High-Performance Lead-Free Barium Titanate Piezoelectric Ceramics

2008 ◽  
Vol 54 ◽  
pp. 7-12 ◽  
Author(s):  
Tomoaki Karaki ◽  
Masatoshi Adachi ◽  
Kang Yan
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Barium Titanate ◽  
Phase Transition Temperature ◽  
Room Temperature ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Piezoelectric Constants

Barium titanate (BaTiO3) ceramics with a high-density were fabricated by two-step sintering method from hydrothermally synthesized 100 nm BaTiO3 nano-particles. The best specimen with an average grain size of 1.6 μm and a density of 5.91 g/cm3 (98.3% of the theoretical value). The dielectric constant was 4500 and electromechanical coupling factor kp was 45%. Large piezoelectric constants d33 = 460 pC/N and d31 = -185 pC/N were observed in the specimens. This was an important practical result towards obtaining a high d33 in non-lead-based BaTiO3 ceramics manufactured by a low-cost process. These results also indicated the possibility of using BaTiO3 ceramics in piezoelectric devices at room temperature. Temperature dependence of dielectric constant showed two peaks located at 24 and 126 oC, corresponding to orthorhombic-to-tetragonal phase transition temperature Tot and Curie temperature Tc, respectively. Owing to the size effect of nanocrystals, Tot shifted to 24 oC. The maximum of electromechanical coupling factor kp appeared close to the phase transition temperature. It also caused a very large temperature coefficient of resonance frequency from room temperature to 60 oC. Hysteresis curve measurement showed a very low coercive field Ec = 115 V/mm. A large Poisson’s ratio, about 0.38, was determined from the ratio of overtone frequency and resonant frequency in the planar mode. The high Poisson’s ratio and the large dielectric constants are most likely the origin of the high piezoelectric constants in the ceramics.

scholarly journals Piezoelectric and pyroelectric properties of Mn-doped 0.36Pb(In1/2Nb1/2)O3-0.36Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 ceramics

2020 ◽  
Author(s):  
Xiaoli Huang ◽  
Yanxue Tang ◽  
Feifei Wang ◽  
Xiangyong Zhao ◽  
Zhihua Duan ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Pyroelectric Coefficient ◽  
Cubic Phase ◽  
Pyroelectric Properties ◽  
Mn Doped

Abstract Piezoelectric and pyroelectric properties as well as strain behavior of 0.5 mol% Mn-doped 0.36Pb(In1/2Nb1/2)O3-0.36Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (Mn-PIMNT) ceramics were studied. High piezoelectric coefficient of d33 = 235 pC/N, planar electromechanical coupling factor of kp = 43.1% and the high-power Figure of Merit (FOM = 60160 pC/N) were achieved in Mn-PIMNT ceramics. Furthermore, the ceramics exhibited high pyroelectric coefficient of p = 4.8×10-4 Cm-2K-1, figures of merit for the current responsivity of Fi = 1.92×10-10 mV-1, the voltage responsivity of Fv = 0.028 m2C-1, and the detectivity of Fd = 2.317×10-5 Pa-1/2 at room temperature. The excellent piezoelectric and pyroelectric properties together with high ferroelectric rhombohedral to tetragonal phase transition temperature of Trt = 146 ℃ and ferroelectric tetragonal to cubic phase transition temperature of TC = 188 ℃ make the Mn-PIMNT ceramics suitable for high-temperature piezoelectric and pyroelectric devices.

Piezoelectric Properties and Depolarization Temperature of NaNbO3-LiNbO3 Lead-Free Piezoelectric Ceramics

2008 ◽  
Vol 388 ◽  
pp. 233-236 ◽  
Author(s):  
Rintaro Aoyagi ◽  
Makoto Iwata ◽  
Masaki Maeda
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Electromechanical Coupling ◽  
Thermal Hysteresis ◽  
Longitudinal Mode ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Depolarization Temperature ◽  
Higher Temperature ◽  
Curie Temperature Tc

Piezoelectric and dielectric properties of (LixNa1-x)NbO3 (LNN100x; x≤0.14) ceramics were investigated according to phase transition The highest electromechanical coupling factor, kp, of 0.247 was obtained for LNN12 which has a composition with a morphotropic phase boundary at room temperature. On the other hand, the coupling factor of k33 with longitudinal mode was almost constant for all compositions of x. The dielectric constant, ε r, before poling treatment exhibited a thermal hysteresis near the Curie temperature, TC, for all compositions. The depolarization temperature of LNN6 was higher than the TC before poling treatment. In addition, the peak of free permittivity, ε33 T, was shifted to higher temperature. It was considered that the phase transition was induced by the electric field during poling treatment.

Change of Phase Transition Temperature in Band Engineered Ferroelectric Lanthanum-Modified Bismuth Titanates

2020 ◽  
Vol 20 (11) ◽  
pp. 7135-7139
Author(s):  
Rui Tang ◽  
Sangmo Kim ◽  
Chung Wung Bark
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Ferroelectric Properties ◽  
Solar Spectrum ◽  
Ferroelectric Material ◽  
Transition Temperatures ◽  
Phase Transition Temperatures ◽  
Increasing Temperature

The ferroelectric material chosen for a solar cell has to absorb as much of the solar spectrum as possible, therefore a low band gap is desirable, but it is rarely known for phase transition temperature on the bandgap engineered ferroelectric materials. The phase transition temperature of a ferroelectric material can be determined by monitoring its dielectric constant with increasing temperature, as the dielectric constant changes abruptly at the phase transition temperature. Here, we inform the measurement of the phase transition temperature of the ferroelectric complex oxide Bi3.25La0.75Ti3O12 as well as cobalt and iron doped Bi3.25La0.75Ti3O12 bulk ceramics for photovoltaic cells based on dielectric monitoring with changing temperature. We synthesized lanthanum-modified bismuth-titanate-based ceramics with various doping concentrations transition metal to Ti. X-ray diffraction analysis revealed that all the compounds crystallized in an orthorhombic structure. Their morphologies and size distributions were observed using scanning electron microscopy. From the ultraviolet-visible spectroscopy absorption spectra of the synthesized powder, bandgaps were checked. An inductance-capacitance-resistance meter was used to obtain the relationship between dielectric responses and the temperature of the targets in a tube furnace. We observed that the dielectric constant increases gradually with increasing temperature, until the transition temperature and subsequently decreases, and we were able to determine the phase transition temperatures of the tested materials. Furthermore, the results revealed that all the doped bismuth titanates keep their phase transition temperatures, which were sufficiently high, to maintain their ferroelectric properties above room temperature.

Improved Curie Temperature of Li-Doped Lead-Free (K,Na)NbO3 Ceramics Analysis

2014 ◽  
Vol 1061-1062 ◽  
pp. 91-95
Author(s):  
Rui Zhu Zhang ◽  
Wen Peng Guo ◽  
Gao Lei Zhao
Keyword(s):  
Phase Transition ◽  
Curie Temperature ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Tetragonal Symmetry ◽  
Negative Effects ◽  
Li Content

(K,Na)NbO3(KNN)-based lead-free piezoelectric ceramic could be fabricated by ordinary solid sintering method.This paper reported preferable properties of solid solutions (1-x)(Na0.535K0.480)NbO3-xLiNbO3(x=0.050,0.055,0.060,0.065 and 0.070 successively) all sintered at 1060°C.The nonconservation of charge suppressed negative effects caused by evaporations of K&Na and doped Li occupied A sites in ABO3perovskite structure lattices led to the intensification of lattice distortion.XRD result showd phase transition from coexistence of orthorhombic and tetragonal symmetry to tetragonal.Polymorphic phase boundary could be observed when 0.050≤ x≤ 0.060.Coexistence of orthorhombic and tetragonal phases brought improvements of piezoelectric coefficient d33and electromechanical coupling factor kp,whose top values were 162 pC/N and 28.1% in this paper. Positive correlation between the Curie temperature and Li content proved that a distorted crystal lattice needed more energy to accomplish its phase transition from tetragonal to cubic than a normal one.

Influence of Poling Conditions on the Characteristics of PZT Ceramics

2011 ◽  
Vol 284-286 ◽  
pp. 1375-1380 ◽  
Author(s):  
Ming Cheng Chure ◽  
Ping Cheng Chen ◽  
Long Wu ◽  
Bing Huei Chen ◽  
King Kung Wu
Keyword(s):  
Dielectric Constant ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Poling Field ◽  
Pzt Ceramics ◽  
Poling Process ◽  
Poling Temperature ◽  
Higher Temperature ◽  
Planar Electromechanical Coupling Factor

In the poling process of PZT ceramics, the poling temperature is a critical condition. When the poling temperature is too low, no matter how high is the poling field and how long is the poling time, the planar electromechanical coupling factor kpis lower. When the poling temperature is higher enough, the kpcan reach to a saturated value with a lower poling field and short poling time. The variation of dielectric constant with the poling conditions is the same as that of planar electromechanical coupling factor. When poling with a low temperature, the dielectric constant after poling is lower than 1400. When poling with higher temperature, no matter how high is the poling field and how long is the poling time, the dielectric constant after poling is higher than 1500.

The Effects of Ba(Zr0.05Ti0.95)O3 Addition on Piezoelectric Properties and Microstructures of (Na0.5Bi0.5)0.94Ba0.06TiO3 Ceramics

2017 ◽  
Vol 732 ◽  
pp. 69-75
Author(s):  
Tai Kuang Lee ◽  
Jyun Hung Chen ◽  
Ying Chieh Lee
Keyword(s):  
Phase Transition ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Doping Content ◽  
Remarkable Effect ◽  
Significant Change

(Na0.5Bi0.5)0.94Ba0.06TiO3 (NBBT) ceramics doped with 0.1∼2.0 mol.% Ba (Zr0.05Ti0.95)O3 were investigated in terms of the sintering, microstructure, phase transition, and piezoelectric properties. BZT doping has no remarkable effect on the microstructure and densification within the studied doping content. Up to 2 mol.% BZT can dissolve into the lattice of NBBT ceramics, and the structure symmetry is not changed. However, a significant change in the piezoelectric properties took place. The piezoelectric coefficient d33 for the 0.1 wt.% BZT-doped NBBT ceramics sintered at 1150 °C was found to be 120 pC/N and the electromechanical coupling factor kp = 0.24.

Piezoelectric and Ultrasonic Studies of Mixed AgxCu1-xInP2(S,Se)6 Layered Crystals

2010 ◽  
Vol 636-637 ◽  
pp. 398-403 ◽  
Author(s):  
Vytautas Samulionis ◽  
Juras Banys ◽  
Yulian Vysochanskii
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Electromechanical Coupling ◽  
Medical Diagnostics ◽  
Opposite Polarity ◽  
Ultrasonic Waves ◽  
Coupling Constants ◽  
Piezoelectric Response ◽  
Layered Crystals

The paper reviews recent results of ultrasonic and piezoelectric investigation in CuInP2S6 family ferroelectric layered crystals and their solid solutions in the temperature range 100-360 K. It was shown that, Cu substitution by Ag lowers the phase transition temperature. In investigated AgxCu1-xInP2(S,Se)6 crystals above the phase transition (PT) temperature the piezoelectric response was absent and appeared only below the transition. At low temperatures T < 220 K the layered AgxCu1-xInP2Se6 crystals are ferroelectric. Piezoelectric sensitivity in the ferroelectric phase increases with DC field applied along the c-axis, then saturates, and after reversion of voltage the piezoelectric signal decreases, at field near coercive changes sign, and saturates again at high voltage of opposite polarity In the paraelectric phase under external DC electric field, applied along c-axis normal to layers, thin AgxCu1-xInP2Se6 plates can effectively excite and detect ultrasonic waves, due to electrostriction. The same behaviour was observed and in AgxCu1-xInP2S6 crystals. The critical ultrasonic velocity anomalies were observed in the vicinity of PT. In CuInP2S6 crystals with addition of In i.e. indium rich materials the phase transition temperature could be raised to T > 330 K what is important for applications in medical diagnostics ultrasonic transducers. In all these materials the poling conditions were investigated and it was shown that after long time exposing in DC field the piezoelectric sensitivity sufficiently increases and electromechanical coupling constants as high as > 50 % could be obtained.

The Effect of the Lipid Bilayer State on Fluorescence Intensity of Fluorescein-PE in a Saturated Lipid Bilayer

2000 ◽  
Vol 55 (5-6) ◽  
pp. 418-424 ◽  
Author(s):  
Marek Langner ◽  
Hanna Pruchnik ◽  
Krystian Kubica
Keyword(s):  
Phase Transition ◽  
Dielectric Constant ◽  
Transition Temperature ◽  
Lipid Bilayer ◽  
Phase Transition Temperature ◽  
Conformational Changes ◽  
Fluorescence Intensity ◽  
Electrostatic Potential ◽  
Salt Concentration ◽  
Membrane Interface

Fluorescein-PE is a fluorescence probe that is used as a membrane label or a sensor of surface associated processes. Fluorescein-PE fluorescence intensity depends not only on bulk pH, but also on the local electrostatic potential, which affects the local membrane interface proton concentration. The pH sensitivity and hydrophilic character of the fluorescein moiety was used to detect conformational changes at the lipid bilayer surface. When located in the dipalmitoylphosphatidylcholine (DPPC) bilayer, probe fluorescence depends on conformational changes that occur during phase transitions. Relative fluorescence intensity changes more at pretransition than at the main phase transition temperature, indicating that interface conformation affects the condition in the vicinity of the membrane. Local electrostatic potential depends on surface charge density, the local dielectric constant, salt concentration and water organisation. Initial increase in fluorescence intensity at temperatures preceding that of pretransition can be explained by the decreased value of the dielectric constant in the lipid polar headgroups region related in turn to decreased water organisation within the membrane interface. The abrupt decrease in fluorescence intensity at temperatures between 25 °C and 35 °C (DPPC pretransition) is likely to be caused by an increased value of the electrostatic potential, induced by an elevated value of the dielectric constant within the phosphate group region. Further increase in the fluorescence intensity at temperatures above that of the gel-liquid phase transition correlates with the calculated decreased surface electrostatic potential. Above the main phase transition temperature, fluorescence intensity increase at a salt concentration of 140 m M is larger than with 14 m M . This results from a sharp decline of the electrostatic potential induced by the phosphocholine dipole as a function of distance from the membrane surface.

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