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.

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 Dielectric Properties of Bi2O3-Doped (Bi0.5Na0.5)0.94Ba0.06TiO3 Lead-Free Piezoelectric Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1915-1918 ◽  
Author(s):  
Jian Qiang Hu ◽  
Zhi Wu Chen
Keyword(s):  
Dielectric Properties ◽  
Electromechanical Coupling ◽  
Relative Dielectric Constant ◽  
Piezoelectric Ceramics ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
Conventional Sintering

Bi2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT6) lead-free piezoelectric ceramics were fabricated by a conventional sintering technique. The effects of Bi2O3 on the piezoelectric properties and microstructures of the doped BNBT6 were investigated. X-ray diffraction analysis showed that a solid solution was formed when Bi2O3 diffused into BNBT6 lattice and the crystal structure of the sintered hybrid changed from rhombohedral to tetragonal symmetry with increasing Bi2O3 amount. Piezoelectric and dielectric properties measurements revealed that doping Bi2O3 within a certain range enhanced the piezoelectric coefficient (d33), electromechanical coupling factor (kp), relative dielectric constant (ε33 T/ε0), and dielectric loss (tanδ). When 3mol% Bi2O3 was doped, both d33 and kp of the ceramics reached their maxima, 165pC/N and 24%, respectively.

Effects of AgSbO3 on the Piezoelectric/Dielectric Properties and Phase Transition of Li2O Doped NKN Lead-Free Piezoelectric Ceramics

2011 ◽  
Vol 287-290 ◽  
pp. 801-804 ◽  
Author(s):  
Man Soon Yoon ◽  
Neamul Hayet Khansur ◽  
Woong Jae Lee ◽  
Young Geun Lee ◽  
Soon Chul Ur
Keyword(s):  
Phase Transition ◽  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Relative Dielectric Permittivity ◽  
Planar Electromechanical Coupling Factor

The effect of AgSbO3on the piezoelectric properties of (K0.5Na0.5)0.95Li0.05NbO3was examined. The AgSbO3doped KNLN samples sintered at 1050°C showed the maximum values of the sintering density of 4.56 g/cm3compared to un-doped KNLN samples sintered at same temperature with 4.25 g/cm3. Moreover, the addition of AgSbO3enhanced the piezoelectric and dielectric properties. Piezoelectric constant (d33), the planar electromechanical coupling factor (kp) and the relative dielectric permittivity (K33T) increased up to 230pC/N, 43.5%, 1080, respectively, with addition of AgSbO3.

Lead-Free BSZT/Epoxy 1-3 Composites for Ultrasonic Transducer Applications

2011 ◽  
Vol 254 ◽  
pp. 90-93 ◽  
Author(s):  
Siu To Felix Lee ◽  
Kwok Ho Lam ◽  
Xu Ming Zhang ◽  
Helen L. W. Chan
Keyword(s):  
Biomedical Applications ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Ultrasonic Transducer ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Electromechanical Properties ◽  
Large Bandwidth ◽  
Barium Strontium

With high piezoelectric coefficient (d33> 300 pC/N) and electromechanical coupling factor (kt = 0.45), lead-free barium strontium zirconium titanate ((Ba0.95Sr0.05) (Zr0.05Ti0.95) O3, abbreviated as BSZT)was used to fabricate BSZT/epoxy 1-3 composites with different volume fractions of BSZT ranging from 0.55 - 0.85. The electromechanical properties of the 1-3 composites were determined by the resonance technique. It was found that the theoretical modeling of the 1-3 composites matches quite well with the measured material properties.The 1-3 composite with f = 0.65 was chosen to be fabricated as a transducer due to its comparatively high value of kt. The BSZT/epoxy 1-3 composite transducer demonstrates large bandwidth with good sensitivity, suggesting high potential in biomedical applications.

Piezoelectric and Dielectric Properties of (Bi0.5Na0.5)0.94(Ba1-xSrx)0.06TiO3 Lead-Free Piezoelectric Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1911-1914 ◽  
Author(s):  
Zhi Wu Chen ◽  
Zhen Ya Lu ◽  
Jian Qiang Hu
Keyword(s):  
Crystal Structure ◽  
Electromechanical Coupling ◽  
Relative Dielectric Constant ◽  
Piezoelectric Ceramics ◽  
Electromechanical Coupling Factor ◽  
Xrd Analysis ◽  
Coupling Factor ◽  
Lead Free ◽  
Tetragonal Symmetry ◽  
Pure Perovskite Structure

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.94(Ba1-xSrx)0.06TiO3 (abbreviated as BNBST-100x, with x ranges from 0.02 to 0.1) have been investigated. Effects of amount of Sr-substitution on the electrical properties and crystal structure of the ceramics were studied. The BNBST-100x ceramics sintered at 1200°C for 2h in air have high density around 5.69~5.75g/cm3. X-ray diffraction (XRD) analysis shows that all of the BNBST-100x ceramics have pure perovskite structure. At high amount level of Sr-substitution, the crystal structure of the samples changes from rhombohedral to tetragonal symmetry. Piezoelectric and dielectric measurements reveal that Sr-substitution amount within a certain range will lead to the increase of piezoelectric coefficient (d33), electromechanical coupling factor (kp), and relative dielectric constant (ε33 T/ε0). At 6 mol% Sr-substitution level, the d33 and kp of the ceramics reach maximum, with values of 168 pC/N and 34%, respectively.

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.

(1-x)(K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xBiFeO3 Lead-Free Piezoelectric Ceramics with CuO Sintering Aid

2011 ◽  
Vol 687 ◽  
pp. 228-232
Author(s):  
Yong Jie Zhao ◽  
Yu Zhen Zhao ◽  
Rong Xia Huang ◽  
Rong Zheng Liu ◽  
He Ping Zhou
Keyword(s):  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Piezoelectric Ceramics ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Mechanical Quality Factor ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Diffraction Patterns

(1-x) (K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xmolBiFeO3 (x=0, 0.002, 0.004, 0.006, 0.008) doped with 0.8mol%CuO lead-free piezoelectric ceramics were prepared by the solid state reaction technique. X-ray diffraction patterns suggested that all the ceramics presented perovskite structure. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. The ceramic (x=0.002) near room temperature exhibited excellent electrical properties (piezoelectric constant d33=172pC/N, planar electromechanical coupling factor kp=0.43, and dielectric constant =418). A relatively high mechanical quality factor (Qm=200) was also obtained in this particular composition. All these results revealed that this system might become a promising candidate for lead-free piezoelectric materials.

Investigation on Electrical Properties of CaCu3Ti4O12-Modified (Na,Bi)TiO3-BaTiO3 Lead Free Piezoceramics

2014 ◽  
Vol 887-888 ◽  
pp. 289-293
Author(s):  
Jing Chang Zhao ◽  
Zhen Lai Zhou
Keyword(s):  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Piezoelectric Ceramics ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Mechanical Quality Factor ◽  
Lead Free ◽  
Lead Free Ceramics ◽  
Structure Morphology

(Na,Bi)TiO3-BaTiO3lead free piezoelectric ceramics were fabricated with modification of CaCu3Ti4O12additives. The phase structure, morphology, dielectric and piezoelectric properties of prepared samples were investigated, respectively. It was found that CaCu3Ti4O12additives evidently improve the polarization properties of (Na,Bi)TiO3-BaTiO3lead free ceramics and the obtained samples exhibit an excellent piezoelectric properties (electromechanical coupling factorKp=31%, mechanical quality factorQm=151 and piezoelectric constantd33=160pC/N). According to results, the effect of CaCu3Ti4O12additives on electrical properties of (Na,Bi)TiO3-BaTiO3lead free piezoelectric ceramics is discussed.

Effect of DC Poling Field on Domain Behavior in Lead-Free Piezoelectric Ceramics

2010 ◽  
Vol 67 ◽  
pp. 34-41
Author(s):  
Toshio Ogawa ◽  
Masahito Furukawa ◽  
Takeo Tsukada
Keyword(s):  
Electromechanical Coupling ◽  
Bismuth Titanate ◽  
Domain Switching ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Poling Field ◽  
Lead Free Ceramics ◽  
Titanate Ceramics ◽  
Dielectric And Piezoelectric Properties

Poling characteristics, especially DC poling field (E) dependence of dielectric and piezoelectric properties were investigated to evaluate the domain behavior in lead-free ceramics such as alkali niobate and alkali bismuth titanate ceramics. The domain switching was confirmed by the E to realize minimum dielectric constant (εr), minimum electromechanical coupling factor (k) and maximum frequency constant (fc), because of domain clamping. On the other hand, the domain rotation occurred at the E to obtain maximum εr and minimum fc. These phenomena are observed in the lead-free ceramics as well as PZT ceramics.

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