scholarly journals NEW LEAD-FREE PEROVSKITE RELAXOR CERAMICS DERIVED FROM BaTiO3 AND CONTAINING SCANDIUM

2011 ◽  
Vol 01 (02) ◽  
pp. 251-255 ◽  
Author(s):  
ANNIE SIMON ◽  
JEAN RAVEZ
Keyword(s):  
Dielectric Properties ◽  
Lead Free ◽  
Relaxor Behavior ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electronic Configurations ◽  
Small Change ◽  
Perovskite Type ◽  
Ferroelectric Transition Temperature

New lead-free compositions of AMO3 perovskite type were synthesized in the BaTi 1-x( Nb 1/2 Sc 1/2)x O 3(0 ≤ x ≤ 1) system, with regards to the comparable electronic configurations of the various 6-coordinated cations. Special solid state reaction was used. The effect of the replacement of titanium by scandium and niobium in the B-site on structural and dielectric properties was investigated. For this, we have used X-ray diffraction and dielectric characterizations. Dielectric measurements performed on ceramics with 0 ≤ x ≤ 0.25 composition revealed that the small change in composition from BaTiO3 has a strong influence on the dielectric properties: fast decreasing of the ferroelectric transition temperature for low values of x and evolution from classical ferroelectric for 0 ≤ x ≤ 0.075 to relaxor behavior for 0.075 < x ≤ 0.25.

Effect of Sintering Temperature on Phase Formation and Dielectric Properties of PLZT-BT Ceramics

2015 ◽  
Vol 1120-1121 ◽  
pp. 7-10
Author(s):  
Ladapak Chumprasert ◽  
Narit Funsueb ◽  
Apichart Limpichaipanit ◽  
Athipong Ngamjarurojana
Keyword(s):  
Dielectric Properties ◽  
Lead Zirconate Titanate ◽  
Sintering Temperature ◽  
Lead Zirconate ◽  
Rhombohedral Structure ◽  
Relaxor Behavior ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Powders

In this research, Barium titanate (BT) additive in lanthanum modified lead zirconate titanate (PLZT) was used to stabilize the PLZT ceramics. Oxide powders were synthesized by mixed oxide synthetic route via a rapid vibro-milling technique. It was prepared with the chemical formula of 0.95 Pb0.91La0.09 (Zr0.65Ti0.35)0.9775O3 -0.05 BaTiO3 to investigate the dielectric properties of PLZT ceramics. The modified PLZT ceramics were fabricated at variation of sintering temperatures of 1200-1275°C for 4 hours. By employing X-ray diffraction (XRD), it was found a pure perovskite with rhombohedral structure. The relaxor behavior was observed from the dielectric measurements. The suitable sintering temperature of 0.95 PLZT - 0.05 BT was 1275°C (εr=10463, tanδ=0.0125 and Tm=70°C).

Dielectric Properties and Raman Spectroscopy in Ca-Substituted Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2011 ◽  
Vol 324 ◽  
pp. 298-301 ◽  
Author(s):  
Roy Jean Roukos ◽  
Olivier Bidault ◽  
Julien Pansiot ◽  
Ludivine Minier ◽  
Lucien Saviot
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Rhombohedral Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray

Lead free Na0.5Bi0.5TiO3 (NBT) and (Na0.5Bi0.5TiO3)1-x(CaTiO3)x (NBT-CT) piezoelectric ceramics with the perovskite structure were studied. The NBT and NBT-CT samples were synthesized using a solid-state reaction method and characterized with X-ray diffraction (XRD), Raman spectroscopy and dielectric measurements for several compositions (x = 0, 0.07, 0.15) at room temperature. The XRD analysis showed a stabilization of a rhombohedral phase at a low concentration of Ca (0 < x <0.15), whereas Raman spectra reveal a strong modification for the sample with x = 0.15. The dielectric properties of these ceramics were studied by measuring impedance in the 79-451K temperature range for unpoled and field cooling with an electric field (FC) conditions.

X-ray powder diffraction and dielectric study of BaTi1−x(Zn1/3Nb2/3)xO3 (x=0.025 and 0.9)

2008 ◽  
Vol 23 (3) ◽  
pp. 241-245
Author(s):  
L. Khemakhem ◽  
A. Kabadou ◽  
A. Ben Salah ◽  
N. Abdelmoula
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Dielectric Study ◽  
Relaxor Behavior ◽  
Dielectric Measurements ◽  
Compound A ◽  
Space Group ◽  
X Ray

Polycrystalline BaTi1−x(Zn1/3Nb2/3)xO3 (x=0.025 and 0.9) compounds were synthesized successfully and studied by XRD and dielectric measurements. The effects of the Ti/(Zn,Nb) ratio on the structure and dielectric properties of the compounds were investigated. XRD results indicated that the crystal structure of the x=0.09 compound is cubic perovskite with space group Pm3m and a=4.0095(4) Å. For the x=0.09 compound, a splitting of the (200) peak was observed near 40.2°, indicating that the crystal structure changed from cubic to tetragonal, with space group P4mm, a=4.026(4) Å, and c=4.0091(4) Å. Rietveld refinement of the crystal structures led to final confidence factors Rp=0.0353 and Rp=0.0349 for x=0.025 and 0.9, respectively. Dielectric measurements showed a relaxor behavior present in BaTi0.1(Zn1/3Nb2/3)0.9.

scholarly journals Dielectric Behaviour of Zn/Al-NO3LDHs Filled with Polyvinyl Chloride Composite at Low Microwave Frequencies

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ethar Y. Salih ◽  
Zulkifly Abbas ◽  
Samer Hasan Hussein Al Ali ◽  
Mohd Zobir Hussein
Keyword(s):  
Dielectric Properties ◽  
Polyvinyl Chloride ◽  
Loss Factor ◽  
Room Temperature ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Microwave Frequencies ◽  
X Ray ◽  
Essential Properties ◽  
Double Hydroxide

Recently, researchers have shown great interest in improving the thermal, mechanical, dielectric, and microwave properties of pure polymers through the use of polymer-based composites. The essential properties of polymer-based composites can be modified by varying the amount of Zn/Al-NO3layered double hydroxide (LDH) added to polyvinyl chloride (PVC). Therefore, by determining the optimal ratio of LDH in the PVC matrix, the dielectric properties of PVC-LDH composites can be improved. An LDH was prepared using the coprecipitation method, while PVC-LDH composites were prepared using tetrahydrofuran (THF) as the solvent. The composites were characterised using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), and room temperature dielectric measurements were investigated using an RF Impedance/Material Analyzer (Agilent 4291). The results confirmed that the prepared composites were pure. Additionally, the presence of LDH in the PVC matrix was verified. The dielectric measurements showed that an increase in the LDH concentration leads to an increase in the dielectric constant and the dielectric loss factor. When used as dielectric filler in the PVC matrix, the LDH improved the dielectric properties of the fabricated composites. The results indicate that these composites show great potential for use as microwave absorbers at low microwave frequencies.

Dielectric properties anomaly of (1−x)Pb(Ni1/3Nb2/3)O3−xPbTiO3 ceramics near the morphotropic phase boundary

2001 ◽  
Vol 16 (3) ◽  
pp. 834-836 ◽  
Author(s):  
Zhenrong Li ◽  
Liangying Zhang ◽  
Xi Yao
Keyword(s):  
Dielectric Properties ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Composition Range ◽  
The Other ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Structure Defects ◽  
X Ray ◽  
Dielectric Peak

Dielectric properties and the phase compositions of (1−x)Pb(Ni1/3Nb2/3)O3−xPbTiO3 ceramics were investigated. A morphotropic phase boundary (MPB) in the system between pseudocubic and tetragonal phase regions has been identified to lie in the composition range x = 0.34–0.38 by means of x-ray diffraction and dielectric measurements. The samples of composition lying near the MPB have good dielectric properties, but at the same time, exhibit two dielectric peaks. The possible reasons for the occurrence of dielectric bipeaks are discussed. One dielectric peak is phase transition peak, and the other peak lying in 130–150 °C temperature range is suggested to result from structure defects in the ceramics.

scholarly journals Study of structural and dielectric properties of Nickel-doped BaTiO3 material

2019 ◽  
Vol 8 (3) ◽  
pp. 228-233
Author(s):  
Hafes Ed-Dnoub ◽  
Ouafae El Ghadraoui ◽  
Mohammed Zouhairi ◽  
Ahmed Harrach ◽  
Tajeddine Lamcharfi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Scanning Electron Microscope ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Perovskite Type ◽  
Scanning Electron

In this work, the effect of nickel (Ni) insertion on the structural and dielectric properties of BaTiO3 material was investigated. A series of powders of composition Ba1-xNixTiO3 (x = 0, 0.05, 0.1, 0.15 and 0.20) were synthesized by solid method. The analysis by X-Ray Diffraction (XRD) shows that the obtained compounds crystallize in a phase of perovskite type. All the peaks are indexed in a phase of quadratic symmetry. Characterization by the Scanning Electron Microscope (SEM) indicates a heterogeneous microstructure of the grains. The study by spectroscopy of impedance in the frequency range [500Hz-1MHz] highlighted the effect of the nickel insertion on the transition temperature and the dielectric constant value.

Effect of (Ba1−xLax)TiO3 and (Pb1−xLax)TiO3 dopants in optical and dielectric properties of PMN-based transparent ceramics

2019 ◽  
Vol 33 (33) ◽  
pp. 1950408
Author(s):  
M. Ghasemifard ◽  
M. Ghamari ◽  
S. Samarin ◽  
J. F. Williams
Keyword(s):  
Dielectric Properties ◽  
Hot Pressing ◽  
Optical Transmittance ◽  
Transparent Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Combination Methods ◽  
Average Optical Transmittance

A relaxor electroceramic [Formula: see text]–[Formula: see text]–0.30-[Formula: see text] (PMN–PLT–BLT) with [Formula: see text] = 0.25, 0.50 and 0.75 was synthesized using the two combination methods of auto-combination and hot-pressing. Characterization of the crystal phase, microstructure, optical and dielectric properties of PMN–PLT–BLT was made primarily by X-ray diffraction and TEM and SEM methods. The pure perovskite crystals (rhombohedral and tetragonal) prepared at [Formula: see text] for 2 h calcination were revealed by using X-ray diffraction. The average optical transmittance of these electroceramics in the range between 450 nm and 900 nm is higher than 60% while in the IR region reached 100%. The PMN–PLT–BLT with [Formula: see text] = 0.75 displays the highest transparency around 70% near 1100 nm. The microstructures and dielectric measurements show that these three electroceramics have densities of about 98.8% and exhibit a normal relaxation characteristic.

scholarly journals Composition dependence of dielectric properties in Pb(Zn1∕3Nb2∕3)O3–PbTiO3–BaTiO3 (PZN–PT–BT) relaxor ferroelectric ceramics

2017 ◽  
Vol 07 (02) ◽  
pp. 1750008
Author(s):  
Qiang Gao ◽  
Li Jin ◽  
Yu Cui ◽  
Ye Zhao ◽  
Kun Yu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Composition Dependence ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cation Disorder ◽  
Diffusion Phase ◽  
A Site

Perovskite solid solution ceramics of PZN–PT–BT with several compositions were synthesized by solid-state reaction method. X-ray diffraction results indicate pure perovskite structures for all samples. Dielectric measurements show that the implicit Ba(Zn[Formula: see text]Nb[Formula: see text])O3(BZN) composition could broaden the diffusion phase transition (DPT) peaks and lower the [Formula: see text] and [Formula: see text] values. The observed dielectric properties may be caused by the increased cation disorder due to the substitution of barium onto the A-site and titanium onto the B-site.

scholarly journals Study of structural and dielectric properties of Nickel-doped BaTiO3 material

2019 ◽  
Vol 8 (3) ◽  
pp. 228
Author(s):  
Hafes Ed-Dnoub ◽  
Ouafae El Ghadraoui ◽  
Mohammed Zouhairi ◽  
Ahmed Harrach ◽  
Tajeddine Lamcharfi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Scanning Electron Microscope ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Perovskite Type ◽  
Scanning Electron

<p><span lang="EN-US">In this work, the effect of nickel (Ni) insertion on the structural and dielectric properties of BaTiO<sub>3</sub> material was investigated. A series of powders of composition <span>Ba<sub>1-x</sub>Ni<sub>x</sub>TiO<sub>3</sub> </span>(x = 0, 0.05, 0.1, 0.15 and 0.20) were synthesized by solid method. The analysis by X-Ray Diffraction (XRD) shows that the obtained compounds crystallize in a phase of perovskite type. All the peaks are indexed in a phase of quadratic symmetry. Characterization by the Scanning Electron Microscope (SEM) indicates a heterogeneous microstructure of the grains. <span>The study by spectroscopy of impedance in</span> the frequency range [500Hz-1MHz] <span>highlighted the effect of the nickel insertion on </span>the transition temperature and the dielectric constant value.</span></p>

scholarly journals Effect of Cu Doping on Structural and Dielectric Properties of Pb1-xCux(Zr0.52Ti0.48)O3(PCxZT) (0 ≤ x ≤ 0.2) Ceramics Prepared by Sol-Gel Method

2021 ◽  
Vol 33 (3) ◽  
pp. 665-670
Author(s):  
M. Ahabboud ◽  
T. Lamcharfi ◽  
F. Abdi ◽  
N. Hadi ◽  
F.Z. Ajyaje ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Cu Doping ◽  
X Ray ◽  
Different Temperatures

In present work, the structural and dielectric properties of Pb1-xCuxZr0.52Ti0.48O3 (PCxZT) ceramics where x = 0. 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20 were studied. Powder of the compositions (PCxZT) was obtained by sol-gel route, the powders were calcined at 700 ºC for 4 h and sintered at 1100 ºC for 4 h. X-ray diffraction analysis and Raman spectroscopy suggest the formation of mixed-phase of tetragonal and rhombohedral structure which was confirmed by Rietveld refinement. Dielectric measurements of the compounds were studied as a function of temperature (from room temperature to 420 ºC at different frequencies) and as a function of frequency (from 100 Hz to 2 MHz at different temperatures). The temperature variation of the real permittivity gives evidence of the ferroelectric phase transition as well as of the resonance behaviour also observed in the dielectric permittivity frequency-dependent variation.

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