scholarly journals Ultrahigh Electromechanical Coupling and Its Thermal Stability in (Na1/2Bi1/2)TiO3-Based Lead-Free Single Crystals

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 435
Author(s):  
Chao Chen ◽  
Li Yang ◽  
Xingan Jiang ◽  
Xiaokun Huang ◽  
Xiaoyi Gao ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Lead Free ◽  
Electromechanical Coupling Coefficient ◽  
Force Microscopy ◽  
Scattering Spectra ◽  
Raman Scattering Spectra ◽  
Piezoelectric Force Microscopy ◽  
Microscopy Characterization ◽  
Thickness Mode

In this work, we report the ultrahigh electromechanical coupling performance of NBT-6BT-KNN lead-free single crystal at room temperature. The thickness mode electromechanical coupling coefficient (kt) and the 31 mode electromechanical coupling coefficient (k31) reach 69.0% and 45.7%, respectively, which are superior to the PZT-5H lead-based ceramics of kt~60% and k31~39%. In addition, the evolution of the crystal structure and domain morphology is revealed by Raman scattering spectra, a polarizing microscope and piezoelectric force microscopy characterization.

Effect of Bi2O3 Addition on the Electrical and Physical Properties of Lead-Free 0.98(Na0.5K0.5)NbO3-0.02 Ba(Zr0.04Ti0.96)O3 Piezoelectric Ceramics

2010 ◽  
Vol 434-435 ◽  
pp. 413-416 ◽  
Author(s):  
Chun Huy Wang
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Orthorhombic Phase ◽  
Lead Free ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
Sintering Aid ◽  
X Ray ◽  
Thickness Mode ◽  
Planar Mode

The 0.98(Na0.5K0.5)NbO3–0.02Ba(Zr0.04Ti0.96)O3 ceramics have been prepared following the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Zr0.04Ti0.96)O3 diffuses into the lattice of (Na0.5K0.5)NbO3 to form a solid solution, in which a orthorhombic phase with a perovskite structure was found In order to improve the sinterability of the ceramics, Bi2O3 additions were used as a sintering aid. The electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.3 and 0.55, respectively, at the sintering of 1100oC for 5 h. For 0.98NKN-0.02BZT ceramics by doping 0.5 wt.% Bi2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.21 and 0.57, respectively. The ratio of thickness coupling coefficient to planar coupling coefficient is 2.7.

Piezoelectric and Strain Properties of Strontium-Doped BZT-BCT Lead-Free Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1385-1389 ◽  
Author(s):  
Wang Feng Bai ◽  
Wei Li ◽  
Bo Shen ◽  
Ji Wei Zhai
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Electromechanical Coupling Coefficient ◽  
Lead Free Ceramics ◽  
Pure Perovskite Phase ◽  
Free Material

Lead-free piezoelectric ceramics, (Ba0.85-xSrxCa0.15)(Zr0.1Ti0.9)O3 (BSCZT, x=0.01-0.07), were prepared via a solid-state reaction route. The dielectric properties, ferroelectric properties, piezoelectric and strain properties of BSCZT ceramics were studied. The phase structure and microstructure were investigated by X-ray diffraction and scanning electron microscope, respectively. Results showed that dense ceramics with pure perovskite phase were obtained. At room temperature, the samples with x=0.03 exhibited excellent properties with large piezoelectric coefficient d33=534pC/N, planar mode electromechanical coupling coefficient kp=47.7%, thickness mode electromechanical coupling coefficient kt= 42% and high strain levels of 0.34%. In addition, the study of electrical properties suggested that the Curie temperature decreased linearly from 92oc to 73oc with the increasing doping content of strontium in BCZT ceramics. The remnant polarizations, piezoelectric coefficient and strain levels were all increased as the Sr content increased and then decreased with further increased Sr doping level, giving the maximum values at the Sr content of 3mol%. These results indicated that the BSCZT system is a promising lead-free material for applications in the future.

Effect of Bi2O3 Addition on the Physical and Electrical Properties of Lead-Free (Na0.5Bi0.5)TiO3-Ba(Sn0.08Ti0.92)O3 Ceramics

2011 ◽  
Vol 415-417 ◽  
pp. 1051-1054
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Coupling Coefficient ◽  
High Frequency ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
Coupling Coefficients ◽  
Lead Free Ceramics ◽  
Thickness Mode ◽  
Planar Mode

In the present study, various quantities of Bi2O3were added into 0.98(Na0.5Bi0.5)TiO3-0.02Ba(Sn0.08Ti0.92)O3(0.98NBT-0.02BST) ceramics. High-density samples were obtained through the addition of Bi2O3into 0.98NBT-0.02BST ceramic. It was found that 0.98NBT-0.02BST with the addition of 0~3.0 wt.% Bi2O3exhibit relatively good piezoelectric properties. For 0.98NBT-0.02BST ceramic with the addition of 2 wt.% Bi2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.12 and 0.61, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 5.1. It is obvious that 0.98NBT-0.02BST solid solution ceramic by adding low quantities of Bi2O3is one of the promising lead-free ceramics for high frequency electromechanical transducer applications.

The Investigation of Preferred Orientation Growth of ZnO Films on the Ceramic Substrates

2003 ◽  
Vol 764 ◽  
Author(s):  
Sheng-Yuan Chu ◽  
Te-Yi Chen ◽  
Walter Water ◽  
Tung-Yi Huang
Keyword(s):  
Coupling Coefficient ◽  
Gas Flow ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Coefficient ◽  
Zno Films ◽  
Ceramic Substrates ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gas Flow Ratio ◽  
Temperature Coefficient Of Frequency

AbstractPoly-crystal ZnO films with c-axis (002) orientation have been successfully grown on the lead-based ceramic substrates by r.f. magnetron sputtering technique. The deposited films were characterized as a function of deposition time and argon-oxygen gas flow ratio. Crystalline structures of the films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Highly oriented films with c-axis normal to the substrates can be obtained by depositing under a total pressure of 10mTorr containing 50% argon and 50% oxygen and r.f. power of 70W for 3 hours. The phase velocity, electromechanical coupling coefficient and temperature coefficient of frequency of SAW device with ZnO/IDT/PT-ceramic structure were investigated. It shows that the preferred oriented ZnO film is beneficial for improving the electromechanical coupling coefficient of SAW device.

Physical and Electrical Properties of Lead-Free (Na0.5K0.5)NbO3-(Bi0.5Na0.5)TiO3 Ceramics

2011 ◽  
Vol 201-203 ◽  
pp. 2772-2775
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Electrical Properties ◽  
Coupling Coefficient ◽  
High Frequency ◽  
Electromechanical Coupling ◽  
Lead Free ◽  
Coupling Coefficients ◽  
Lead Free Ceramics ◽  
Thickness Mode ◽  
Planar Mode

Lead-free (1-x)(Na0.5K0.5)NbO3-x(Na0.5Bi0.5)TiO3(x=0.02, 0.04, 0.06, 0.08, and 0.10) ceramics have been prepared by the conventional mixed oxide process. For 0.98(Na0.5K0.5)NbO3-0.02(Na0.5Bi0.5)TiO3ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.33 and 0.62, respectively, after sintering at 1100°C for 5 h. The ratio of the thickness coupling coefficient to the planar coupling coefficient is 1.88. Our results show that 0.98(Na0.5K0.5)NbO3-0.02(Na0.5Bi0.5)TiO3solid solution ceramics are promising lead-free ceramics for high-frequency electromechanical transducer applications.

Effect of Nb2O5 Addition on the Physical and Electrical Properties of Lead-Free (Na0.5Bi0.5)TiO3 -Ba(Sn0.08Ti0.92)O3 Ceramics

2011 ◽  
Vol 393-395 ◽  
pp. 72-75
Author(s):  
Chun Huy Wang
Keyword(s):  
Coupling Coefficient ◽  
High Frequency ◽  
Electromechanical Coupling ◽  
Hexagonal Phase ◽  
Lead Free ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Free Ceramics ◽  
Thickness Mode

In this paper, (Na0.5Bi0.5)TiO3 -based solid solutions were studied to improve piezoelectric properties as those found in the PbZrO3-PbTiO3 (PZT)-based ceramics. The 0.98(Na0.5Bi0.5)TiO3 -0.02Ba(Sn0.08Ti0.92)O3 (0.98NBT-0.02BST) ceramics with the addition of 0~2.0 wt.% Nb2O5 have been prepared following the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Sn0.08Ti0.92)O3 diffuse into the lattice of (Na0.5Bi0.5)TiO3 to form a solid solution, in which a hexagonal phase with a perovskite structure was found. For 0.98NBT-0.02BST ceramics with the addition of 0.5 wt.% Nb2O5, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.12 and 0.28, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 2.3. It is obvious that 0.98NBT-0.02BST ceramics by adding low quantities of Nb2O5 are one of the promising lead-free ceramics for high frequency electromechanical transducer applications.

Sb5+ Modified Phase Transition in (Li, Na, K)(Nb1-xSbx)O3 Piezoelectric Ceramics

2016 ◽  
Vol 848 ◽  
pp. 339-343
Author(s):  
Xiao Kun Zhao ◽  
Bo Ping Zhang ◽  
Lei Zhao ◽  
Li Feng Zhu
Keyword(s):  
Phase Transition ◽  
Phase Boundary ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Electromechanical Coupling Coefficient ◽  
Second Phase ◽  
Phase Transition Temperatures ◽  
Two Peaks ◽  
Planar Mode

The modified behavior of the phase transition temperatures (TO-T and/or TC) between orthorhombic (O), tetragonal (T) and cubic (C) that caused by doping Sb5+ in (Li0.052Na0.493K0.455)(Nb1-xSbx)O3 (LNKNSx) ceramics was reported in the present investigation. The results show that differing from the insensitive TO-T to the Sb5+ content, TC splits into two peaks TCI and TCII when doping Sb5+. The decreased TCI by raising x may be ascribed to the Sb-rich grains and the settled TCII round 480 °C resulting from the Sb-lack ones. The enhanced piezoelectric coefficient d33 value of 263 pC/N and planar mode electromechanical coupling coefficient kp value of 42.5% at x=0.052 can be attributed to the polymorphic phase boundary (PPB) behavior with an appropriate ratio between T and O phases without any second phase.

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