389 results
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2. Dielectric and AC conductivity properties dependant simultaneously on T and ω of microwave sintered Ba0.997Pr0.003TiO3 ceramic: an experimental and simulation studies using modified Lorentz equations derived from Lorentz equation
- Author
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Mahboob, Syed, Rizwana, and Kumar, G. S.
- Subjects
DIELECTRICS ,ACTIVATION energy ,ARRHENIUS equation ,CERAMICS ,MICROWAVES - Abstract
In our earlier studies we have shown procedure for the estimation of activation energy and relaxation times directly from the dielectric and AC conductivity data simultaneously dependant on T and ω using modified Lorentz equation instead of well-known Arrhenius, modified Arrhenius and Vogel-Fulcher laws. In the present paper we have carried out similar experimental and simulation studies on the dielectric and AC conductivity data using modified Lorentz equations on the ceramic compound (Ba
0.997 Pr0.003 TiO3 ). The obtained results on the activation energy and relaxation times are presented in this paper. [ABSTRACT FROM AUTHOR]- Published
- 2023
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3. The effect of ZnO and MnO2 as sintering aids in the preparation of potassium sodium niobate ceramics and electrical characterizations.
- Author
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Aniz, Irom Monika and Maisnam, Mamata
- Subjects
POTASSIUM niobate ,PIEZOELECTRIC ceramics ,CERAMICS ,ELECTRON microscope techniques ,ELECTRIC properties ,METALLIC oxides ,YTTRIUM oxides ,MANGANITE ,PIEZOELECTRIC materials - Abstract
Potassium sodium niobate (KNN) is an environmentally compatible piezoelectric material for substituting harmful lead-based ceramics. KNN-based ceramics have excellent piezoelectric properties with high Curie temperature. But, KNN faces difficulties during the processing like volatilization of alkali elements, chemical inhomogeneity, low densification, etc. The objective of this research is to investigate the impact of certain metal oxides additions like ZnO and MnO
2 as sintering aids to solve the problems of the preparation and hence study the structural and electric properties of K0.5 N0.5 NbO3 (KNN) ceramics. ZnO and MnO2 added potassium sodium niobate, K0.5 N0.5 NbO3 was prepared by using the ceramic method. The prepared samples were sintered at 1000 °C for 2h conventionally. The structural properties of the ceramics have been analyzed by using X-Ray Diffractometer. The study demonstrates the formation of the orthorhombic-symmetric perovskite phase in all the prepared samples. The microstructural behavior of the ceramics has been characterized by techniques such as scanning electron microscopy (SEM) and compositional properties were studied by energy dispersive x-ray (EDAX). The effects of metal oxide additions on the electronic properties such as dielectric constant, dielectric loss, impedance properties, Nyquist plot, etc., were studied. The results have been analyzed and discussed in the paper. [ABSTRACT FROM AUTHOR]- Published
- 2024
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4. Structural, Electrical Studies of K0.47Na0.47Li0.06NbO3+(x) Bi0.5Na0.5ZrO3 Composites.
- Author
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Chaliha, Chiranjit and Maisnam, Mamata
- Subjects
MORPHOTROPIC phase boundaries ,PARTICLE size distribution ,X-ray diffraction ,COMPOSITE materials ,CERAMICS ,PHASE transitions - Abstract
Through a typical solid-state reaction followed by planetary ball milling, ABO
3 structured perovskite Bi0.5 Na0.5 ZrO3 (BNZ) was employed as an additive to create the lead-free piezoceramic composite having compositional formula K0.47 Na0.47 Li0.06 NbO3 +(x)Bi0.5 Na0.5 ZrO3 where x = 0.0 wt% to 0.5 wt%. The prepared composites were characterized with the help of XRD, SEM, and FTIR. The XRD results indicated manifestation of morphotropic phase boundary (MPB), i.e. orthorhombic-tetragonal (O-T) phase boundary, for 0.4 wt% and 0.5 wt%. The SEM pictures revealed the microstructural properties of grain-grain size distribution and the average grain size of the composites. The elemental composition examination using EDAX revealed no foreign element contamination. The FTIR examination verified the development of perovskite, indicating that the BNZ has correctly fused into the KNLN matrix. The DC resistivity (ρdc) behavior was determined from IV and IR curves measured at room temperature together with varied temperature line up from 30 °C to 150 °C and a high dc resistivity ρdc of order ≈ 109 Ω cm was obtained for all the ceramics. The results have been analyzed and the mechanism pertaining to the results has been discussed in the paper. Thus the main idea was to develop a lead-free piezoceramic composite by incorporating Bi0.5 Na0.5 ZrO3 as an additive and investigating its effect on the above mentioned properties of the composite material. [ABSTRACT FROM AUTHOR]- Published
- 2024
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5. Structural, micro-structural, resistive and capacitive characteristics of Mn modified lead zirconate titanate: Pb(Zr0.35–xMnxTi0.65)O3 (x = 0–0.10) ceramics.
- Author
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Tiwari, Balgovind, Babu, T., and Choudhary, R. N. P.
- Subjects
LEAD zirconate titanate ,FIELD emission electron microscopes ,TITANATES ,CERAMICS ,ELECTRIC impedance ,LEAD titanate ,RELAXATION phenomena ,X-ray diffraction - Abstract
In this paper, detailed studies of effect of small amount of manganese substitution (at the zirconium site) on the structural, micro-structural, and electrical characteristics of lead zirconate titanate of Pb(Zr
0 .35–x Mnx Ti0 . 65 )O3; x = 0, 0.02, 0.06, 0.10 (PZMT)) have been reported. The materials were prepared by using standard ceramic technology. The formation of the compounds and their basic crystal data have been studied through X-ray diffraction (XRD) method. The crystallite size and lattice strain of the compounds, evaluated from Scherrer's and Hall Williamson (H-W) equations, is found to be in the range of 40–50 nm and 11 × 10−4 to 50 × 10−4 , respectively. Microstructures of different magnifications, revealing the surface nature of the compounds, have been recorded by field emission scanning electron microscope (FESEM). Effect of Mn+4 ions on electrical behavior (electrical impedance (Z*), electrical modulus (M*), conduction and relaxation phenomenon) of PZMT systems, over wide range of temperature and frequency, has been studied. [ABSTRACT FROM AUTHOR]- Published
- 2024
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6. Evidence of an unusual magnetic behavior at the morphotropic phase boundary of La doped BiFeO3 ceramics.
- Author
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Oliveira, Roger Carvalho, Volnistem, Eduardo Azzolini, dos Santos, Ivair Aparecido, Dias, Gustavo Sanguino, Cotica, Luiz Fernando, Eiras, José Antonio, and Garcia, Ducinei
- Subjects
HYSTERESIS loop ,LEAD-free ceramics ,MORPHOTROPIC phase boundaries ,BISMUTH iron oxide ,CERAMICS ,MAGNETIZATION - Abstract
In this paper, Bi
(1-x) Lax FeO3 ceramics were processed considering two compositions inside (Bi0.85 La0.15 FeO3 ) and outside (Bi0.95 La0.05 FeO3 ) the morphotropic phase boundary that separates the rhombohedral and orthorhombic phases. An unusual magnetic behavior, characterized by a double hysteresis loop, was observed at room temperature for the Bi0.85 La0.15 FeO3 sample. Langevin analyses revealed that this behavior is related to both the linear and non-linear components of the magnetization, indicating possible changes of the magnetic phase with doping. [ABSTRACT FROM AUTHOR]- Published
- 2023
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7. Influence of doping mode on phase structure and electrical properties of antiferroelectric ceramics.
- Author
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Wang, Yongfeng, Cao, Jing, Li, Zhao, and Wu, Kunyao
- Subjects
DOPING agents (Chemistry) ,FERROELECTRIC ceramics ,CERAMIC materials ,CERAMICS ,LEAD zirconate titanate ,ENERGY storage ,DIELECTRIC properties - Abstract
The ferroelectric, lead-free perovskite sodium bismuth titanate-barium titanate (BNT-BT) has excellent electrical performance and is now recognized as a possible alternative material for lead zirconate titanate (PZT). It can be doped with some active elements to form a solid solution with a morphotropic phase boundary (MPB), where the solid solution has high dielectric properties and high energy storage performance. In this paper, the research results of BNT-BLT, BNT-BLZT, BNT-BSLZT, BNT-BMNLT and BNT-BST-KNN ceramic materials are summarized, and the influence of their doping mode on the phase structure and electrical properties are analyzed. The study found a rhombohedral and tetragonal phase coexistence region, where the tolerance factor value of ceramics is between 0.7530 and 0.7803. Moreover, the energy storage density of antiferroelectric ceramics increases with the expansion of the MPB region and is affected by the dielectric constant. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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8. Influence of doping mode on phase structure and electrical properties of antiferroelectric ceramics.
- Author
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Yongfeng Wang, Jing Cao, Zhao Li, and Kunyao Wu
- Subjects
DOPING agents (Chemistry) ,FERROELECTRIC ceramics ,CERAMIC materials ,CERAMICS ,LEAD zirconate titanate ,ENERGY storage ,DIELECTRIC properties - Abstract
The ferroelectric, lead-free perovskite sodium bismuth titanate-barium titanate (BNT-BT) has excellent electrical performance and is now recognized as a possible alternative material for lead zirconate titanate (PZT). It can be doped with some active elements to form a solid solution with a morphotropic phase boundary (MPB), where the solid solution has high dielectric properties and high energy storage performance. In this paper, the research results of BNT-BLT, BNT-BLZT, BNT-BSLZT, BNTBMNLT and BNT-BST-KNN ceramic materials are summarized, and the influence of their doping mode on the phase structure and electrical properties are analyzed. The study found a rhombohedral and tetragonal phase coexistence region, where the tolerance factor value of ceramics is between 0.7530 and 0.7803. Moreover, the energy storage density of antiferroelectric ceramics increases with the expansion of the MPB region and is affected by the dielectric constant. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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9. Low-temperature sintering and piezoelectric properties of Na2O excess (Na0.52K0.44Li0.04)(Nb0.88Sb0.08 Ta0.04)O3 ceramics.
- Author
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Jin, Weiwei, Lv, Danya, Wu, Weiya, and Fan, Chenli
- Subjects
CERAMICS ,SINTERING ,DIELECTRIC properties ,PIEZOELECTRIC ceramics ,LEAD titanate ,TANTALUM ,MICROSTRUCTURE ,TEMPERATURE effect - Abstract
This paper presents the application of an ordinary sintering process for 3 h in air to fabricate highly dense (Na
0.52 K0.44 Li0.04 )(Nb0.88 Sb0.08 Ta0.04 )O3 (NKN-LST) ceramics with excellent piezoelectric properties at a lower sintering temperature through the use of excess Na2 O as a sintering aid. The effects of sintering temperature in the range 940–1100 °C and Na2 O addition in the range of 0 to 3.0 mol% on the density, sintering behavior, microstructure, dielectric and piezoelectric properties of the NKN-LST ceramics are investigated. Analysis reveals that NKN-LST ceramics samples sintered at 1020 °C for 3 h in air with 1.5 mol% excess Na2 O achieve the highest electromechanical coupling factor and piezoelectric coefficient values of 0.45 and 364 pC/N, respectively. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
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10. Effect of boron doping on energy storage performance of PLZST ceramics.
- Author
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Chen, Hong, Chen, Hongwei, Gao, Libin, Deng, Bowen, and Zhang, Jihua
- Subjects
ENERGY storage ,FERROELECTRIC thin films ,PHASE transitions ,CERAMICS ,THICK films ,ENERGY density ,DIELECTRIC properties ,LEAD titanate - Abstract
In this paper, thick film antiferroelectric ceramics (1-x)(Pb
0.97 La0.02 )(Zr0.46 Sn0.48 Ti0.06 )O3 -xH3 BO3 ((1-x)PLZST-xH3 BO3 , x = 0–0.025) were prepared by solid state sintering and tape-casting method. The effects of boron-doping on the microstructure, dielectric properties and energy storage properties of (1-x)PLZST-xH3 BO3 ceramics were investigated. Appropriate boron-doping can improve the stability of antiferroelectric phase, delay phase transition and increase saturation polarization strength. Compared with the undoped PLZST thick films, the maximum polarization intensity increased by 1.9 times and the residual polarization decreased by 37%. When x = 0.020, the maximum recoverable energy storage density is 2.74 J/cm3 , and the energy storage efficiency is 88.12%. [ABSTRACT FROM AUTHOR]- Published
- 2022
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11. Mathematical simulation for the formulation of synthesis of PMN-PZN ceramics at different sintering temperature with reliability of density measurement.
- Author
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Takarkhede, Mamta V., Modak, Jayant P., Band, Sheela. A., Parakhi, Prerana M., and Bhoyar, Leena C.
- Subjects
CERAMICS ,SINTERING ,MATHEMATICAL models ,DENSITY ,DATABASES ,TEMPERATURE ,CERAMIC capacitors ,DIELECTRIC properties - Abstract
This paper discusses the approach to formulate mathematical model (MM) for synthesis of any ceramic and to decide reliability of density measurement. In the research of basic science, the majority of operations are still executed manually which needs to be focused and develop a mathematical relation which simulate the real input and output data directly. The advantages and limitations of the developed mathematical models are identified and the models are classified in terms of range of application and goals. In this study, a generalized experimental data based model developed to simulate the contemporary techniques for the purpose of study, compression, inducing generalized approach for the mathematical model of ceramic synthesis. The findings indicate that the topic understudy is of great importance, as no such approach of experimental data based mathematical simulation is adopted for the formulation of synthesis of ceramics so far. Thus the results of this experimental research would be useful to industry for manufacturing of multilayer capacitors. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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12. Microwave sintering of MnO2 added potassium sodium niobate ceramics and studies of their electrical properties.
- Author
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Monika Aniz, Irom and Maisnam, Mamata
- Subjects
POTASSIUM niobate ,MICROWAVE sintering ,SINTERING ,PERMITTIVITY ,DIELECTRIC properties ,DIELECTRIC loss ,CERAMICS - Abstract
MnO
2 added potassium sodium niobate (KNN) electroceramics were prepared by conventional double sintering ceramic route. The samples prepared have the compositional formula K0.5 Na0.5 NbO3 + (x)MnO2 where x = 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt% and 25 wt% is the amount of MnO2 added. The sintering of the samples was done using the microwave sintering technique. Pre-sintering was done at 850 °C for 20 min. Different sintering conditions may results in KNNs with varied properties. The studies of the structural properties of the prepared samples were done by X-ray diffraction (XRD) technique. It has been found that addition of MnO2 to KNNs and sintering at 1000 °C for 20 min and at 1050 °C for 10 min showed all the KNNs crystallization in tetragonal phase with nearly similar structural parameters. The electrical properties such as dielectric constant, dielectric loss and ac conductivity of the prepared samples were investigated using an impedance analyzer. The room temperature frequency variation of electrical properties showed a dispersive behavior for all the samples. The temperature variation of the dielectric properties showed an increase with the increase of temperature. The results of the various measurements are discussed in the paper. [ABSTRACT FROM AUTHOR]- Published
- 2022
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13. Effect of Sr doping on the energy storage properties of BNT–BST–KNN anti-ferroelectric ceramics.
- Author
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Qi, Wu, Cao, Jing, Li, Zhao, and Wang, Yongfeng
- Subjects
ENERGY storage ,LEAD-free ceramics ,ANTIFERROELECTRIC materials ,DOPING agents (Chemistry) ,CERAMICS ,HYSTERESIS loop - Abstract
(1−x)Bi
1/2 Na1/2 TiO3 –xBa1/2 Sr1/2 TiO3 –0.05KNaNbO3 (BNT–BST–KN, x = 0.01, 0.03, 0.05, 0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The hysteresis loop of the ceramic at different temperature under 70 kV/cm electric field was analyzed. In this paper, the energy storage properties of BNT–BST–KNN ceramics are studied. It was found that the addition of Sr element helps to improve the electric field strength tolerance and the breakdown resistance performance the material, so as to improve its energy storage density. At room temperature, the P–E curves of the materials in the system basically show a double hysteresis loop, and with the increase of temperature, the characteristics of the double hysteresis curve are particularly obvious. The ceramics exist in the ferroelectric–antiferroelectric coexistence phase region near 303 K, namely the morphotropic phase boundary region. It shows that the ceramic has anti-ferroelectric characteristics at room temperature, and is a typical anti-ferroelectric material. [ABSTRACT FROM AUTHOR]- Published
- 2021
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14. Effect of Sr doping on the energy storage properties of BNT-BST-KNN anti-ferroelectric ceramics.
- Author
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Wu Qi, Jing Cao, Zhao Li, and Yongfeng Wang
- Subjects
ENERGY storage ,LEAD-free ceramics ,ANTIFERROELECTRIC materials ,DOPING agents (Chemistry) ,CERAMICS ,HYSTERESIS loop - Abstract
(1-x)Bi
1/2 Na1/2 TiO3 -xBa1/2 Sr1/2 TiO3 -0.05KNaNbO3 (BNT-BST-KN, x = 0.01, 0.03, 0.05, 0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The hysteresis loop of the ceramic at different temperature under 70 kV/cm electric field was analyzed. In this paper, the energy storage properties of BNT-BST-KNN ceramics are studied. It was found that the addition of Sr element helps to improve the electric field strength tolerance and the breakdown resistance performance the material, so as to improve its energy storage density. At room temperature, the P-E curves of the materials in the system basically show a double hysteresis loop, and with the increase of temperature, the characteristics of the double hysteresis curve are particularly obvious. The ceramics exist in the ferroelectric-antiferroelectric coexistence phase region near 303 K, namely the morphotropic phase boundary region. It shows that the ceramic has anti-ferroelectric characteristics at room temperature, and is a typical anti-ferroelectric material. [ABSTRACT FROM AUTHOR]- Published
- 2021
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15. Local polarization reversal in barium titanate single crystals and ceramics.
- Author
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Abramov, A. S., Gimadeeva, L. V., Alikin, D. O., Hu, Q., Wei, X., and Shur, V. Ya
- Subjects
SINGLE crystals ,ATOMIC force microscopes ,FERROELECTRIC ceramics ,CERAMICS ,BARIUM titanate ,PIEZORESPONSE force microscopy - Abstract
Ex-situ local switching is a useful method for studying the domain structure evolution during polarization reversal in the individual grains of the ferroelectric ceramics. In this paper, the local switching by a biased tip of atomic force microscope was studied in the single crystals and ceramics of barium titanate BaTiO
3 (BTO). The initial domain structure in BTO crystal was also studied. The domain growth during local switching in the crystal and individual grains of ceramics was characterized in terms of the parameters of the domain wall motion. [ABSTRACT FROM AUTHOR]- Published
- 2021
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16. Enhanced electrical properties by optimizing sintering temperature and dwell time in BiFe0.96Zn0.02Ti0.02O3 ceramics.
- Author
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Zhang, Guang-Yuan, Dai, Jian-Qing, and Li, Xiao-Ya
- Subjects
CERAMICS ,CRYSTAL structure ,COMPLEX numbers ,LEAD-free ceramics ,SOL-gel processes ,GRAIN size ,SINTERING - Abstract
In this paper, effects of sintering temperature (T
s ) and dwell time (td ) on crystalline structure, microstructure and electrical properties (dielectric and ferroelectric) of BiFe0.96 Zn0.02 Ti0.02 O3 (BFZTO) ceramics synthesized by sol-gel method were investigated. The crystalline structure of BFZTO ceramics remained unchanged with different sintering conditions. The microstructure of BFZTO ceramics have an evident modification by changing sintering temperature and dwell time. With increasing Ts or td , grains of samples become larger. Because of the differences of sintering pross, The large grains and low porosity led to the alignment of the dipole, the low coercive field (Ec of ca. 12 kv/cm), low leakage current density (10−1 μA/cm) and good remnant polarization (Pr of ca. 1.2 μC/cm2 ) were achieved in BFZTO ceramics at Ts = 800 °C, td = 1 h. While the excessive Ts or td resulted in lower number of defect complexes, which had significant influence on ferroelectric properties. The work reported herein demonstrated that the porosity, grain size and the presence of defect complexes have a big part in determining ferroelectric properties of BFZTO ceramics. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
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17. Converse piezoelectric properties of lead free Ba1-xCaxZr0.1Ti0.9O3 (x = 0.055) ceramics using double sintered method.
- Author
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Biswas, Don, Panwar, N. S., and Sharma, Prolay
- Subjects
CERAMICS ,ALKALINE earth metals ,LEAD oxides ,ELECTRIC fields ,GRAIN size - Abstract
The influence of double sintering temperature on the phase structure, micro-structure and piezoelectric properties of Ba
1-x Cax Zr0.1 Ti0.9 O3 (x = 0.055) double sintered ceramics has been systematically studied. The pellet sample preparation and characterization have been reported in this paper. The converse piezoelectric properties of the Ba1-x Cax Zr0.1 Ti0.9 O3 (x = 0.055) were observed. Depending upon the sintering temperature, the grain size and density of BCZT ceramics have been changed. The P-E loops, strain%, and the polarization current were measured. The value of d33 was decreasing with the application of an electric field in case of double sintered pellets. For sample x = 0.055, the value of d33 * at 1300, 1400 and 1450° C temperature, was 173 (pm/V), 130 (pm/V), and 75 (pm/V), respectively, at applied field 29.33 kV/cm. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
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18. Effect of pore former sucrose on microstructure and electrical properties of porous BZT-0.5BCT ceramics.
- Author
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Abhinay, S., Dixit, P., and Mazumder, R.
- Subjects
CERAMICS ,POLYVINYL alcohol ,SUCROSE ,DIELECTRIC properties ,POROSITY ,MICROSTRUCTURE - Abstract
The present paper aims to study the effect of different pore forming agent on the density, porosity, pore morphology and electrical properties of porous BZT-0.5BCT ceramics. The electrical property evaluation is focused on dielectric constant, ferroelectric properties (P-E loop) and piezoelectric constant (d
33 and g33 ) of the porous BZT-0.5BCT ceramics. BZT-0.5BCT powder was prepared by solid-state route. The porous ceramic was prepared by mixing BZT-0.5BCT with different percentage (10, 20, 30, 40 and 50 vol%) of polyvinyl alcohol (PVA) and sucrose as pore-forming agents (PFA). As a result, density, relative permittivity, remanent polarization and piezoelectric constant decreased linearly with increase in pore former addition. The pores derived from PVA and sucrose as pore former were spherical to irregular in shape. Isolated pores are observed up to 30 vol% of PFA addition and pore interconnectivity is observed at 40 vol% of PVA and sucrose addition. The decrease in electrical properties is much higher in sucrose when compared with PVA as a pore former. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
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19. Dielectric and piezoelectric properties of (Na0.52K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3 ceramics substituted with (Bi0.5Na0.5)0.9(Sr)0.1ZrO3
- Author
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Yoo, Ju-Hyun
- Subjects
DIELECTRIC properties ,PIEZOELECTRIC actuators ,TANTALUM ,PIEZOELECTRIC ceramics ,CERAMICS ,BISMUTH ,QUALITY factor - Abstract
In this paper, in order to develop the composition ceramics for piezoelectric actuator, (1-x)(Na
0.52 K0.443 Li0.037 )(Nb0.883 Sb0.08 Ta0.037 )O3 - x(Bi0.5 Na0.5 )0.9 (Sr)0.1 ZrO3 ceramics were synthesized by the conventional solid state method and their piezoelectric and dielectric properties were systematically investigated. All specimens showed a typical pure perovskite structure and no secondary phase was found according to the (Bi0.5 Na0.5 )0.9 (Sr)0.1 ZrO3 substitution. When x = 0.03, the excellent physical properties of d33 = 256pC/N εr = 1753, kp = 0.411, Qm = 58 and high Tc of 285 °C were obtained for piezoelectric actuator. [ABSTRACT FROM AUTHOR]- Published
- 2019
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20. The effect of piezoelectric ceramic volume fraction on the thickness vibration characteristics of 1-3 piezocomposites.
- Author
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Li, Xing, Wang, Likun, Zhong, Chao, and Zhang, Yanjun
- Subjects
PIEZOELECTRICITY ,COMPOSITE materials ,CERAMICS ,VIBRATION (Mechanics) ,TRANSDUCERS - Abstract
The thickness vibration mode of the piezoelectric composite is the most common operation mode in transducer applications. The study on the thickness vibration characteristics plays a key role in application.In this paper, the influence of volume fraction of piezoceramic on the thickness vibration characteristics of 1-3 piezoelectric composites was investigated. Through finite element analysis and simulation, the relationship between vibration performance parameters and the ceramic volume fraction of composites was obtained. The samples with volume fraction of 0.2 ∼ 0.6 were prepared by cutting and filling and tested by Impedance Analyzer.Experimental and simulation results were matched by comparison. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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21. Meso-kinetics of one time relaxation electrical processes in BaTiO3 ceramics—modified Boltzmann-Poisson model.
- Author
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Vosika, Zoran B., Mitić, Vojislav V., Lazović, Goran, Paunović, Vesna, and Kocić, Ljubiša
- Subjects
CERAMICS ,BARIUM titanate ,CHEMICAL relaxation ,DISTRIBUTION (Probability theory) ,BROWNIAN motion ,APPROXIMATION theory - Abstract
This paper is focused on the research an improved version of the Boltzmann-Poisson model for BaTiO
3 -ceramics. In the approximation of one relaxation time, for constant external electrical field, this approach included correct quadratic relation for varistor effect in the case of the Heywang model. Within meso-kinetics, quantum corrected Boltzmann-Poisson model, contains space-time correlations for the probability distribution density function f(r, k, t), lead to correct fractional relaxation velocity description. These new results corresponds to our other research based on electronic particles Brownian motion within its fractal nature. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
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22. Charge-Discharge Properties of PLZT x/90/10 Ceramics.
- Author
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Wawrzała, P. and Korzekwa, J.
- Subjects
FERROELECTRIC ceramics ,ELECTRIC discharges ,LEAD zirconate titanate ,ENERGY storage ,CERAMIC capacitors ,ANTIFERROELECTRIC materials ,PEROVSKITE ,SOLID solutions - Abstract
This paper presents the results of investigations of the ceramic samples of perovskite type solid solution (Pb1-xLax)(Zr1-yTiy)O3(PLZT—with x = 0.02, 0.03, 0.06 and 0.10, y = 0.9). Ceramic samples have been obtained from oxides using classical ceramic technology. The main aim of this paper is to compare the energy storage densities calculated from the P-E loops (at frequency of 1Hz) obtained as a result of integrating the area enclosed by E-P curve for tree types of ceramics—ferroelectric (PLZT with x = 0.02), slim-loop antiferroelectric (PLZT with x = 0.6, 0.10) and normal antiferroelectric with double loops (PLZT with x = 0.03). [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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23. Impedance Spectroscopy of BaBi 2 Nb 2 O 9 Ceramics.
- Author
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Adamczyk, M., Kozielski, L., and Pilch, M.
- Subjects
IMPEDANCE spectroscopy ,BARIUM compounds ,CERAMIC materials ,DIELECTRICS ,RELAXATION phenomena ,CRYSTAL grain boundaries ,ACTIVATION (Chemistry) ,SINTERING - Abstract
Investigations presented in the present work are concerning the other member of the Aurivillius family, the BaBi2Nb2O9 (BBN). This compound, which seems to be very interesting from the potential applications point of view. The dielectric characterization of this materials and influence of sintering condition on grain structure and properties of those materials had been very widely described in our previous paper. Now we would like to present the hitherto unreported electric properties of BaBi2Nb2O9 ceramics, investigated by the impedance spectroscopy (IS). IS is nondestructive method, which allows to separate grain and grain – boundary effects due to the different frequencies of the relaxation process in grain and grain boundaries. This enables us to determine the temperature dependences of grain (Rg) and grain-boundary (Rgb) resistance and evaluate their respective activation energies (Ea). Additionally a comparison between macroscopic results obtained by Impedance Spectroscopy and miroscopic direct local LC-AFM conductivity measurements are presented. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
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24. Electron Transfer Between Ionized Vacancies in Lead Zirconate Titanate and its Effects on Piezoelectric Properties and Squeeze Behavior.
- Author
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Eyraud, Lucien, Lebrun, Laurent, Audigier, David, Guiffard, Benoit, and Guyomar, Daniel
- Subjects
CERAMICS ,PEROVSKITE ,TITANATES ,CHARGE exchange ,PIEZOELECTRICITY ,VALENCE (Chemistry) ,IONIZATION (Atomic physics) ,SEMICONDUCTOR doping - Abstract
Intrinsic double ionized lead vacancies and oxygen vacancies simultaneously exist within PZT compositions and create a defect dipole. Acceptor dopants with a valence of +3 induce extrinsic single ionized oxygen vacancies whereas donor dopants with a valence of +5 induce extrinsic single ionized lead vacancies. An electron exchange can exist between single and double ionized vacancies that it was facilitated in the case of single ionized lead vacancies. As a consequence, such a transfer occurred mainly for soft PZT and almost never for hard PZT. Based on this transfer, this paper explains the softening effect and the squeeze ignition mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
25. Induced Phase Transitions of Functional Ceramics: Properties and Applications.
- Author
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Yong-Ling Wang and Xian-Lin Dong
- Subjects
FERROELECTRIC crystals ,CERAMICS ,FERROELECTRICITY ,ELECTRIC fields ,PHASE transitions ,POLARIZATION (Electricity) ,TEMPERATURE - Abstract
This paper reviews the spontaneous polarization of ferroelectric ceramics and its variations with applied electric field, stress and temperature, especially at induced phase transitions. Normally, there are two kinds of field dependence of the induced polarization, the linear and nonlinear dependence. In this paper the nonlinear relationship will be emphasized. The application of these ceramics for underwater transducers, shock wave power generators, pyroelectric energy converters and pyroelectric voltage transformers are listed. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
26. 0.75(Bi 1/2 Na 1/2 )TiO 3 -0.20(Bi 1/2 K 1/2 )TiO 3 -0.05BaTiO 3 Lead-Free Ceramics with Addition of CeO 2.
- Author
-
Choy, S. H., Wang, X. X., Chan, H. L. W., and Choy, C. L.
- Subjects
CERAMICS ,PIEZOELECTRIC ceramics ,PIEZOELECTRICITY ,ENERGY dissipation ,PIEZOELECTRIC materials - Abstract
Lead-free piezoelectric 0.75(Bi 1/2 Na 1/2 )TiO 3 -0.20(Bi 1/2 K 1/2 )TiO 3 -0.05BaTiO 3 ceramics(abbreviated as BNKBT-20) with addition of 0.2, 0.4, 0.6 and 0.8 wt% of CeO 2 , respectively, were prepared by a conventional mixed oxide method. The addition of CeO 2 can reduce the dissipation factor and enhance the mechanical quality factor significantly. The composition with 0.4 wt% CeO 2 has a piezoelectric d 33 constant of 129 × 10 - 12 C/N and a relatively low dissipation factor (tan δ = 1.8%) at 1 kHz which shows a 50% reduction in the dissipation factor when compared with BNKBT-20 before doping (tan δ = 3.74%). [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
27. Performance of K 0.5 Na 0.5 NbO 3 -LiSbO 3 -CaTiO 3 ceramics in acoustic energy harvesting exposed to sound pressure.
- Author
-
Kumar, Anuruddh, Sharma, Anshul, Kumar, Rajeev, Vaish, Rahul, and Bowen, C. R.
- Subjects
STRAINS & stresses (Mechanics) ,ACOUSTIC radiation pressure ,CERAMICS ,ENERGY harvesting ,SOUND pressure - Abstract
In this paper, a numerical investigation is carried out for K0.5Na0.5NbO3-LiSbO3-CaTiO3ceramics for harvesting low frequency sound. For the numerical simulation, a quarter wavelength straight tube resonator with a rectangular cross section was modelled and piezoelectric laminated cantilever bimorph plates placed inside the system at uniform distance. With the application of acoustic sound pressure of a resonant frequency at the opening of tube resonator, the amplified acoustic pressure inside the tube vibrates piezolaminated bimorph plates placed inside the tube, thus generating a voltage on the surface of the piezoelectric layer. In order to generate more voltage and power in the acoustic harvesting system, multiple piezolaminated cantilever plates are placed inside the straight tube resonator. The lead-free piezoelectric material of K0.5Na0.5NbO3(KNN) family i.e. K0.5Na0.5NbO3-LiSbO3-(2wt %) CaTiO3(KNN-LS-CT) was explored as a piezoelectric material for the acoustic energy harvesting system. With the application of acoustic sound pressure of 1dB at the opening of the tube, an output voltage of maximum 3.8 V is measured numerically at resonant frequency of 194 Hz while the maximum power calculated is 2 µW. The numerical results reveal the potential of the lead-free piezoelectric materials for acoustic energy harvesting applications. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
28. Phase transitions, magnetic and dielectric properties of PbFe 0.5 Nb 0.5 O 3.
- Author
-
Abdulvakhidov, K. G., Ubushaeva, E. N., Mardasova, I. V., Vitchenko, M. A., Abdulvakhidov, B. K., Zaletov, V. G., Amirov, A. A., Kamilov, I. K., Manukyan, A. S., Plyaka, P. S., and Sukharina, G. B.
- Subjects
PHASE transitions ,MAGNETIC properties ,DIELECTRIC properties ,FERROELECTRIC materials ,X-ray diffraction ,MAGNETIC moments - Abstract
In this paper the investigation of relaxor ferroelectric PbFe0.5Nb0.5O3has been carried out using the method of X-ray diffraction, magnetic and dielectric measurements over a wide range of temperatures and frequencies. It has been shown that in single crystals there is high-temperature phase transition from the ferroelectric phase to the cubic phase at a temperature of 367 K. The anomalies detected in the dependences of magnetic susceptibility χ (T) and the magnetic moment m (T) in polycrystalline at room temperature and above were found to be correlating with the anomalies detected by structural, EPR spectroscopic and dielectric measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
29. Study on milling time and calcining temperature of A-site-doped BNT-BLT anti-ferroelectric ceramics.
- Author
-
Wang, Yongfeng, Cao, Jing, and Li, Zhao
- Subjects
CERAMICS ,CALCINATION (Heat treatment) ,LEAD-free ceramics ,X-ray diffraction ,TEMPERATURE ,MICROSTRUCTURE - Abstract
[(Bi
1/2 Na1/2 )0.94 Ba0.06 ]0.97 La0.02 TiO3 (BNT-BLT) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state.By analyzing TGA and DSC curves, the material should be calcined at about 800 °C. The effects of different milling time on the microstructure of the materials were also studied. Microstructures analysis and the calculation from the X-ray diffraction results reveal that the milling time of BNT-BLT ceramic should be controlled within a reasonable range, around 15 h. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
30. Impedance spectroscopy and conductivity studies of Sr(Bi3.9-xNdxLa0.1)(Ti3.975Zr0.025)O15 (x = 0.00, 0.025, 0.05, 0.075 and 0.1) ceramics.
- Author
-
Mamatha, B. and Ashok, K.
- Subjects
IMPEDANCE spectroscopy ,CERAMICS ,X-ray diffraction ,SCANNING electron microscopy - Abstract
Sr(Bi
3.9-x Ndx La0.1 )(Ti3.975 Zr0.025 )O15 (x = 0.00, 0.025, 0.05, 0.075 and 0.1) ceramics were prepared by solid-state reaction technique. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectra (EDS). The impedance spectroscopy and conductivity studies were investigated. XRD analysis indicated, the formation of a single-phase orthorhombic structure and particle size was found by SEM. The compositions were confirmed from their EDS spectra. Impedance plots were used as tools to analyze the sample behavior as a function of frequency and temperature. Cole-Cole plots were showed that a non-Debye relaxation. Conductivity measurements were performed on it. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
31. Influence of thermal cycling rate and sintering temperature of barium titanate and barium strontium titanate ceramics on their dielectric properties.
- Author
-
Semenov, Alexander, Mylnikov, Ivan, Es'kov, Andrey, Anokhin, Alexander, Pavlova, Yulia, Dedyk, Antonina, and Kholkin, Andrei
- Subjects
BARIUM strontium titanate ,CERAMICS ,BARIUM titanate ,STRONTIUM titanate ,DIELECTRIC properties ,THERMOCYCLING ,PYROELECTRICITY ,FERROELECTRICITY - Abstract
One of the negative effects of ferroelectric applications, particularly for electrocaloric effect (ECE) applications, is temperature hysteresis (ΔT
Hyst ). Temperature hysteresis is the difference between the temperatures corresponding to the maximum dielectric permittivity in heating and cooling modes. The value of ΔTHyst is commensurate with the value of the ECE temperature change. The ECE is a phenomenon in which a material shows a reversible temperature change under an applied electric field. The aim of this work is to study the possibilities of temperature hysteresis reduction by varying the ceramic sintering temperature, changing the stoichiometry of Bax Sr1-x TiO3 solid solutions, and changing the rate of the heating-cooling cycle. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
32. Magnetoelectric Effect in (0–3) CoFe 2 O 4 -BaTiO 3 (20/80) Composite Ceramics Prepared by the Organosol Route.
- Author
-
Etier, Morad, Shvartsman, Vladimir V., Gao, Yanling, Landers, Joachim, Wende, Heiko, and Lupascu, Doru C.
- Subjects
BARIUM titanate ,CERAMICS ,MAGNETOELECTRIC effect ,COBALT compounds ,IRON oxides ,CRYSTALLIZATION ,PRECIPITATION (Chemistry) - Abstract
In this paper we report on a new approach to synthesize core/shell cobalt iron oxide/barium titanate composite nanoparticles combining the co-precipitation and organosol crystallization techniques. The weight fraction of CoFe2O4and BaTiO3was 20% and 80% respectively. The obtained core/shell powder was used to sinter (0-3) composite multiferroic ceramics. Ferroelectric, magnetic, and magnetoelectric properties of the ceramics were studied. It was found that the value of the converse magnetoelectric coefficient, αc, reaches 4.4·10−12s·m−1at the magnetic fieldμ0Hdc= 0.15 T andT= 285 K. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
33. Microstructure and Dielectric Properties of Bismuth Copper Tantalate as Internal Barrier Layer Capacitor Ceramic.
- Author
-
Szwagierczak, D. and Kulawik, J.
- Subjects
CERAMIC capacitors ,MICROSTRUCTURE ,DIELECTRICS ,BISMUTH compounds ,TANTALATES ,CRYSTAL grain boundaries ,IMPEDANCE spectroscopy ,SINTERING ,PEROVSKITE synthesis - Abstract
The paper presents synthesis, sintering procedure, microstructure and dielectric properties of a new high permittivity perovskite material relative to Cu2Ta4O12, with the composition Bi2/3CuTa4O12. Impedance spectroscopic studies carried out at frequencies 10 Hz–2 MHz and in a temperature range –55 to 740°C revealed two dielectric responses. The high-frequency and low-temperature response was attributed to grains, and the low-frequency and high-temperature one - to grain boundaries. The high dielectric permittivity was suggested to be related to spontaneous formation of internal barrier layers at the grain boundaries of the semiconducting grains. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
34. Structural, Dielectric and Pyroelectric Properties of Praseodymium Based Complex Tungsten Bronze Ferroelectrics.
- Author
-
Padhee, R., Das, Piyush R., Parida, B. N., and Choudhary, R. N. P.
- Subjects
PRASEODYMIUM ,PYROELECTRICITY ,COMPLEX compounds ,TUNGSTEN bronze ,FERROELECTRIC crystals ,ELECTRIC properties of materials ,TEMPERATURE effect - Abstract
This paper highlights the structural, dielectric and pyroelectric properties of two complex tungsten bonze ceramics (K2Pb2Pr2W2Ti4Nb4O30and K2Pb2Pr2W2Ti4Ta4O30) which were prepared by high temperature mixed oxide method. Room temperature X-ray structural analysis confirms the formation of the compounds in single phase. SEM micrographs show uniform distribution of densely packed rod like grains. Variation of dielectric parameters with temperature and frequency shows the phase transition at 350°C and 426°C for the respective samples. Temperature dependent hysteresis loop confirms the existence of ferroelectricity in the materials. The current variation with voltage at different temperatures shows the semiconductor like behaviour of the materials. The temperature dependent dc conductivity follows the Arrhenius equation, and reveals the negative temperature coefficient of resistance (NTCR) behaviour of the materials. The current (for a fixed voltage) variation with temperature shows that the materials have high pyroelectric co-efficient and figure of merit, thus making them useful for pyroelectric sensors. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
35. Dielectric Properties and AC Conductivity of Ag(Ta,Nb)O 3 Ceramics.
- Author
-
Lee, Ku-Tak and Koh, Jung-Hyuk
- Subjects
CERAMICS ,DIELECTRICS ,ALTERNATING currents ,SILVER oxide ,X-ray diffraction ,ELECTRIC conductivity ,RELAXATION (Nuclear physics) ,PERMITTIVITY - Abstract
The ac conductivity and relaxation mechanism in Ag(Ta,Nb)O3 ceramics have been investigated systematically. The formation of the ceramics was checked by an X-ray diffraction (XRD) technique analysis. The dielectric permittivity and the loss tangent of the Ag(Ta,Nb)O3 specimen were measured in a frequency range from 1 to 100 kHz at the various temperature ranges (30–110°C). A study on dielectric properties reveals the electrical relaxation phenomenon occurs in the material. Studies on the frequency and temperature dependence of ac conductivity of the Ag(Ta,Nb)O3 ceramics suggest that conduction process in the material is thermally activated process. In this paper, we will discuss the dielectric properties and the ac conductivities of Ag(Ta,Nb)O3 ceramics in relation to the electrical conduction process. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
36. Electronic ceramics fractal microstructure analysis - Minkowski Hull and grain boundaries.
- Author
-
Mitic, Vojislav V., Lazovic, Goran, Paunovic, Vesna, Veljkovic, Sandra, Randjelovic, Branislav, Vlahovic, Branislav, and Fecht, Hans
- Subjects
ELECTRONIC ceramics ,CRYSTAL grain boundaries ,FRACTAL analysis ,FRACTALS ,DIELECTRIC properties ,GEOMETRIC surfaces ,CERAMIC materials ,MICROWAVE sintering - Abstract
Consolidation parameters have influence and can be used to control structure of BaTiO
3 based materials. Microstructure and dielectric properties of Yb2 O3 doped BaTiO3 -ceramics, sintered from 1320 °C to 1380 °C have been investigated. The correlation between microstructure, capacity and dielectric properties of doped BaTiO3 -ceramics, based on fractal geometry and micro-contact surfaces, has been developed. Using the fractal descriptors of the grains contact surface, the microstructure reconstruction constituents, as grains and pores shapes or intergranular contacts, has been successfully done. Obtained results indicated that fractal analysis contact surfaces descriptors of different shapes are very important for the prognosis of BaTiO3 -ceramics microstructure and capacity and dielectric properties. The morphology of ceramics grains pointed out the validity of developing new structure analytical methods, based on different grains' shape geometries. The grains contact structure based on Minkowski hull is presented as a new tool for BaTiO3 -ceramics materials structure research. The materials properties prognosis are determined according to the correlations synthesis–structure–property, within Minkowski hull fractal frame. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
37. Concurrent Artificial Neural Network Modeling of Single-Crystal and Bulk-Ceramics Ferroelectric-Hysteresis: An Application to Barium Titanate.
- Author
-
Laosiritaworn, Wimalin, Wongdamnern, Natthapong, Yimnirun, Rattikorn, and Laosiritaworn, Yongyut
- Subjects
ARTIFICIAL neural networks ,CRYSTALS ,CERAMICS ,FERROELECTRICITY ,HYSTERESIS ,BARIUM compounds ,COMPUTER simulation - Abstract
This paper proposed an application of Artificial Neural Network (ANN) to concurrently model ferroelectric hysteresis properties of Barium Titanate in both single-crystal and bulk-ceramics forms. In the ANN modeling, there are 3 inputs, which are type of materials (single or bulk), field amplitude and frequency, and 1 output, which is hysteresis area. Appropriate number of hidden layer and hidden node were achieved through a search of up to 2 layers and 30 neurons in each layer. After ANN had been properly trained, a network with highest accuracy was selected. Query file of unseen input data was then input to the selected network to obtain the predicted hysteresis area. From the results, the target and predicted data were found to match very well. This therefore suggests that ANN can be successfully used to concurrently model ferroelectric hysteresis property even though the considered ferroelectrics are with different domains, grains and microscopic crystal structures. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
38. Microwave Property of Low-Temperature-Sintered Ba1-xSrxTiO3 Ceramics with B-Li Glass Sintering Aid.
- Author
-
Jiang, Haitao, Zhai, Jiwei, Chou, Xiujian, and Yao, Xi
- Subjects
MICROWAVES ,LOW temperatures ,SINTERING ,BARIUM compounds ,CERAMICS ,MANUFACTURING processes ,MICROSTRUCTURE ,DIELECTRICS - Abstract
This paper reports on fabrication and characterization of low-temperature-sintered barium-strontium titanate (BST) ceramics with B-Li glass as sintering aid. With the addition of B-Li glass, the sintering temperature of BST can be effectively reduced from 1350 to 920°C due to the presence of a liquid phase. The effects of B-Li glass addition on phase composition, microstructure, dielectric properties, and microwave properties of the BST ceramics were sytematically investigated. The sample (Ba0.50Sr0.50TiO3) with 5.0 wt% B-Li sintered at 920°C for 5 h exhibits optimized room temperature dielectric properties, including a moderate dielectric constant (ε = 1051), a low dielectric loss (0.0048) and a high tunability (31%) at dc electric field of 45 kV/cm and 10 kHz. At 1.150 GHz, it possesses a dielectric constant of 695 and Q value of 207. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
39. The Influence of Individual Phases on Piezoelectric Coefficient of PZT-PVdF Composites.
- Author
-
Greeshma, T., Balaji, R., Nayak, M. M., and Jayakumar, S.
- Subjects
POLYMERS ,CERAMICS ,MACROMOLECULES ,PIEZOELECTRIC devices ,PIEZOELECTRICITY - Abstract
The paper details the preparation of PZT-PVdF composites of 50 Vol% with 0-3 connectivity using densified and calcined reinforcement by hot press technique and the analysis of the depoling studies to know the contribution of the individual phases to the piezoelectric charge coefficient. The homogenous distribution of PZT reinforcement in the polymer matrix was confirmed by SEM studies. The composites prepared with densified PZT as reinforcement were found to exhibit higher piezoelectric coefficient when compared to the calcined one. The depoling study reveals that the d33 value in the composites prepared with densified reinforcement is contributed by the ceramic phase and for the composite with calcined reinforcement the polymer alone contributes to the d33 value. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
40. Evaluation of Piezoelectric Properties of Bi4Ti3O12—Based Ceramics at High Temperature.
- Author
-
Villegas, Marina, Caballero, Amador C., Jardiel, Teresa, Aragó, Carmen, Maudes, Jon, and Caro, Iñaki
- Subjects
PIEZOELECTRIC devices ,AUTOMATIC control systems ,AERONAUTICS ,CERAMICS ,DETECTORS - Abstract
Nowadays many industries as aeronautic, aerospace, etc, are claiming for new sensors and actuators that can operate in hostile environments. PZT ceramics are the common materials used in piezoelectric devices, however their low Curie temperature prevents their use at high temperatures. Bi4Ti3O12-based ceramics show a great potential for high temperature applications. Although piezoelectric parameters of BIT ceramics are well described at room temperature, its behaviour at high temperatures is almost lacking. This paper describes an experimental set-up to measure the piezoelectric properties of high temperature piezoceramics up to 700°C. The variation of piezoelectric parameters of W-doped BIT ceramics as a function of temperature indicates that their operating temperature extends up to 500°C, surpassing the expected one (½ Tc) in more than 200°C. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
41. Influence of Porosity on Polarisation and Electrical Properties of Hydroxyapatite Based Ceramics.
- Author
-
GITTINGS, J. P., BOWEN, C. R., DENT, A. C. E., TURNER, I. G., BAXTER, F. R., CARTMELL, S., and CHAUDHURI, J.
- Subjects
POROSITY ,POLARIZATION (Electricity) ,HYDROXYAPATITE ,CERAMICS ,POLYMERS - Abstract
This paper studies the effect of porosity on the electrical properties and polarisation behaviour of hydroxyapatite based ceramics prepared in both dense and porous form. Porosity was introduced into the hydroxyapatite using either burnt-out polymer spheres to produce isolated pores or using polymer foams to create interconnected porosity. The samples were sintered in water vapour at 1300°C and polarised at 400°C with a dc voltage of 3kV/cm applied for 1 hour. Thermally stimulated depolarisation current measurements were used to investigate the degree of polarisation of the hydroxyapatite ceramics and dielectric spectroscopy used to measure the ac conductivity of the materials at the polarisation temperature. The porous materials were successfully polarised and the presence of a high surface area to volume ratio in the porous samples was thought to increase the level of polarisation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
42. Investigation of Different Additive on the Structure and Dielectric Performance of LiNb0.6Ti0.5O3 Ceramic.
- Author
-
LINGXIA LI, YU LIANG, GUOCHAO LI, and PING ZHANG
- Subjects
SINTERING ,CERAMICS ,PROPERTIES of matter ,DIELECTRICS ,NANOSTRUCTURED materials - Abstract
Li(1 + x - y)Nb(1 - x - 3y)Ti(x + 4y)O3 ceramic system has been promising materials for LTCC application for their high dielectric constant, quality factor and low sintering temperature. In this paper, different kinds of additive were added to the so called “M phase” solution to further lower their sintering temperature. The effects of different content of B2O3, LiF on sintering character and microwave dielectric properties of LiNb0.6Ti0.5O3(x = 0.1, y = 0.1) ceramics were investigated as a function of sintering temperature and calcining time. LiF was chosen as compensation to Li loss during calcining and sintering procedure. According to experiment result, properly prolonged calcining time (8-10 h) favored the ordered growth of grain and the improvement of dielectric performance. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
43. Studies of Resistivity and Dielectric Properties of Manganese-Doped Barium Titanate Sintered in Pure Nitrogen.
- Author
-
YANXIA LI, XI YAO, XUSHENG WANG, and LIANGYING ZHANG
- Subjects
DIELECTRICS ,SEMICONDUCTORS ,MICROSTRUCTURE ,CERAMICS ,SINTERING - Abstract
This paper investigated the resistivity and dielectric properties of manganese doped barium titanate sintered in pure nitrogen. The influence of variable doping concentration and Ba/Ti ratio on densification, microstructure, resistivity and dielectric properties was studied. A dielectric with permittivity of 1500 and low dissipation factor of 0.01 measured at 1 kHz, meeting the EIA X7R specification of the Electronic Industries Association standards was obtained in this study. Resistivity of materials sintered in pure nitrogen was 1011∼ 1012Ω cm. Ceramics sintered in pure nitrogen had higher resistivity than ceramics sintered in air, and the resistivity increased with Ba/Ti ratio increasing. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
44. Comparative Analysis of Li2CO3 Doped (Ba,Sr)TiO3 and ZnBO Doped (Ba,Sr)TiO3 Ceramics for the Low Temperature Sintering Applications.
- Author
-
SE-HO KIM, HEE-WOOK YOU, SANG-MO KOO, JAE-GEUN HA, SONG-MIN NAM, JUNG-HYUK KOH, and SOON JONG JEONG
- Subjects
CERAMICS ,SINTERING ,DIELECTRICS ,SEMICONDUCTOR doping ,DIFFUSION - Abstract
For the research on the LTCC(Low Temperature Co-fire Ceramic) applications, low temperature sintered ceramics have been extensively investigated. In this study, we have focused on the Li2CO3 doped (Ba,Sr)TiO3 and ZnBO doped (Ba,Sr)TiO3ceramics which have moderate dielectric properties such as high dielectric permittivity and low loss tangent. Until now, B2O3 has been commonly employed as the low temperature sintering aid. However, in this paper, we suggest Li2CO3 and ZnBO as alternative sintering aids to the B2O3. 1∼5 wt% of Li2CO3 or ZnBO was added to BST ceramics in order to reduce the sintering temperature. Li2CO3 doped BST and ZnBO doped BST ceramics were respectively sintered from 700°C to 1050°C and 750°C to 1250°C by 50°C to confirm the sintering temperature with different dopants concentrations. By adding Li2CO3 to the BST ceramics, the sintering temperature of BST ceramics was drastically lowered down to 900°C, whereas by introducing ZnBO dopants to BST, the loss tangent was decreased. From the XRD analysis, ZnBO doped BST ceramics have no pyro phase. 3 wt% Li2CO3 doped BST ceramics, which sintered at 900°C, have moderate relative dielectric permittivity of 1451 at 1 kHz, while 5 wt% ZnBO doped BST ceramics, sintered at 1100°C, have decreased dielectric permittivity of 1180 at 1 kHz. The loss tangent of ZnBO doped BST was decreased compared with that of BST. The loss tangent of ZnBO (1 wt%) doped BST was decreased down to 2.71 × 10-3 at 1 MHz. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
45. Modulation of Relaxor Behaviour by Chemical Substitution in the System Ba1-xCaxTi1-y(Zn1/3Nb2/3)yO3.
- Author
-
Khemakhem, L., Maalej, A., Kabadou, A., Salah, A. Ben, Simon, A., and Maglione, M.
- Subjects
DIELECTRICS ,ELECTRICAL engineering materials ,CERAMICS ,X-ray diffraction ,FERROELECTRIC crystals - Abstract
This paper reports the structural and dielectric properties of Ba1 - xCaxTi1 - y (Zn1/3Nb2/3)yO3 ceramics with y is fixed to 0.2 and x = 0.2 and 0.3. Single-phase solid solutions of the simples were determined by X-ray diffraction. For the solid solution, BaTi1 - y(Zn1/3Nb2/3)yO3, the evolution of dielectric behaviour from a sharp ferroelectric peak (for y < 0.075) and to ferroelectric relaxor (for 0.075 < y < 0.2) was observed with increasing of Zn and Nb concentration but in this case the temperature of the maximum of dielectric permittivity Tm and Δ Tm are lowers. To modulate this relaxor character we have substitute the Ba by Ca to increase Tm and Δ Tm. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
46. The Influence of DC Electric Field on Piezoelectric Coefficients of PZT Ceramics.
- Author
-
Burianova, L., Panos, S., Hana, P., and Nosek, J.
- Subjects
ELECTRIC fields ,CERAMICS ,PIEZOELECTRIC materials ,FERROELECTRIC crystals ,FERROELECTRICITY - Abstract
The paper deals with the non-linear properties of the piezoelectric ceramics Pb(ZrxTi1 - x)O3 (PZT) at room temperature. The influence of DC electric field on the material parameters, such as piezoelectric coefficients d31 and d33 of PZT ceramics, was studied using the resonance method. The dependence of the resonance and antiresonance frequencies of PZT resonators on DC electric field was measured. Hydrostatic piezoelectric coefficients dh, calculated from d33 and d31 piezoelectric coefficients, were compared with dh coefficients, that were measured directly by dynamic hydrostatic method. Electric field limits for application on PZT ceramics were determined. A remarkable influence of the DC electric field on d31 and d33 piezoelectric coefficients values was exhibited for soft PZT ceramics (APC 850 and APC 856). [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
47. Measurements of Complex Dielectric Constant of Ferroelectrics with Six-port Reflectometer in 80-120 GHz Frequency Range.
- Author
-
Ivanov, M., Banys, J., Rudys, S., and Grigalaitis, R.
- Subjects
DIELECTRIC measurements ,REFLECTOMETER ,ELECTRIC measurements ,CERAMICS ,FERROELECTRIC crystals ,FERROELECTRICITY - Abstract
In the present work six-port reflectometer suitable for the dielectric measurements in the frequency range 80-120 GHz is described. Complex dielectic constant is very difficult to obtain the higher is the value and the higher the frequency of measurements. Presented method is presented with superior calibration method, which implies higher precision. In this paper, results of actual measurements of relaxor ceramics PLZT 8/65/35 and comparison to previous work are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
48. Electron Transfer Mechanism in PZT Ceramics—Application to Squeeze Ignition.
- Author
-
EYRAUD, LUCIEN, GUIFFARD, BENOIT, AUDIGIER, DAVID, LEBRUN, LAURENT, and GUYOMAR, DANIEL
- Subjects
CHARGE exchange ,FERROELECTRIC crystals ,CERAMICS ,CATIONS ,ANIONS - Abstract
The aim of this paper is to clarify the fundamental difference occurring between a soft PZT ceramic and a hard one. The first type presents singly ionised and doubly ionised cation (lead) vacancies and the second one exhibits singly and doubly ionised anion (oxygen) vacancies. In this sense, this work also explains the mechanism that rales piezoelectric igniters and the reason why some materials lead to higher performances. For igniters, two types of systems can be used: the first one corresponds to a slow application of the stress on the piezoelectric element (squeeze) and the second one implies a mechanical shock produced on the element. In the case of “squeeze” igniters, it is clearly evidenced that spark creation only occurs when hard PZTs are used and this effect originates from the crucial role of the effective charge of oxygen vacancies in hard PZTs. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
49. Electrical Investigations of Aurivillius Type Sr0.7A0.3Bi2Nb2O9 (A = Ca, La and Pb) Ferroelectric Ceramics.
- Author
-
Shrivastava, Vaibhav, Jha, A. K., and Mendiratta, R. G.
- Subjects
FERROELECTRICITY ,CERAMICS ,DIELECTRICS ,BISMUTH ,CALCIUM - Abstract
Aurivillius type bismuth layer structured ferroelectrics (BLSF) have been found to possess strong relationship between tetragonal strain (c/a) and extrinsic/ intrinsic conductivity. The extrinsic part of the conductivity is known to depend upon space charge in the sample. The present paper discusses effects of 30 atomic % doping of Ca, La and Pb on tetragonal strain, conductivity and dielectric constant/loss with temperature and frequency. Tetragonal strain increases on doping calcium and lead while it shows a decrease on doping lanthanum. The calcium and lanthanum doped samples show pronounced space charge part of dielectric constant while lead doped sample shows nearly constant permittivity values. No phase transition is observed in the calcium doped sample up to 600°C while for the lanthanum doped sample a decrease of 141°C is observed in the value of Curie temperature compared to that for the undoped sample. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
50. Structure and Properties of Microwave Sintering ZnO Ceramics.
- Author
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Lin Wang, Jian Zhou, Guizhen Liu, Shixi Ouyang, and Hanxing Liu
- Subjects
MICROWAVES ,SINTERING ,ZINC oxide ,CERAMICS ,MORPHOLOGY - Abstract
In this paper, it is investigated the microwave sintering method of ZnO ceramics using pure ZnO powder as raw materials, and then it was successfully sintered with the 2.45GHz microwave sintering technique. The microscopic structure and morphology of ZnO ceramic samples were determined in XRD and SEM, I-V properties are also measured. The results show that microwave sintering method is a rapid sintering method for ZnO ceramic with homogeneous structure and good properties, microwave sintering is a promising method for ZnO ceramics. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
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