KMITL

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

Browse

Search Results

Now showing 1 - 10 of 10

Some of the metrics are blocked by your
consent settings
Enhanced densification and thermoelectric properties of Ca3Co4O9 ceramics fabricated by solid-state combustion and hot-pressing
(2026-11-15)
Thatawong, Bhoowadol
;
Sriondee, Manlika
;
Chongsatan, Wistsarut
;
Palaporn, Dulyawich
;
Pinitsoontorn, Supree
The Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> powders were synthesized by the solid-state combustion method and then calcined at 775-875 °C for 6 h. The combination of combustion-derived fine powders and hot pressing was adopted to improve the densification and thermoelectric (TE) performance of Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> ceramics. Dense Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> ceramics were subsequently fabricated by hot-pressing to investigate the influence of hot-pressing temperature (800-950 °C, 2 h) on phase formation, microstructure, electrical, and TE properties. The Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> powder was obtained after calcination at 800 °C for 6 h and exhibited an average particle size of 0.55 μm. XRD analysis confirmed that Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> was the predominant phase in all hot-pressed samples. XPS analysis further confirmed the presence of oxygen vacancy (V<inf>O</inf>++)-related defects and mixed-valence cobalt species. FESEM observations revealed a dense microstructure composed of plate-like grains with an average grain size ranging from 0.61 to 0.96 μm. The bulk density ranged from 4.31 to 4.46 g/cm3, indicating dense ceramics. The electrical resistivity (ρ) decreased with increasing measured temperature for all samples. Among all samples, the ceramic hot-pressed at 900 °C exhibited the lowest ρ at 600 °C. The Seebeck coefficient (S) significantly increased from 150 μV/K to 223 μV/K, while the thermal conductivity (κ) decreased with increasing temperature. Due to the favorable combination of low ρ and high S, the sample hot-pressed at 900 °C achieved the highest power factor (PF) and a maximum dimensionless figure of merit (ZT) of 0.17 at 600 °C.
Some of the metrics are blocked by your
consent settings
Electric and magnetic properties of multiferroic CZFMO doped BNLTBKTBaT composite ceramics prepared via the solid-state combustion method
(2025-07-01)
Klinbanmor, Metarsit
;
Thatawong, Bhoowadol
;
Somsri, Widchaya
;
Prasertpalichat, Sasiphon
;
Vittayakorn, Naratip
The present research work describes in detail investigations of the multiferroic properties of (1-x) (0.85Bi<inf>0.5</inf>Na<inf>0.475</inf>Li<inf>0.025</inf>TiO<inf>3</inf>-0.11Bi<inf>0.5</inf>K<inf>0.5</inf>TiO<inf>3</inf>-0.04BaTiO<inf>3</inf>)-xCo<inf>0.6</inf>Zn<inf>0.4</inf>Fe<inf>1.7</inf>Mn<inf>0.3</inf>O<inf>4</inf> [(1-x)BNLTBKTBaT-xCZFMO]; x = 0, 0.05, 0.10, 0.15 and 0.20 composite ceramics, synthesized by the solid-state combustion technique. The effect of increasing x content on the phase structure, microstructure, electrical and magnetic properties of (1-x)BNLTBKTBaT-xCZFMO composite ceramics was investigated. X-ray diffraction patterns of the BNLTBKTBaT sample showed a pure perovskite phase (rhombohedral and tetragonal structures). When CZFMO was added, the XRD patterns showed a co-structure between perovskite and cubic spinel ferrite structures. The composite grains were composed of large and small sizes, which were composed of mainly the elements of BNLTBKTBaT and CZFMO, respectively. As x increased, the average grain size of the larger grains increased, and the smaller grains got smaller. The density decreased from 5.54 to 4.61 g/cm3 as x increased. Increasing the amount of CZFMO in BNLTBKTBaT also resulted in a decrease in the dielectric constant (ε<inf>r</inf>) and the remnant polarization (P<inf>r</inf>), with the leakage current observed at x = 0.20. The saturation magnetization (M<inf>s</inf>) and the magnetoelectric coupling coefficient (α<inf>E</inf>) increased with increased x. It was found that x = 0.15 gave the optimal electric, magnetic, and magnetoelectric properties (ε<inf>r</inf> = 425, P<inf>r</inf> = 1.64 μC/cm, M<inf>s</inf> = 1.1948 emu/g and α<inf>E</inf> = 4.88 mV/cm-Oe), which makes the composite potentially more applicable for information technology and spintronics devices.
Some of the metrics are blocked by your
consent settings
Improved Dielectric, Magnetic, and Multiferroic Properties of (Bi0.5Na0.5)0.7La0.3(Ti0.7Fe0.3)O3 Ceramics Synthesis by the Solid-State Combustion Technique
(2025-06-01)
Kornphom, Chittakorn
;
Somsri, Widchaya
;
Prasertpalichat, Sasipohn
;
Thatawong, Bhoowadol
;
Kruea-In, Chatchai
Lead-free (Bi<inf>0.5</inf>Na<inf>0.5</inf>)<inf>0.7</inf>La<inf>0.3</inf>(Ti<inf>0.7</inf>Fe<inf>0.3</inf>)O<inf>3</inf> ceramics (abbreviated as BNLTF) are synthesized by the solid-state combustion technique using glycine as fuel. The effect of the firing temperature (calcined between 700 and 800 °C for 2 h and sintered between at 800 and 900 °C for 2 h) on the phase structure, microstructure, electrical, and magnetic properties is investigated. Pure BNLTF powders are obtained with a calcination temperature of 750 °C for 2 h and the crystal size increases from 47 to 62 nm when the calcination temperature increases from 700 to 800 °C. All sintered BNLTF ceramics show a pure perovskite structure with a rhombohedral phase. The average grain size increases with increasing sintering temperatures. A well-packed microstructure with the highest density (5.98 g cm−3), good dielectric properties at room temperature (ε<inf>r</inf> ≈ 589 and tanδ ≈ 0.572), soft ferroelectric behavior, and excellent magnetic properties (M<inf>s</inf> ≈ 0.091 emu g−1, M<inf>r</inf> ≈ 0.0026 emu g−1) is obtained from the ceramic sintered at 875 °C for 2 h. The multiferroic BNLTF ceramic sintered at 875 °C has a maximum magnetoelectric coupling coefficient (α<inf>E</inf> ≈ 2.08 mV cm−1 Oe−1) when the magnetic field is near 4500 Oe.
Some of the metrics are blocked by your
consent settings
EFFECT OF FIRING TEMPERATURES ON THE PHASE STRUCTURE AND ELECTRICAL PROPERTIES OF BNT-BT-0.1NT CERAMICS SYNTHESIZED VIA THE SOLID-STATE COMBUSTION TECHNIQUE
(2025-01-01)
Thatawong, Bhoowadol
;
Tagerd, Kanyanut
;
Vittayakorn, Naratip
;
Udeye, Thanya
;
Bongkarn, Theerachai
Lead-free ceramic materials of 0.9(0.92Bi0.5Na0.5TiO3-0.08BaTiO3)-0.1NaTaO3 or BNT-BT-0.1NT were obtained using glycine as fuel by a solid-state combustion process. The significance of heat treatment conditions, including calcination at 600-800°C for 2 h and sintering at 1075-1175°C for 2 h, on the structure of the phase, microstructure, electrical and energy-storage properties of BNT-BT-0.1NT ceramics were performed. The perovskite phase was presented for all powder samples. BNT-BT-0.1NT powders calcined at the temperature of 750°C for 2 h showed a 100% pure perovskite phase. The particles morphology exhibited spherical shapes with a wide distribution. As the calcination temperature increased, the average particle size grew from 340 nm to 370 nm. Rietveld refinement confirmed that the BNT-BT-0.1NT ceramics possessed a uniform ABO3 structure with cohabiting of rhombohedral (R), tetragonal (T), and cubic (C) phases. With a rise in sintering temperature, the average grain size expanded from 0.85 μm to 2.66 μm, while the remnant polarization (P<inf>r</inf>) and coercive field (E<inf>c</inf>) decreased. The samples sintered at 1150oC for 2 h, the ceramic highlighted the highest dielectric constant (ε<inf>max</inf> ~ 1827), high density of 5.83 g/cm3. Under an applied electric field of 70 kV/cm, the maximum energy storage density reached 0.71 J/cm3.
Some of the metrics are blocked by your
consent settings
ELECTRIC AND MAGNETIC PROPERTIES OF Ba0.97Ca0.03Ti0.94Sn0.06O3-Mn0.85Ni0.15Zn0.15Fe2O4 MULTIFERROIC CERAMIC COMPOSITES FABRICATED VIA THE SOLID-STATE COMBUSTION TECHNIQUE
(2025-01-01)
Sonchaopria, Nutkamon
;
Meechob, Jirayut
;
Thatawong, Bhoowadol
;
Vittayakorn, Naratip
;
Pinitsoontorn, Supree
Multiferroic composites with the general formula (1-x)(Ba0.97Ca0.03Ti0.94Sn0.06O3)-x(Mn0.85Ni0.15Zn0.15Fe2O4) (BCTS/MNZF) (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared using the solid-state combustion method. The structure, morphology, dielectric, ferroelectric, magnetic, and magnetoelectric properties were analyzed. The samples were sintered at 1,300ºC for 2 h. The X-ray Diffraction (XRD) patterns revealed tetragonal perovskite, orthorhombic perovskite, and cubic spinel structures corresponding to the BCTS and MNZF phases. Secondary phases (Mn2O3 and SnO) appeared in the sintered samples with x>0.2. Increasing MNZF content enhanced ferrite grain growth in the composites. The dielectric constant showed an overall decreasing trend with increasing MNZF content, with a smaller effect at lower frequencies. At lower frequencies, the dielectric constant declined with increasing frequency before stabilizing around 10 kHz. As ferrite content increased, the density, dielectric constant, and magnetoelectric coefficient (αME) decreased from 5.66 to 5.12 g/cm³, 1388 to 862, and 7.24 to 4.05 mV/cm·Oe, respectively. While the saturation magnetization (Ms) rose substantially from 0.75 to 13.14 emu/g. These findings offer valuable insights into enhancing lead-free multiferroic composite ceramics for targeted applications in magnetoelectric devices.
Some of the metrics are blocked by your
consent settings
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
;
Didpim, Ratirom
;
Julphunthong, Phongthorn
;
Thatawong, Bhoowadol
;
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.
Some of the metrics are blocked by your
consent settings
Phase Formation, Morphology and Electrical Properties of Lead-Free BNBLT-xBSN Ceramics Synthesized via the Solid-State Combustion Technique
(2023-01-01)
Thatawong, Bhoowadol
;
Vittayakorn, Naratip
;
Rittidech, Aurawan
;
Bongkarn, Theerachai
Lead-free 1-x(Bi<inf>0.47</inf>Na<inf>0.47</inf>Ba<inf>0.06</inf>)<inf>0.95</inf>La<inf>0.05</inf>TiO<inf>3</inf>-xBa(Sn<inf>0.70</inf>Nb<inf>0.24</inf>)O<inf>3</inf> (BNBLT-xBSN) ceramics with x = 0, 0.01, 0.02, 0.03 and 0.04 mol.% were synthesized by the solid-state combustion technique with a calcination temperature of 750 °C for 2 h and a sintering temperature of 1150 °C for 2 h. The effect of BSN substitution on the phase formation, microstructure, dielectric, ferroelectric and energy storage properties of the BNBLT ceramics was investigated. With the substitution of BSN, the coexisting rhombohedral (R) and tetragonal (T) phases transformed into coexisting R and cubic (C) phase, verified by Rietveld refinement. The C phase increased with increased BSN content. The average grain size decreased from 1.14 to 0.89 µm when x increased to 0.03 and then increased to 0.96 µm. The measured density and maximum dielectric constant (ε <inf>m</inf>) tended to increase from 5.44 to 5.87 g/cm3 and 1800 to 1942 when x increased to 0.03, then decreased to 5.25 g/cm3 and 1501, respectively. The remanent polarization (P <inf>r</inf>) and coercive field (E <inf>c</inf>) decreased when x increased to 0.03. The 0.97BNBLT-0.03BSN ceramic exhibited the lowest energy loss density (W <inf>loss</inf> ∼ 0.10 J/cm3) and the highest energy-storage efficiency (η ∼ 77.3%) measured under an electric field of 70 kV/cm.
Some of the metrics are blocked by your
consent settings
Phase Structure, Microstructure, and Electrical Properties of Bi0.47Na0.47Ba0.06TiO3 Ceramics with (LiNb)4+ Substituted into B-Sites
(2023-01-01)
Luangpangai, Anupong
;
Thatawong, Bhoowadol
;
Charoenthai, Nipaphat
;
Vittayakorn, Naratip
;
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.
Some of the metrics are blocked by your
consent settings
Effects of the phase content and grain size on the electrical and energy storage properties of lead-free BNBT ceramics with substituted La3+
(2022-01-01)
Thatawong, Bhoowadol
;
Rittidech, Aurawan
;
Vittayakorn, Naratip
;
Bongkarn, Theerachai
Lead-free [(Bi<inf>0.5</inf>Na<inf>0.5</inf>)<inf>0.94</inf>Ba<inf>0.06</inf>]<inf>1-x</inf>La<inf>x</inf>TiO<inf>3</inf> (BNBT-xLa) ceramics with x = 0, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06 mol.% were synthesized by the solid-state combustion technique with calcination and sintering temperatures of 750 °C and 1150 °C, respectively, for 2 h. The phase formation, microstructure, dielectric, ferroelectric and energy storage properties of the BNBT-xLa ceramics were investigated. The XRD patterns of the powders showed a pure perovskite phase for all samples. The average particle size increased from 298 to 379 nm with increasing x. All ceramics showed coexisting rhombohedral and tetragonal phases. When x rose, the content of the tetragonal phase increased, as validated by the Rietveld refinement method. The average grain size decreased from 1.43 to 0.81 µm when x increased from 0 to 0.05 and then started to increase. The Curie temperature (T <inf>d</inf>) of the samples shifted to lower temperatures with rising x, owing to an increased tetragonal phase. The maximum dielectric constant (ε <inf>m</inf>), remanent polarization (P <inf>r</inf>) and coercive field (E <inf>c</inf>) decreased with increasing x. The BNBT-0.05La ceramic exhibited the smallest grain size, and lowest P <inf>r</inf> = 0.8 µC/cm2 and E <inf>c</inf> = 2.9 kV/cm, with the highest energy storage efficiency (η ∼ 78.31%) and a large effective energy storage density (W ∼ 0.83 J/cm3) measured in an electric field of 80 kV/cm.
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).

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results