Pharatree Jaita - Academia.edu (original) (raw)
Papers by Pharatree Jaita
Materials Research Bulletin, Nov 1, 2023
Microscopy Research and Technique, May 26, 2023
In this research, the bioceramics system of nano‐hydroxyapatite‐cobalt ferrite or Ca10(PO4)6(OH)2... more In this research, the bioceramics system of nano‐hydroxyapatite‐cobalt ferrite or Ca10(PO4)6(OH)2/xCoFe2O4 (HAP/xCF), where x = 0–3 vol%, were studied. The effect of CF concentration on phase evolution, physical, microstructure, mechanical, and magnetic properties as well as the in‐vitro apatite‐forming ability and cell culture analysis of the HAP ceramic was investigated. XRD revealed that all HAP/xCF ceramics showed high purity of hydroxyapatite with calcium and phosphate. However, the peak of the CF phase is noted for the HAP + 3 vol% CF ceramic. The densification and mechanical properties (HV, HK, σc, and σf) decreased with increasing the CF additive, which correlated to all HAP/xCF ceramics exhibited porous structure with increasing the percentage of porosity. The average grain size also increased with increasing the CF content. An improvement of magnetic behavior, which increasing of the Mr, Hc, and μB values, was obtained for the higher CF ceramics. In‐vitro apatite‐forming ability test suggested that the HAP + 3 vol% CF porous ceramic has a good apatite‐forming ability. The cell culture analysis indicated that the proliferation of cells was above 97% for the HAP + 3 vol% CF porous ceramic, which means that the prepared ceramic is biocompatible. Based on the obtained results indicated that these ceramics are promising biomedical application candidates.Research HighlightsWe fabricated the HAP/xCF ceramics by a simple solid‐state reaction method. The addition of CF into HAP exhibited magnetic improvement and produced the porous ceramic, which caused good apatite‐forming ability. The cell culture analysis indicated that the HAP + 3 vol% CF ceramic is biocompatible.
In this work, we simultaneously obtained a large d 33 and high T C in a lead-free piezoelectric s... more In this work, we simultaneously obtained a large d 33 and high T C in a lead-free piezoelectric system of (1x)K 0.5 Na 0.5 NbO 3 exBi 0.5 Na 0.5 Zr 0.85 Sn 0.15 O 3 [(1-x)KNNexBNZS]. This lead-free piezoelectric system was synthesized by conventional solid-state method. We investigated the microstructure and electrical properties of this system. The rhombohedral-tetragonal (R-T) phase coexistence is demonstrated in the ceramics with 0.05 x 0.06. Owing to the ReT phase coexistence as well as the enhancement of ferroelectric and dielectric properties, the ceramics with x ¼ 0.05 showed a large d 33 of~350 pC/N together with a high T C of~315 C, thereby illustrating that it is an effective way to obtain both large d 33 and high T C in KNN-based ceramics. It is believed that such a ceramic system with large d 33 and high T C is one of the promising candidates for piezoelectric devices.
Solid State Phenomena, Sep 1, 2018
In this work, the properties of lead-free 0.92(Bi0.5Na0.42K0.08)TiO3-0.08(BaNb0.01Ti0.99)O3 or 92... more In this work, the properties of lead-free 0.92(Bi0.5Na0.42K0.08)TiO3-0.08(BaNb0.01Ti0.99)O3 or 92BNKT-8BNbT ceramic has been investigated. The sample was fabricated by a solid-state reaction technique. The 92BNKT-8BNbT sample was well sintered and dense with high density value of 5.86 g/cm3. X-Ray diffraction (XRD) patterns showed a single perovskite phase with tetragonal symmetry and no impurity or secondary phases. The microstructure was analysed using a scanning electron microscopy (SEM). Average grain size was measured and calculated based on a mean linear intercept method. The ceramics had a cubic-like grain shape with an average grain size of 0.39 µm. The influence of temperature on the dielectric and ferroelectric properties of the ceramic was investigated. The dielectric curves exhibited broad transition peaks at Td and Tm, which were the characteristics of a diffuse phase transition. The polarization-electric field (P-E) hysteresis loop changed from well-saturated at room temperature (RT) to pinched-type loop at high temperature (HT) and the remanent polarization decreased from 21.25 µC/cm2 (at RT) to 5.96 µC/cm2 (at 150 °C).
Ferroelectrics, Apr 26, 2017
ABSTRACT Lead-free piezoelectric ceramics of Bi0.5(Na0.80K0.20)0.5TiO3 powders were prepared via ... more ABSTRACT Lead-free piezoelectric ceramics of Bi0.5(Na0.80K0.20)0.5TiO3 powders were prepared via a conventional solid-state reaction method, and effects of calcination temperature on many properties of the ceramics were investigated. XRD patterns for all ceramic samples showed coexistence between rhombohedral and tetragonal phases without any impurity. Calcination temperatures from 700 to 1000°C shifted depolarization temperature from 92 to 100°C. Dielectric and piezoelectric properties were improved and showed the optimum values for the ceramics which calcined at 800°C. The improvements of piezoelectric properties were related with the ceramic densification and MPB composition.
Journal of Alloys and Compounds, Mar 1, 2022
Ferroelectrics, Dec 10, 2022
Ferroelectrics, Dec 10, 2022
วารสารมหาวิทยาลัยนเรศวร: วิทยาศาสตร์และเทคโนโลยี (Naresuan University Journal: Science and Technology), May 4, 2016
The effect of sintering temperature on phase structure, densification and room temperature dielec... more The effect of sintering temperature on phase structure, densification and room temperature dielectric properties of B2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3(BNBT) lead-free ceramics prepared by a solid-state mixed oxide method was investigated and presented in this work. The X-ray diffraction analysis of the ceramics suggests that all samples exhibited a single perovskite structure without any secondary phase. The coexisting of both rhombohedral and tetragonal phases was identified over the entire sintering temperature range. The optimum sintering temperature for preparation of high-density BNBT + 2 wt% B2O3 ceramic was found to be 1050°C. Room temperature dielectric measurement data showed that the dielectric constant and dielectric loss values were increased with increasing the sintering temperature. Keywords: BNBT, Lead-free ceramics, Sintering, Phase, Dielectric Properties
Journal of Electroceramics, Sep 19, 2018
The (1-x)Ba(Zr 0.25 Ti 0.75)O 3-xSr(Fe 0.5 Nb 0.5)O 3 or (1-x)BZT-xSFN ceramics have been fabrica... more The (1-x)Ba(Zr 0.25 Ti 0.75)O 3-xSr(Fe 0.5 Nb 0.5)O 3 or (1-x)BZT-xSFN ceramics have been fabricated via a solid-state reaction technique. All ceramics exhibit a pure phase perovskite with cubic symmetry. The addition of a small amount of SFN (x = 0.1) produces an obvious change in dielectric behavior. Very high dielectric constants (ε r > 164,000 at 1 kHz and temperature > 150°C) are observed and the value is obviously higher than dielectric constants for Ba(Zr 0.25 Ti 0.75)O 3 and Sr(Fe 0.5 Nb 0.5)O 3 ceramics. The ferroelectric measurement data suggests that the unmodified sample exhibited a ferroelectric behavior. However, a transformation from a ferroelectric to a relaxor-like behavior is noted with increasing x concentration. Impedance Spectroscopy (IS) analysis indicates that the presence of excellent dielectric constants is due to the heterogeneous conduction in the ceramics after adding SFN, which can be explained in terms of the Maxwell-Wagner polarization mechanism.
Integrated Ferroelectrics, Feb 12, 2018
In this work, electric field-induced strain behavior and ferroelectric properties of xBCZT/PZT (w... more In this work, electric field-induced strain behavior and ferroelectric properties of xBCZT/PZT (with x = 0, 4 and 8 mol%) ceramics have been investigated. The E c and P r increased with increasing electric field and exhibited pinched-shape hysteresis loop at 60 kV/cm. The abnormal domain walls and switching behavior of the domains were used to discuss the above results. The strain value increased with increasing BCZT content and reached the maximum value of 0.27% (d * 33 = 450 pm/V) for the 4 mol% BCZT sample. This offered an opportunity to obtain a good candidate for using in piezoelectric applications.
Key Engineering Materials, Aug 1, 2018
This research investigated the effects of sintering temperatures on the structural, dielectric, f... more This research investigated the effects of sintering temperatures on the structural, dielectric, ferroelectric, piezoelectric and mechanical properties of lead-free Bismuth Sodium Potassium Titanate (BNKT) piezoelectric ceramics. The BNKT ceramics were prepared by solid-state mixed oxide method and sintering at temperature ranging from 1100 to 1150°C for 2 h. All ceramics sample showed highly density and reach a maximum at sintering temperature 1125°C of 5.81 g/cm3. X-ray diffraction patterns exhibited pure perovskite structure with coexisting of rhombohedral-tetragonal phases for all compositions. The microstructure was characterized by Scanning Electron Microscope (SEM), from SEM image the ceramics showed cubic-like grain shape. The average grain size increased with increasing sintering temperature. The dielectric permittivity showed the optimum sintering at 1125°C with reach a maximum dielectric constant of 4,194. Furthermore, at sintering temperature 1125°C present highest strain (Smax = 0.14%) with a large normalized strain coefficient (d*33 = Smax/Emax) of 233 pm/V.
Physica B-condensed Matter, Mar 1, 2019
SrFe 0.5 Nb 0.5 O 3 (SFN) ceramics doped with ZnO were synthesized via a conventional mixed oxide... more SrFe 0.5 Nb 0.5 O 3 (SFN) ceramics doped with ZnO were synthesized via a conventional mixed oxide technique. Phase formation investigation by X-ray diffraction technique (XRD) revealed that all ceramic samples exhibited pure perovskite phase. Grain size as observed by an electron microscopy (SEM), was found to decrease with increasing the additive concentration. Dielectric properties and other related properties of the ceramics were also investigated. Very high dielectric constants > 3.310 5 (at temperature 250 C and 1 kHz) were found for the 3 vol% doped samples. The impedance spectroscopy analysis suggested that the dielectric behavior of the samples could be linked with the Maxwell-Wagner polarization mechanism.
Integrated Ferroelectrics, Feb 12, 2018
This research was conducted to study influence of ferric oxide nanoparticles on the properties of... more This research was conducted to study influence of ferric oxide nanoparticles on the properties of modified BNKT ceramics. The optimum sintering temperature was 1125°C at which all compositions had low porosity (0.12-0.19%). Raman and XRD showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range. The P r , d 33 and g 33 were slightly degraded when the additive was added. The maximum room temperature dielectric (ε = 1689, tan δ = 0.0606) and mechanical properties (HV = 5.6 GPa, HK = 4.9 GPa, E = 93 GPa and K IC = 1.58 MPa.m 1/2) was obtained for the 2 vol% sample.
Surface & Coatings Technology, Nov 1, 2016
Abstract In the present work, strontium barium iron niobate (Sr 1- x Ba x Fe 0.5 Nb 0.5 O 3 ; SBF... more Abstract In the present work, strontium barium iron niobate (Sr 1- x Ba x Fe 0.5 Nb 0.5 O 3 ; SBFN) ( x = 0.0, 0.1 and 0.2) powders were synthesized via the molten salt technique . Pure phase perovskite powders were obtained at a relatively low calcination temperature of 800 °C which was 400 °C lower than for the solid-state reaction technique (conventional technique). SBFN ceramics were fabricated from the calcined powders and their properties were investigated. XRD data of the ceramics was consistent with an orthorhombic symmetry. All ceramics showed very high dielectric constants where the x = 0.1 ceramic showed an extremely high dielectric constant ( e r ~ 1.98 × 10 5 at 298 °C and 1 kHz, for an Ag electrode) when compared to SFN ceramics prepared by the conventional solid-state reaction technique. The dielectric behavior of the ceramics could be explained in terms of the Maxwell-Wagner mechanism as the ceramics exhibited heterogeneous conduction where an electrode response gave a strong effect in the low frequency and high temperature regions. In addition, the type of electrode (sample-electrode interface) also affected the dielectric constants of the ceramics.
Ferroelectrics, Nov 20, 2015
Lead-free piezoelectric ceramics with formula of (1-x)Bi0.5(Na0.80K0.20)0.5TiO3-xLiNbO3 or (1-x)B... more Lead-free piezoelectric ceramics with formula of (1-x)Bi0.5(Na0.80K0.20)0.5TiO3-xLiNbO3 or (1-x)BNKT-xLN (when x = 0, 0.005, 0.010, 0.015 and 0.020 mol fraction) were produced by a solid-state mixed oxide method. The ceramics with density ranging 5.38 - 5.68 g/cm3 were obtained by sintering at 1100°C. X-ray diffraction pattern showed that (1-x)BNKT-xLN ceramics exhibited pure perovskite structure. X-ray photoelectron spectroscopy analysis was used to identify of chemical composition, chemical state and binding energy of ionic species in the ceramics. Dielectric, ferroelectric and piezoelectric properties of all ceramics were investigated and found to be optimized at the composition of x = 0.005.
Current Applied Physics, May 1, 2011
Ferroelectric ceramics with formula Pb(Zr 0.52 Ti 0.48)O 3 /x(Bi 0.5 Na 0.5)TiO 3 (when x ¼ 0, 0.... more Ferroelectric ceramics with formula Pb(Zr 0.52 Ti 0.48)O 3 /x(Bi 0.5 Na 0.5)TiO 3 (when x ¼ 0, 0.1, 0.5, 1.0 and 3.0 wt%) were prepared by a solid-state mixed-oxide method and sintered at the temperature between 1050 and 1200 C for 2 h to obtain dense ceramics. It was found that the optimum sintering temperature was 1200 C at which all the samples had relative density at least 96% of their theoretical values. Phase analysis using X-ray diffraction showed tetragonal and rhombohedral perovskite structure of PZT with no BNT peak detected, indicating that completed solid solutions occurred for all compositions. Scanning electron micrographs of fractured PZT/BNT ceramics showed equiaxed grain shape with mixed-mode of transgranular and intergranular fractures. Addition of BNT significantly decreased grain size of the PZT ceramic. Measurement of room temperature dielectric constant indicated a gradual increase with increasing BNT content. Results of ferroelectric characterization showed a slight decrease of remanent polarization and coercive field for BNT-added samples, suggesting ceramics which could be easily poled. Good piezoelectric coefficient (d 33) could be maintained and comparable to that of pure PZT ceramic for the sample with 1.0 wt% BNT addition.
Solid State Sciences, Sep 1, 2010
In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on struc... more In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on structure and properties of lead zirconate titanate (PZT) ceramics were investigated. PZT ceramics with addition of 0.1 e3.0 wt%BNLT were fabricated by a solid-state mixed oxide method and sintering at 1050e1200 C for 2 h to obtain dense ceramics with at least 96% of theoretical density. X-ray diffraction indicated that complete solid solution occurred for all compositions. Phase identification showed both tetragonal and rhombohedral perovskite structure of PZT with no BNLT phase detected. Scanning electron micrographs of fractured PZT/BNLT ceramics showed equiaxed grain shape with both transgranular and intergranular fracture modes. Addition of BNLT was also found to reduce densification and effectively limited grain growth of PZT ceramic. Optimum Hv and K IC values were found to be 4.85 GPa and 1.56 MPa.m 1/2 for PZT/ 0.5 wt%BNLT sample. Among PZT/BNLT samples, room temperature dielectric constant seemed to be improved with increasing BNLT content. The maximum piezoelectric coefficient values were observed in pure PZT ceramic and were slightly decreased in BNLT-added samples. Small reduction of remanent polarization and coercive field in hysteresis loops was observed in BNLT-added samples, indicating a slightly suppressed ferroelectric interaction in this material system.
Materials Research Bulletin, Aug 1, 2020
Abstract The effects of ZnO nanoparticle doping on the phase formation, phase transition, dielect... more Abstract The effects of ZnO nanoparticle doping on the phase formation, phase transition, dielectric, ferroelectric, piezoelectric, and energy harvesting properties of Bi0.5(Na0.84K0.16)0.5TiO3/xZnO or BNKT16/xZnO (with x = 0, 0.02, 0.04, and 0.06 mol fraction) were investigated. The samples were synthesized through a solid-state reaction method. X-ray diffraction results showed that all samples exhibited a single perovskite phase, except the x = 0.06 sample. The depolarization temperature (Td) value, determined by the thermally stimulated depolarization current (TSDC), tended to vanish with increasing ZnO content. The additive also promoted a diffuse transition at Td. High polarization was observed for the x = 0.04 sample: remanent polarization (Pr) = 53.33 μC/cm2 and saturation polarization (Ps) = 55.34 μC/cm2 with large improvements for Pr and Ps values (98 % and 92 %, respectively, as compared to the base composition) and a decrease in the coercive field (Ec). Improvements of piezoelectric coefficients (d33 and g33) were also found for the x = 0.04 sample. This therefore produced an improvement of energy harvesting performance across the samples.
Ceramics International, Nov 1, 2016
A relation between phase transition region and the tolerance factor (t) in BKT-BMgT ceramics was ... more A relation between phase transition region and the tolerance factor (t) in BKT-BMgT ceramics was established according to the reported literature for various BKT-based ceramics. In order to confirm the prediction, lead-free piezoelectric ceramics based on (1−x)(Bi0.5K0.50)TiO3-xBi(Mg0.50Ti0.50)O3 or (1−x)BKT-xBMgT (x=0.0–0.2) were synthesized by a solid-state reaction method. The compositional dependence of the crystal structure, electrical properties and strain behavior of all ceramics was examined. The crystal structure analysis indicated that the phase transition region was located over the compositional region 0.05<x<0.10 (t∼1.0170–1.0130), over which the crystal structure was seen to change from a tetragonal to a pseudo-cubic phase. The tolerance factor of these compositions were closely matched to expected values for the phase transition region in BKT-based ceramics (t∼1.0123–1.0192), as reported in the literatures. The ceramics in these transition region (0.05<x<0.10) showed a noticeable enhancement in dielectric constant (er=1150–1510, Tm=323–347°C), ferroelectric properties (Pr=9.7–11.7 μC/cm2) and piezoelectric properties (d33=205–225 pC/N) properties, as compared to pure BKT ceramic. Furthermore, the BKT-0.10BMgT sample displayed a high Smax=0.22% and d*33=314 pm/V which was ∼20–30% higher than that of unmodified-BKT ceramic. The obtained results suggested that a study of the tolerance factor may be employed in a search for the phase transition region with excellent piezoelectric properties in various ceramic systems.
Materials Research Bulletin, Nov 1, 2023
Microscopy Research and Technique, May 26, 2023
In this research, the bioceramics system of nano‐hydroxyapatite‐cobalt ferrite or Ca10(PO4)6(OH)2... more In this research, the bioceramics system of nano‐hydroxyapatite‐cobalt ferrite or Ca10(PO4)6(OH)2/xCoFe2O4 (HAP/xCF), where x = 0–3 vol%, were studied. The effect of CF concentration on phase evolution, physical, microstructure, mechanical, and magnetic properties as well as the in‐vitro apatite‐forming ability and cell culture analysis of the HAP ceramic was investigated. XRD revealed that all HAP/xCF ceramics showed high purity of hydroxyapatite with calcium and phosphate. However, the peak of the CF phase is noted for the HAP + 3 vol% CF ceramic. The densification and mechanical properties (HV, HK, σc, and σf) decreased with increasing the CF additive, which correlated to all HAP/xCF ceramics exhibited porous structure with increasing the percentage of porosity. The average grain size also increased with increasing the CF content. An improvement of magnetic behavior, which increasing of the Mr, Hc, and μB values, was obtained for the higher CF ceramics. In‐vitro apatite‐forming ability test suggested that the HAP + 3 vol% CF porous ceramic has a good apatite‐forming ability. The cell culture analysis indicated that the proliferation of cells was above 97% for the HAP + 3 vol% CF porous ceramic, which means that the prepared ceramic is biocompatible. Based on the obtained results indicated that these ceramics are promising biomedical application candidates.Research HighlightsWe fabricated the HAP/xCF ceramics by a simple solid‐state reaction method. The addition of CF into HAP exhibited magnetic improvement and produced the porous ceramic, which caused good apatite‐forming ability. The cell culture analysis indicated that the HAP + 3 vol% CF ceramic is biocompatible.
In this work, we simultaneously obtained a large d 33 and high T C in a lead-free piezoelectric s... more In this work, we simultaneously obtained a large d 33 and high T C in a lead-free piezoelectric system of (1x)K 0.5 Na 0.5 NbO 3 exBi 0.5 Na 0.5 Zr 0.85 Sn 0.15 O 3 [(1-x)KNNexBNZS]. This lead-free piezoelectric system was synthesized by conventional solid-state method. We investigated the microstructure and electrical properties of this system. The rhombohedral-tetragonal (R-T) phase coexistence is demonstrated in the ceramics with 0.05 x 0.06. Owing to the ReT phase coexistence as well as the enhancement of ferroelectric and dielectric properties, the ceramics with x ¼ 0.05 showed a large d 33 of~350 pC/N together with a high T C of~315 C, thereby illustrating that it is an effective way to obtain both large d 33 and high T C in KNN-based ceramics. It is believed that such a ceramic system with large d 33 and high T C is one of the promising candidates for piezoelectric devices.
Solid State Phenomena, Sep 1, 2018
In this work, the properties of lead-free 0.92(Bi0.5Na0.42K0.08)TiO3-0.08(BaNb0.01Ti0.99)O3 or 92... more In this work, the properties of lead-free 0.92(Bi0.5Na0.42K0.08)TiO3-0.08(BaNb0.01Ti0.99)O3 or 92BNKT-8BNbT ceramic has been investigated. The sample was fabricated by a solid-state reaction technique. The 92BNKT-8BNbT sample was well sintered and dense with high density value of 5.86 g/cm3. X-Ray diffraction (XRD) patterns showed a single perovskite phase with tetragonal symmetry and no impurity or secondary phases. The microstructure was analysed using a scanning electron microscopy (SEM). Average grain size was measured and calculated based on a mean linear intercept method. The ceramics had a cubic-like grain shape with an average grain size of 0.39 µm. The influence of temperature on the dielectric and ferroelectric properties of the ceramic was investigated. The dielectric curves exhibited broad transition peaks at Td and Tm, which were the characteristics of a diffuse phase transition. The polarization-electric field (P-E) hysteresis loop changed from well-saturated at room temperature (RT) to pinched-type loop at high temperature (HT) and the remanent polarization decreased from 21.25 µC/cm2 (at RT) to 5.96 µC/cm2 (at 150 °C).
Ferroelectrics, Apr 26, 2017
ABSTRACT Lead-free piezoelectric ceramics of Bi0.5(Na0.80K0.20)0.5TiO3 powders were prepared via ... more ABSTRACT Lead-free piezoelectric ceramics of Bi0.5(Na0.80K0.20)0.5TiO3 powders were prepared via a conventional solid-state reaction method, and effects of calcination temperature on many properties of the ceramics were investigated. XRD patterns for all ceramic samples showed coexistence between rhombohedral and tetragonal phases without any impurity. Calcination temperatures from 700 to 1000°C shifted depolarization temperature from 92 to 100°C. Dielectric and piezoelectric properties were improved and showed the optimum values for the ceramics which calcined at 800°C. The improvements of piezoelectric properties were related with the ceramic densification and MPB composition.
Journal of Alloys and Compounds, Mar 1, 2022
Ferroelectrics, Dec 10, 2022
Ferroelectrics, Dec 10, 2022
วารสารมหาวิทยาลัยนเรศวร: วิทยาศาสตร์และเทคโนโลยี (Naresuan University Journal: Science and Technology), May 4, 2016
The effect of sintering temperature on phase structure, densification and room temperature dielec... more The effect of sintering temperature on phase structure, densification and room temperature dielectric properties of B2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3(BNBT) lead-free ceramics prepared by a solid-state mixed oxide method was investigated and presented in this work. The X-ray diffraction analysis of the ceramics suggests that all samples exhibited a single perovskite structure without any secondary phase. The coexisting of both rhombohedral and tetragonal phases was identified over the entire sintering temperature range. The optimum sintering temperature for preparation of high-density BNBT + 2 wt% B2O3 ceramic was found to be 1050°C. Room temperature dielectric measurement data showed that the dielectric constant and dielectric loss values were increased with increasing the sintering temperature. Keywords: BNBT, Lead-free ceramics, Sintering, Phase, Dielectric Properties
Journal of Electroceramics, Sep 19, 2018
The (1-x)Ba(Zr 0.25 Ti 0.75)O 3-xSr(Fe 0.5 Nb 0.5)O 3 or (1-x)BZT-xSFN ceramics have been fabrica... more The (1-x)Ba(Zr 0.25 Ti 0.75)O 3-xSr(Fe 0.5 Nb 0.5)O 3 or (1-x)BZT-xSFN ceramics have been fabricated via a solid-state reaction technique. All ceramics exhibit a pure phase perovskite with cubic symmetry. The addition of a small amount of SFN (x = 0.1) produces an obvious change in dielectric behavior. Very high dielectric constants (ε r > 164,000 at 1 kHz and temperature > 150°C) are observed and the value is obviously higher than dielectric constants for Ba(Zr 0.25 Ti 0.75)O 3 and Sr(Fe 0.5 Nb 0.5)O 3 ceramics. The ferroelectric measurement data suggests that the unmodified sample exhibited a ferroelectric behavior. However, a transformation from a ferroelectric to a relaxor-like behavior is noted with increasing x concentration. Impedance Spectroscopy (IS) analysis indicates that the presence of excellent dielectric constants is due to the heterogeneous conduction in the ceramics after adding SFN, which can be explained in terms of the Maxwell-Wagner polarization mechanism.
Integrated Ferroelectrics, Feb 12, 2018
In this work, electric field-induced strain behavior and ferroelectric properties of xBCZT/PZT (w... more In this work, electric field-induced strain behavior and ferroelectric properties of xBCZT/PZT (with x = 0, 4 and 8 mol%) ceramics have been investigated. The E c and P r increased with increasing electric field and exhibited pinched-shape hysteresis loop at 60 kV/cm. The abnormal domain walls and switching behavior of the domains were used to discuss the above results. The strain value increased with increasing BCZT content and reached the maximum value of 0.27% (d * 33 = 450 pm/V) for the 4 mol% BCZT sample. This offered an opportunity to obtain a good candidate for using in piezoelectric applications.
Key Engineering Materials, Aug 1, 2018
This research investigated the effects of sintering temperatures on the structural, dielectric, f... more This research investigated the effects of sintering temperatures on the structural, dielectric, ferroelectric, piezoelectric and mechanical properties of lead-free Bismuth Sodium Potassium Titanate (BNKT) piezoelectric ceramics. The BNKT ceramics were prepared by solid-state mixed oxide method and sintering at temperature ranging from 1100 to 1150°C for 2 h. All ceramics sample showed highly density and reach a maximum at sintering temperature 1125°C of 5.81 g/cm3. X-ray diffraction patterns exhibited pure perovskite structure with coexisting of rhombohedral-tetragonal phases for all compositions. The microstructure was characterized by Scanning Electron Microscope (SEM), from SEM image the ceramics showed cubic-like grain shape. The average grain size increased with increasing sintering temperature. The dielectric permittivity showed the optimum sintering at 1125°C with reach a maximum dielectric constant of 4,194. Furthermore, at sintering temperature 1125°C present highest strain (Smax = 0.14%) with a large normalized strain coefficient (d*33 = Smax/Emax) of 233 pm/V.
Physica B-condensed Matter, Mar 1, 2019
SrFe 0.5 Nb 0.5 O 3 (SFN) ceramics doped with ZnO were synthesized via a conventional mixed oxide... more SrFe 0.5 Nb 0.5 O 3 (SFN) ceramics doped with ZnO were synthesized via a conventional mixed oxide technique. Phase formation investigation by X-ray diffraction technique (XRD) revealed that all ceramic samples exhibited pure perovskite phase. Grain size as observed by an electron microscopy (SEM), was found to decrease with increasing the additive concentration. Dielectric properties and other related properties of the ceramics were also investigated. Very high dielectric constants > 3.310 5 (at temperature 250 C and 1 kHz) were found for the 3 vol% doped samples. The impedance spectroscopy analysis suggested that the dielectric behavior of the samples could be linked with the Maxwell-Wagner polarization mechanism.
Integrated Ferroelectrics, Feb 12, 2018
This research was conducted to study influence of ferric oxide nanoparticles on the properties of... more This research was conducted to study influence of ferric oxide nanoparticles on the properties of modified BNKT ceramics. The optimum sintering temperature was 1125°C at which all compositions had low porosity (0.12-0.19%). Raman and XRD showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range. The P r , d 33 and g 33 were slightly degraded when the additive was added. The maximum room temperature dielectric (ε = 1689, tan δ = 0.0606) and mechanical properties (HV = 5.6 GPa, HK = 4.9 GPa, E = 93 GPa and K IC = 1.58 MPa.m 1/2) was obtained for the 2 vol% sample.
Surface & Coatings Technology, Nov 1, 2016
Abstract In the present work, strontium barium iron niobate (Sr 1- x Ba x Fe 0.5 Nb 0.5 O 3 ; SBF... more Abstract In the present work, strontium barium iron niobate (Sr 1- x Ba x Fe 0.5 Nb 0.5 O 3 ; SBFN) ( x = 0.0, 0.1 and 0.2) powders were synthesized via the molten salt technique . Pure phase perovskite powders were obtained at a relatively low calcination temperature of 800 °C which was 400 °C lower than for the solid-state reaction technique (conventional technique). SBFN ceramics were fabricated from the calcined powders and their properties were investigated. XRD data of the ceramics was consistent with an orthorhombic symmetry. All ceramics showed very high dielectric constants where the x = 0.1 ceramic showed an extremely high dielectric constant ( e r ~ 1.98 × 10 5 at 298 °C and 1 kHz, for an Ag electrode) when compared to SFN ceramics prepared by the conventional solid-state reaction technique. The dielectric behavior of the ceramics could be explained in terms of the Maxwell-Wagner mechanism as the ceramics exhibited heterogeneous conduction where an electrode response gave a strong effect in the low frequency and high temperature regions. In addition, the type of electrode (sample-electrode interface) also affected the dielectric constants of the ceramics.
Ferroelectrics, Nov 20, 2015
Lead-free piezoelectric ceramics with formula of (1-x)Bi0.5(Na0.80K0.20)0.5TiO3-xLiNbO3 or (1-x)B... more Lead-free piezoelectric ceramics with formula of (1-x)Bi0.5(Na0.80K0.20)0.5TiO3-xLiNbO3 or (1-x)BNKT-xLN (when x = 0, 0.005, 0.010, 0.015 and 0.020 mol fraction) were produced by a solid-state mixed oxide method. The ceramics with density ranging 5.38 - 5.68 g/cm3 were obtained by sintering at 1100°C. X-ray diffraction pattern showed that (1-x)BNKT-xLN ceramics exhibited pure perovskite structure. X-ray photoelectron spectroscopy analysis was used to identify of chemical composition, chemical state and binding energy of ionic species in the ceramics. Dielectric, ferroelectric and piezoelectric properties of all ceramics were investigated and found to be optimized at the composition of x = 0.005.
Current Applied Physics, May 1, 2011
Ferroelectric ceramics with formula Pb(Zr 0.52 Ti 0.48)O 3 /x(Bi 0.5 Na 0.5)TiO 3 (when x ¼ 0, 0.... more Ferroelectric ceramics with formula Pb(Zr 0.52 Ti 0.48)O 3 /x(Bi 0.5 Na 0.5)TiO 3 (when x ¼ 0, 0.1, 0.5, 1.0 and 3.0 wt%) were prepared by a solid-state mixed-oxide method and sintered at the temperature between 1050 and 1200 C for 2 h to obtain dense ceramics. It was found that the optimum sintering temperature was 1200 C at which all the samples had relative density at least 96% of their theoretical values. Phase analysis using X-ray diffraction showed tetragonal and rhombohedral perovskite structure of PZT with no BNT peak detected, indicating that completed solid solutions occurred for all compositions. Scanning electron micrographs of fractured PZT/BNT ceramics showed equiaxed grain shape with mixed-mode of transgranular and intergranular fractures. Addition of BNT significantly decreased grain size of the PZT ceramic. Measurement of room temperature dielectric constant indicated a gradual increase with increasing BNT content. Results of ferroelectric characterization showed a slight decrease of remanent polarization and coercive field for BNT-added samples, suggesting ceramics which could be easily poled. Good piezoelectric coefficient (d 33) could be maintained and comparable to that of pure PZT ceramic for the sample with 1.0 wt% BNT addition.
Solid State Sciences, Sep 1, 2010
In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on struc... more In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on structure and properties of lead zirconate titanate (PZT) ceramics were investigated. PZT ceramics with addition of 0.1 e3.0 wt%BNLT were fabricated by a solid-state mixed oxide method and sintering at 1050e1200 C for 2 h to obtain dense ceramics with at least 96% of theoretical density. X-ray diffraction indicated that complete solid solution occurred for all compositions. Phase identification showed both tetragonal and rhombohedral perovskite structure of PZT with no BNLT phase detected. Scanning electron micrographs of fractured PZT/BNLT ceramics showed equiaxed grain shape with both transgranular and intergranular fracture modes. Addition of BNLT was also found to reduce densification and effectively limited grain growth of PZT ceramic. Optimum Hv and K IC values were found to be 4.85 GPa and 1.56 MPa.m 1/2 for PZT/ 0.5 wt%BNLT sample. Among PZT/BNLT samples, room temperature dielectric constant seemed to be improved with increasing BNLT content. The maximum piezoelectric coefficient values were observed in pure PZT ceramic and were slightly decreased in BNLT-added samples. Small reduction of remanent polarization and coercive field in hysteresis loops was observed in BNLT-added samples, indicating a slightly suppressed ferroelectric interaction in this material system.
Materials Research Bulletin, Aug 1, 2020
Abstract The effects of ZnO nanoparticle doping on the phase formation, phase transition, dielect... more Abstract The effects of ZnO nanoparticle doping on the phase formation, phase transition, dielectric, ferroelectric, piezoelectric, and energy harvesting properties of Bi0.5(Na0.84K0.16)0.5TiO3/xZnO or BNKT16/xZnO (with x = 0, 0.02, 0.04, and 0.06 mol fraction) were investigated. The samples were synthesized through a solid-state reaction method. X-ray diffraction results showed that all samples exhibited a single perovskite phase, except the x = 0.06 sample. The depolarization temperature (Td) value, determined by the thermally stimulated depolarization current (TSDC), tended to vanish with increasing ZnO content. The additive also promoted a diffuse transition at Td. High polarization was observed for the x = 0.04 sample: remanent polarization (Pr) = 53.33 μC/cm2 and saturation polarization (Ps) = 55.34 μC/cm2 with large improvements for Pr and Ps values (98 % and 92 %, respectively, as compared to the base composition) and a decrease in the coercive field (Ec). Improvements of piezoelectric coefficients (d33 and g33) were also found for the x = 0.04 sample. This therefore produced an improvement of energy harvesting performance across the samples.
Ceramics International, Nov 1, 2016
A relation between phase transition region and the tolerance factor (t) in BKT-BMgT ceramics was ... more A relation between phase transition region and the tolerance factor (t) in BKT-BMgT ceramics was established according to the reported literature for various BKT-based ceramics. In order to confirm the prediction, lead-free piezoelectric ceramics based on (1−x)(Bi0.5K0.50)TiO3-xBi(Mg0.50Ti0.50)O3 or (1−x)BKT-xBMgT (x=0.0–0.2) were synthesized by a solid-state reaction method. The compositional dependence of the crystal structure, electrical properties and strain behavior of all ceramics was examined. The crystal structure analysis indicated that the phase transition region was located over the compositional region 0.05<x<0.10 (t∼1.0170–1.0130), over which the crystal structure was seen to change from a tetragonal to a pseudo-cubic phase. The tolerance factor of these compositions were closely matched to expected values for the phase transition region in BKT-based ceramics (t∼1.0123–1.0192), as reported in the literatures. The ceramics in these transition region (0.05<x<0.10) showed a noticeable enhancement in dielectric constant (er=1150–1510, Tm=323–347°C), ferroelectric properties (Pr=9.7–11.7 μC/cm2) and piezoelectric properties (d33=205–225 pC/N) properties, as compared to pure BKT ceramic. Furthermore, the BKT-0.10BMgT sample displayed a high Smax=0.22% and d*33=314 pm/V which was ∼20–30% higher than that of unmodified-BKT ceramic. The obtained results suggested that a study of the tolerance factor may be employed in a search for the phase transition region with excellent piezoelectric properties in various ceramic systems.