KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 7 of 7

Some of the metrics are blocked by your
consent settings
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
;
Kaewsai, Chonnarong
;
Suriwong, Tawat
;
Pinitsoontorn, Supree
;
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.
Some of the metrics are blocked by your
consent settings
Firing Temperature Effects on Phase Formation, Microstructure and Electrical Properties of BNKLT-Sm Ceramics
(2022-01-01)
Klinbanmor, Metarsit
;
Bhupaijit, Pamornnarumol
;
Charoonsuk, Thitirat
;
Wanakamol, Panitan
;
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.
Some of the metrics are blocked by your
consent settings
Phase formation, microstructure and electrical properties of Ba0.9Ca0.1TiO3 ceramics fabricated via the solid-state combustion technique
(2022-01-01)
Sonchaopri, Nutkamon
;
Bhupaijit, Pamornnarumol
;
Yotthuan, Surirat
;
Sinkruason, Thanapon
;
Premwichit, Pathit
In this research, the effects of calcination temperature in a range of 1050–1200 °C for 2 h and sintering temperature in a range of 1325-1400 °C for 2 h on phase formation, microstructure and electrical properties of lead-free Ba<inf>0.9</inf>Ca<inf>0.1</inf>TiO<inf>3</inf> (BCT) ceramics fabricated via the solid-state combustion technique were investigated. For the XRD result, all the ceramics exhibited a coexisting phase between tetragonal and orthorhombic. The ceramic grain size tended to increase with increase of the sintering temperature. For BCT ceramic produced by the optimum sintering temperature (1375 °C for 2 h), the dielectric, ferroelectric and piezoelectric properties of ε <inf>C</inf>=7393, P <inf>r</inf>=7.60 μC/cm2<inf>,</inf> E <inf>C</inf>=5.99 kV/cm and d <inf>33</inf>=158 pC/N, respectively, were obtained.
Some of the metrics are blocked by your
consent settings
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
;
Bhupaijit, Pamornnarumol
;
Charoenthai, Nipaphat
;
Vittayakorn, Naratip
;
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.
Some of the metrics are blocked by your
consent settings
Dielectric and piezoelectric properties near the morphotropic phase boundary for 0.94BNT-0.06BT ceramics synthesized by the solid-state combustion technique
(2021-01-01)
Thatawong, Bhoowadol
;
Bhupaijit, Pamornnarumol
;
Lamyai, Yanwarood
;
Vittayakorn, Naratip
;
Bongkarn, Theerachai
Ceramics of 0.94Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>-0.06BaTiO<inf>3</inf> (0.94BNT-0.06BT) were synthesized by the solid-state combustion technique with various calcination and sintering temperatures (600-800 °C and 1100-1200 °C). A pure perovskite phase was obtained from the powder calcined at 750 °C for 2 h. The phase structure, microstructure, dielectric, ferroelectric and piezoelectric properties of the 0.94BNT-0.06BT ceramics were investigated. The XRD patterns showed coexisting phases of rhombohedral (R) and tetragonal (T) in all samples. Moreover, a good R:T phase ratio of 53:47, as found by Rietveld refinement, good grain growth and high density (5.84 g/cm3) were found with a sintering temperature of 1150 °C for 2 h. An excellent maximum dielectric constant (ε<inf>m</inf> = 8405), good ferroelectric properties (P<inf>r</inf> = 28.2 µC/cm2 and E<inf>c</inf> = 22.1 kV/cm) and a high piezoelectric coefficient (161 pC/N) were observed in this sample, which was near a morphotropic phase boundary (MPB).
Some of the metrics are blocked by your
consent settings
Structural, microstructure and electrical properties of La2O3-doped Bi0.5(Na0.68K0.22Li0.1)0.5TiO3 lead-free piezoelectric ceramics synthesized by the combustion technique
(2015-07-01)
Bhupaijit, Pamornnarumol
;
Kornphom, Chittakorn
;
Vittayakorn, Naratip
;
Bongkarn, Theerachai
The effect of firing temperatures on phase formation, microstructure and physical properties of [Bi<inf>0.5</inf>(Na<inf>0.68</inf>K<inf>0.22</inf>Li<inf>0.1</inf>)<inf>0.5</inf>TiO<inf>3</inf>] doped with La<inf>2</inf>O<inf>3</inf> at 0.1 wt% (BNKLLT) ceramics prepared by the combustion method was studied. Glycine was used as fuel and the ratio of raw material (corresponding oxidant metal nitrate) with fuel was about 1:0.56. The samples were calcined at 600-900 °C for 2 h and sintered at 1075-1150 °C for 2 h. The single rhombohedral peroveskite phase of BNKLLT powders was observed from the sample calcined at 750 °C for 2 h. The BNKLLT ceramics exhibited a pure peroveskite phase in all samples. The microstructures of the BNKLLT powders exhibited an agglomerated form while the grain ceramics exhibited a square shape. The average particle size and average grain size increased with increasing firing temperatures. The density, dielectric constant (ε<inf>r</inf> and ε<inf>m</inf>), P<inf>r</inf> and d<inf>33</inf> tended to increase with increasing sintering temperatures up to 1100 °C and then decreased. The maximum density (5.73 g/cm2), maximum dielectric constant (ε<inf>r</inf>~2572 and ε<inf>m</inf>~5536), good ferroelectric properties (P<inf>r</inf>~35.78 μC/cm2 and E<inf>c</inf>~22.42 kV/cm) and highest d<inf>33</inf> (210 pC/N) were obtained by the sample sintered at 1100 °C for 2 h.
Some of the metrics are blocked by your
consent settings
Fabrication of 0.62[0.75PMN-0.25PYbN]-0.38PT ceramics using one step calcination via combustion technique
(2013-01-01)
Kornphom, Chittakorn
;
Bhupaijit, Pamornnarumol
;
Vittayakorn, Naratip
;
Bongkarn, Theerachai
The fabrication of 0.62[0.75Pb(Mg<inf>1/3</inf>Nb<inf>2/3</inf>)O <inf>3</inf>-0.25Pb(Yb<inf>1/2</inf>Nb<inf>1/2</inf>)O<inf>3</inf>]-0. 38PbTiO<inf>3</inf> ceramics (abbreviated PMN-PYbN-PT) by combustion technique using one step calcination was studied. Glycine was used as fuel to reduce the reaction temperature. The phase formation, microstructure, density and dielectric properties were investigated. It was shown that calcination method is more effective than conventional solid state reaction. The crystal structure of PMN-PYbN-PT ceramics exhibited a single rhombohedral perovskite phase in samples sintered at temperature T < 1200°C. The pyrochlore phase was found in the samples sintered at 1200°C. The average grain size of the ceramics increases with increasing sintering temperature. The density and the maximum dielectric constant increases with increasing sintering temperatures up to 1150°C, and then decreases at higher temperatures. The maximum density (8.04 g/cm3), highest dielectric constant (19000) and excellent ferroelectric properties (P<inf>r</inf> ∼ 41.05 μC/cm2and E<inf>c</inf> ∼ 8.1 kV/cm) were obtained for the sample sintered at 1150°C. © 2013 Copyright Taylor and Francis Group, LLC.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results