Large electrostrictive effect in Sn-doped NBT–BT lead-free relaxor ceramics

2020 ◽  
Vol 34 (11) ◽  
pp. 2050100
Author(s):  
W. P. Cao ◽  
J. Sheng ◽  
Z. Liu ◽  
C. Gao ◽  
Z. H. Wang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Room Temperature ◽  
Relaxor Ferroelectrics ◽  
Lead Free ◽  
Ferroelectric Relaxor ◽  
Pseudocubic Phase ◽  
Further Development ◽  
Electrostrictive Effect

In this work, we design and adjust the composition in [Formula: see text]–[Formula: see text] lead-free relaxor ferroelectrics by doping SnO2 to introduce a relaxor phase and accordingly obtain prominent lead-free electrostrictors. It was found that all the samples exhibited ideal features of relaxor ferroelectrics and the ferroelectric-relaxor phase transition temperature of the ceramics was adjusted to near or below room temperature after doping with a handful of [Formula: see text]. A relatively high electrostrictive coefficient [Formula: see text] of 0.0293 m4/C2 was achieved for the composition with [Formula: see text], which was attributed to the formation of relaxor pseudocubic phase developed by the [Formula: see text] substitution. These results provide some instructive thoughts for the further development of [Formula: see text]-based electrostrictive materials by B-site doping.

Temperature dependence of piezoelectric properties of 0.67 Pb(Mg1/3Nb2/3)O3–0.33 PbTiO3 single crystals

2003 ◽  
Vol 18 (2) ◽  
pp. 537-541 ◽  
Author(s):  
Ping-chu Wang ◽  
Xiao-ming Pan ◽  
Dong-lin Li ◽  
Yuan-wei Song ◽  
Hao-su Luo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Phase Transition Temperature ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Device Design ◽  
Temperature Range ◽  
Approach Zero

Piezoelectric properties k33 and d33 of 0.67 Pb(Mg1/3Nb2/3)O3–0.33 PbTiO3 single crystals grown by a modified Bridgman method were measured in the temperature range of 20–150 °C. Recoverability of the properties after the samples were heated to 110 °C, above the ferroelectric–ferroelectric (F–F) phase transition temperature of the composition, was found. From 20 to approximately 80 °C, k33 increases slightly, while d33 is almost doubled. Between approximately 90 and 100 °C, k33 decreases sharply to roughly a level of PZT-5 ceramics and d33 decreases to about 700 pC/N. They increase again with further increase of temperature; at 140 °C they attain 0.74 and approximately 1300 pC/N, respectively, and then decrease quickly and approach zero at about 150 °C. When heating to 110 °C followed by cooling to room temperature, the property decay is small. After more than one dozen heating–cooling cycles, k33 and d33 tend to be stable at 0.89 and approximately 1220 pC/N, respectively. The results might be helpful for device design and applications of PMN–PT single crystals.

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 Martensite Transformation and Mechanical Properties of Polycrystalline Co-Ni-Al Alloys with Gd Doping

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 848 ◽  
Author(s):  
Jia Ju ◽  
Huan Liu ◽  
Liguo Shuai ◽  
Zhuang Liu ◽  
Yan Kang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Compressive Strength ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Martensite Transformation ◽  
Room Temperature ◽  
Al Alloys ◽  
Β Phase

In order to improve the mechanical properties and phase transition temperature, the influence of Gd doping on the microstructure, phase transition temperature and mechanical properties of Co35Ni32Al33 alloy was investigated. The results show that the γ+β phase was observed in the microstructure of the sample with less Gd doping and the γ phase+martensite was found with more Gd content. The phase transition temperature apparently increases with Gd doping and the phase transition temperature goes over room temperature when the Gd is 3 at.% or more. With increasing Gd doping, more γ phase appears in the sample which results in decrease in hardness. The compressive strength decreases from 2274 to 1630 MPa and the ductility increase from 4.2 to 12.9% with increasing Gd content.

Dielectric, Piezoelectric, Pyroelectric Properties and Polymorphic Phase Transition of 0.95 (KXNa1-X) NbO3-0.05LiSbO3 Lead-Free Ferroelectric Ceramics

2013 ◽  
Vol 377 ◽  
pp. 161-165
Author(s):  
Yang Yang Zhang ◽  
Jin Ping Zhang ◽  
Er Ping Wang ◽  
Sheng Lin Jiang ◽  
Lin Lu
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Electrical Properties ◽  
Room Temperature ◽  
Lead Free ◽  
Ferroelectric Ceramics ◽  
Polymorphic Phase Transition ◽  
Lead Free Ceramics ◽  
Enhanced Properties ◽  
Tetragonal Phase Transition

0.95 (KXNa1-X) NbO3-0.05 LiSbO3(KNN-LS-X) (X=0.4-0.5) lead-free ceramics were prepared by conventional solid method. The effect of K/Na ratio on the dielectric, piezoelectric, pyroelectric and polymorphic phase transition was studied. The results show that the electrical properties strongly depend on the K/Na ratio. The KNN-LS-X(X=0.45) ceramics exhibit enhanced properties (εr=891.267,d33=222pC/N,Kp=0.43517,Qm=64.72,p=15×10-4C/m2K). Enhanced electrical properties of the KNN-LS-X (X=0.45) ceramics could be attributed to the effect of K/Na ratio modifying the polymorphic orthorhombic-tetragonal phase transition temperature to room temperature, which could make KNN-LS-X (X=0.45) ceramics use as a new ferroelectric sensor.

Phase transition metal–crown ether coordination compounds tuned by metal ions

2016 ◽  
Vol 45 (3) ◽  
pp. 1000-1006 ◽  
Author(s):  
Qiong Ye ◽  
Hui-Ting Wang ◽  
Lin Zhou ◽  
Li-Hui Kong ◽  
Heng-Yun Ye ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Transition Metal ◽  
Crown Ether ◽  
Metal Ions ◽  
Phase Transition Temperature ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Metal Center

(15-Crown-5)(BiCl3) and (15-crown-5)(SbCl3) are discovered to show phase transitions above room temperature, where the phase transition temperature relates to the metal center.

Low temperature crystal structure of TbAsO4 and DyAsO4

1977 ◽  
Vol 55 (18) ◽  
pp. 1633-1640 ◽  
Author(s):  
F. G. Long ◽  
C. V. Stager
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Low Temperature ◽  
Phase Transition Temperature ◽  
Room Temperature ◽  
X Rays ◽  
Single Crystal Diffraction ◽  
Low Temperature Crystal Structure ◽  
Jahn Teller ◽  
Good Agreement

The crystal structures of TbAsO4 and DyAsO4 have been determined by X rays, using single crystal diffraction techniques. The structures have been determined both above and below the co-operative Jahn–Teller phase transition temperature. The structures at room temperature are in good agreement with previous results. The low temperature structures, below the phase transition temperature, are compared to the theory of Elliott, Harley, Hayes, and Smith.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

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