scholarly journals Current Development in Lead-FreeBi0.5(Na,K)0.5TiO3-Based Piezoelectric Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Ngo Duc Quan ◽  
Luong Huu Bac ◽  
Duong Van Thiet ◽  
Vu Ngoc Hung ◽  
Dang Duc Dung
Keyword(s):  
Solid Solution ◽  
Piezoelectric Properties ◽  
Domain Switching ◽  
Piezoelectric Materials ◽  
Secondary Phase ◽  
Lead Free ◽  
Secondary Phases ◽  
Current Development ◽  
Cubic Phases

The lead-free piezoelectric ceramics display good piezoelectric properties which are comparable with Pb(Zr,Ti)O3(PZT) and these materials overcome the hazard to the environment and human health. The Bi0.5(Na,K)0.5TiO3(BNKT) is rapidly developed because of good piezoelectric, ferroelectric, and dielectric properties compared to PZT. The origin of giant strain of BNKT piezoelectric materials was found at morphotropic phase boundary due to crystal change from tetragonal to orthorhombic and/or precipitation of cubic phases, in addition to domain switching mechanism. The dopants or secondary phases withABO3structure as solid solution are expected to change the crystal structure and create the vacancies which results in enhancement of the piezoelectric properties. In this work, we reviewed the current development of BNKT by dopants and secondary phase as solid solution. Our discussion will focus on role of dopants and secondary phase to piezoelectric properties of BNKT. This result will open the direction to control the properties of lead-free piezoelectric materials.

Phase diagram determination of large piezoelectric response in BHT-BCT ceramics

2019 ◽  
Vol 12 (05) ◽  
pp. 1950070 ◽  
Author(s):  
Zhonghua Dai ◽  
Dingyan Li ◽  
Jinglong Xie ◽  
Weiguo Liu ◽  
Shaobo Ge ◽  
...  
Keyword(s):  
Phase Diagram ◽  
High Performance ◽  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Electronic Devices ◽  
Lead Free ◽  
Piezoelectric Response ◽  
Cubic Phases ◽  
Co Doped

High-performance lead-free piezoelectric materials are environmentally friendly and in great demand for electronic devices. In this study, the phase diagram and properties of Hf, Ca co-doped BaTiO3 (BHT-BCT) were investigated. A triple-point morphotropic phase boundary separating the rhombohedral, tetragonal and cubic phases for the (1-[Formula: see text])Ba(Ti0.85Hf0.15)O3-[Formula: see text](Ba0.7Ca0.3)TiO3 system exited at [Formula: see text] High piezoelectric properties with piezoelectric coefficients [Formula: see text] (572pC/N) and Curie temperature [Formula: see text] (90∘C) of 0.55Ba(Ti0.85Hf0.15)O3-0.45(Ba0.7Ca0.3)TiO3 are achieved in the BaTiO3-based ceramics.

Effect of Bi2O3 Addition on the Microstructure and Electrical Properties of Lead-Free (Na0.5K0.5)NbO3-Bi0.5(Na0.93K0.07)0.5TiO3 Ceramics

2013 ◽  
Vol 479-480 ◽  
pp. 3-7
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
Coupling Coefficients ◽  
Electromechanical Transducer ◽  
Lead Free Ceramics ◽  
Thickness Mode ◽  
Planar Mode

In the present study, various quantities of Bi2O3were added into 0.98(Na0.5K0.5)NbO3-0.02Bi(Na0.93K0.07)TiO3(0.98NKN-0.02BNKT) ceramics. It was found that 0.98NKN-0.02BNKTwith the addition of 0~0.5 wt.% Bi2O3exhibit relatively good piezoelectric properties. For 0.98NKN-0.02BNKT ceramics, the electromechanical coupling coefficients of the planar modekpand the thickness modektreach 0.40 and 0.47,respectively. For 0.98NKN-0.02BNKT ceramics with the addition of 0.3 wt.% Bi2O3, the electromechanical coupling coefficients ofthe planar modekpand the thickness modektreach 0.50 and 0.53, respectively. It is obvious that 0.98NKN-0.02BNKT solid solution ceramics by adding low quantities of Bi2O3is one of the promising lead-free ceramics for electromechanical transducer applications.

FLEXOELECTRIC COMPOSITE — A NEW PROSPECT FOR LEAD-FREE PIEZOELECTRICS

2010 ◽  
Vol 03 (01) ◽  
pp. 79-81 ◽  
Author(s):  
BAOJIN CHU ◽  
WENYI ZHU ◽  
NAN LI ◽  
L. ERIC CROSS
Keyword(s):  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Physical Phenomenon ◽  
Mechanical Strain ◽  
Dielectric Materials ◽  
Electric Polarization ◽  
Lead Free ◽  
Piezoelectric Response ◽  
Bst Ceramics ◽  
Better Than

Flexoelectricity describes the physical phenomenon of the generation of electric polarization from mechanical strain gradient in solid insulators. In common dielectric materials, the flexoelectric coefficient is trivially small ~10-10 C/m. In Ba(Sr,Ti)O 3 (BST) ceramics, flexoelectric coefficient up to 10-4 C/m was observed. Such high coefficient makes it possible to design high piezoelectric response flexoelectric composites. In this letter, we will demonstrate that the newly designed flexoelectric composites could have piezoelectric properties better than conventional piezoelectric materials.

Material Design of Alkaline Niobate Piezoelectric Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1879-1882 ◽  
Author(s):  
Kenichi Kakimoto
Keyword(s):  
Solid Solution ◽  
Wide Temperature Range ◽  
Piezoelectric Properties ◽  
Tungsten Bronze ◽  
Material Design ◽  
Research Field ◽  
Lead Free ◽  
Ceramic System ◽  
Research Activity ◽  
Temperature Range

Nb-based systems have been considered to be the most attractive ceramic system in the research field of lead-free piezoceramics, since excellent piezoelectric properties were reported in (Li,Na,K)NbO3-based solid solution (LNKN) systems. This article reviews the characteristic and recent research activity for several kinds of the niobate systems including LiNbO3, NaNbO3, KNbO3, tungsten-bronze niobate. The importance of material design for enhancement of piezoelectric properties and their stability in the wide temperature range is also described for LNKN system.

Enhanced Piezoelectric Properties of Lead-Free Piezoelectric Materials by Microstructure Control

2010 ◽  
Vol 402 (1) ◽  
pp. 121-129 ◽  
Author(s):  
Satoshi Wada ◽  
Shigehito Shimizu ◽  
Petr Pulpan ◽  
Nobuhiro Kumada ◽  
Daisuke Tanaka ◽  
...  
Keyword(s):  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Microstructure Control

The Effect of Heat-Treatment on the Phase Stability of Fe-28Al-15Si-2Mo Alloy

2020 ◽  
Vol 405 ◽  
pp. 80-85
Author(s):  
Věra Vodičková ◽  
Martin Švec ◽  
Pavel Hanus ◽  
Petra Pazourková Prokopčáková
Keyword(s):  
Solid Solution ◽  
Phase Stability ◽  
Secondary Phase ◽  
Hardness Measurement ◽  
Secondary Phases ◽  
Solid Solution Strengthening ◽  
High Temperature Mechanical Properties ◽  
Molybdenum Addition ◽  
Bulk Hardness ◽  
Solution Strengthening

The structures of Fe-28Al-15Si-2Mo iron aluminide in as cast state and in three states after heat-treatments were investigated for the verification of secondary phases stability. Short-term (at 1000 °C for 24 h and at 1200 °C for 2 h) as well as long-term (at 800 °C for 100 h) annealing were performed. Molybdenum addition enhances the high-temperature mechanical properties due to solid solution strengthening, however the mechanism of hardening could be modified (to solid solution strengthening + strengthening by incoherent precipitates) by another alloying element (f. e. Si or C). The phase compositions of alloys were described by means of scanning electron microscopy equipped with energy dispersive analysis. The complex Fe-Si-Mo carbides were found in the structure. The bulk hardness measurement and image analysis were performed for the verification of secondary phase stability. Particles became coarse with increasing temperature of annealing.

Lead Free (Bi, Na)TiO3–BiAlO3 Ceramics for Piezoelectric Application

2020 ◽  
Vol 15 (4) ◽  
pp. 459-462
Author(s):  
Jae-Hoon Ji ◽  
Don-Jin Shin ◽  
Sang-Kwon Lee ◽  
Sang-Mo Koo ◽  
Jae-Geun Ha ◽  
...  
Keyword(s):  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Electromechanical Coupling Coefficient ◽  
Substitution Effects ◽  
Sensors And Actuators ◽  
Device Applications ◽  
Piezoelectric Devices ◽  
Piezoelectric Charge

In this research, substitution effects of BiAlO3 with (Bi, Na)TiO3 piezoelectric ceramics was investigated for the sensors and actuators applications. (Bi,Na)TiO3 material has been employed for the piezoelectric devices applications because of their high piezoelectric charge constant, d33, of 88 pC/N, electromechanical coupling coefficient, kp, of 22% and inverse piezoelectric charge constant of 498 pm/V. As a piezoelectric material, (Bi, Na)TiO3 has perovskite structure with tetragonal basis. The improvement of piezoelectric and inverse piezoelectric properties is important for industrial device applications. Therefore, in this research, we have tried to increase functional and electrical properties of (Bi, Na)TiO3 piezoelectric materials by substituting BiAlO3 dopants. As a result, the piezoelectric constant was increased up to 140 pC/N, and the densification was increased up to 5.92 g/cm3 .

Dielectric and Piezoelectric Properties of (Na,Ba)(Nb,Ti)O3 Lead-Free Piezoelectric Ceramics

2010 ◽  
Vol 445 ◽  
pp. 55-58 ◽  
Author(s):  
Rintaro Aoyagi ◽  
Makoto Iwata ◽  
Masaki Maeda
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Dielectric And Piezoelectric Properties

(Na1-xBax)(Nb1-xTix)O3 (NNBTx; x=0.0-0.21) solid-solution ceramics were synthesized and their crystal structure, dielectric properties and piezoelectric properties were investigated. The crystal structure at room temperature of NNBTx varied from orthorhombic to tetragonal with increasing BaTiO3 content x. The phase boundary between orthorhombic and tetragonal at room temperature was confirmed BT content between x=0.08 and 0.09. For x>0.05, it was found that the Curie temperature was decreased with increasing x. The highest electromechanical coupling factor, kp, and the largest piezoelectric constant, d33, were obtained at x=0.09-0.10.

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