations at 400 °C, 500 °C and 600 °C for 3 h. XRD results indicated that the Co <inf>2</inf>P<inf>4</inf>O<inf>12</inf> compounds obtained had only monoclinic phase with space group C<inf>2h</inf><sup>6</sup> (Z=4). From FT-IR spectra, vibrational modes corresponding to internal vibrations of the P <inf>4</inf>O<inf>12</inf><sup>4-</sup> anion were identified. The morphologies and crystallite sizes for the Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> obtained from SEM data and X-ray line broadening showed non-uniform particles and 37-68 nm, respectively. All characterization methods showed that the monoclinic phase of Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> could be synthesized at the low temperature of 400 °C with short time consumption. The temperature was about 400 °C lower than that used in the previous synthesis method with CoCl <inf>2</inf> as reactant, and resulted in a cost-, energy-, and time-saving method. © 2012 Elsevier Ltd and Techna Group S.r.l. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Phase formation and evolution of Cu:Zn partials in binary metal pyrophosphates Cu(2-x)Zn(x)P2O7; X ≈ 1(2014-11-20) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Spin-flop driven magneto-dielectric effect in Co4Nb 2O9(2011-09-26) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Electrical conductivity, magnetism, and optical properties of reduced BaCeO 3(2019-03-01); ; Kolodiazhnyi, TarasBaCeO <inf>3</inf> -based perovskites are well-known proton and oxygen ion conductors. For practical applications as electrolytes in solid oxide fuel cells, these compounds must be robust towards reduction of cerium ion. In this work, we explore the effect of reducing atmosphere on the physical properties of undoped and Nb-doped BaCeO <inf>3</inf> . The BaCeO <inf>3</inf> perovskite structure is thermodynamically stable at least up to 1450 <sup>∘</sup> C upon annealing in H <inf>2</inf> -containing atmosphere. Annealing at 1550 <sup>∘</sup> C causes a decomposition of the BaCeO <inf>3</inf> . The higher annealing temperature leads to higher concentration of Ce <sup>3 +</sup> ions and a higher electrical conductivity. With increasing the annealing temperature from 1300 to 1450 <sup>∘</sup> C , the activation energy of conductivity decreases from E <inf>a</inf> = 0.31–0.263 eV. We attribute the electrical conductivity in reduced BaCeO <inf>3</inf> to the activation of the small polaron hopping in agreement with the recent first-principles calculations. However, in contrast to the theoretical predictions, we find no evidence of the Ce <sup>3 +</sup> –Ce <sup>3 +</sup> spin-singlet small bipolarons. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Characterization and properties of BaTi3O3/MgO nanocomposite ceramics(2011-12-19); In this research, BaTiO<inf>3</inf>./xMgO nanocomposite ceramics, where x = 0, 0.3, 0.5, 0.7 and 1.0 vol%, were prepared by a mixedoxide method. The effect of MgO additions on the phase formation, microstructure and dielectric properties of this system was investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM) and dielectric spectroscopy, respectively. From the results, XRD analysis showed that there is no unwanted phase except BaTiO <inf>3</inf> and MgO observed in these ceramics. Abnormal grain growth was found in pure BaTiO<inf>3</inf> ceramic with a 75.32 μm average grain size. After adding MgO nanoparticles into the system, the grain size significantly decreased to 0.55 μm and continuously decreased with increasing MgO content. For the dielectric properties, the pure BT ceramic exhibits a sharp and high dielectric peak whereas a low and broad peak is found in BT/MgO nanocomposite ceramics, which can be explained by the composite structure. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Electrical and dielectric properties of barium titanate–polydimethylsiloxane nanocomposite with 0-3 connectivity modified with carbon nanotube (CNT)(2019-01-02); This study explored the preparation and electrical properties of 0–3 barium titanate/polydimethylsiloxane nanocomposites by dispersing barium titanate nanoparticles (BaTiO<inf>3</inf>; BT) into the polydimethylsiloxane (PDMS) matrix phase. The effect of barium titanate nanoparticles on electrical properties has been investigated systematically, and the relative permittivity of nanocomposites was found to increase significantly with increasing barium titanate content. Different theoretical models were used to predict the dielectric constant of these composites and compare their experimental value with the theoretical value in order to find an appropriate equation. The result indicated that the dielectric properties of composites are influenced not only by relative permittivity of the components but also dependence on interactions between ceramics and polymers. Furthermore, the preparation and dielectric properties of BT/PDMS nanocomposites modified with carbon nanotube (CNT) were also studied. The dielectric results demonstrate that adding CNT can enhance the relative permittivity of the BT/PDMS composite via improvement of dispersion and distribution of the BT nanoparticles in the PDMS matrix phase. Moreover, the electrical outputs from the BT/PDMS/CNT nanocomposites generator were measured under periodic knocking. The nanocomposites innovatively expand the feasibility of self-powered energy systems for smart sensor and energy harvesting applications. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study on thermal transformation of CuHPO4.H2O obtained by acetone-mediated synthesis at ambient temperature(2012-11-01); Copper hydrogenphosphate monohydrate, Cu- HPO<inf>4</inf>.H<inf>2</inf>O, was synthesized for the first time through simple and rapid method using the mixing of copper carbonate and phosphoric acid in acetone medium at ambient temperature. The obtained CuHPO<inf>4</inf>.H<inf>2</inf>O decomposed in three stages via dehydration and deprotonated hydrogenphosphate reactions, revealed by TG/DTG and DSC techniques. The kinetic triplet parameters (E<inf>a</inf>, A, and n) and thermodynamic functions (δHz.ast;, δGz.ast;, and δS*) for the first two decomposed steps were calculated from DSC data. All the obtained functions indicate that the deprotonated HPO<inf>4</inf> <sup>2-</sup> reaction for the second step occurs at a higher energy pathway than the dehydration reaction for the first step. The calculated wavenumbers based on DSC peaks were comparable with FTIR results, which support the breaking bonds of OH (H<inf>2</inf>O) and P-OH (HPO<inf>4</inf> <sup>2-</sup>) according to decomposed mechanisms. All the calculated results are consistent and in good agreement with Cu- HPO<inf>4</inf>.H<inf>2</inf>O's thermal transformation mechanisms. © Akademiai Kiado, Budapest, Hungary 2012.