Piezoelectric and Electrical Properties of Lead-Free (Na0.5K0.5)NbO3- Bi0.5(Na0.80K0.20)0.5TiO3 Ceramics

2011 ◽  
Vol 230-232 ◽  
pp. 12-15
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Solution System ◽  
Solid Solution System ◽  
Dielectric And Piezoelectric Properties

Extending the investigations on (Na0.5K0.5)NbO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Na0.5K0.5)NbO3–Bi0.5(Na0.80K0.20)0.5TiO3[NKN-BNKT]. (Na0.5K0.5)NbO3with 2 ~ 6 mol% Bi0.5(Na0.80K0.20)0.5TiO3has been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between orthorhombic (O) and tetragonal (T) was found at the composition 0.97NKN-0.03BNKT with correspondingly enhanced dielectric and piezoelectric properties. The electromechanical coupling factor and dielectric constant are higher for compositions near the MPB. The dielectric constant (εr), planar coupling coefficient (kp) and thickness coupling coefficient (kt)of 0.97NKN-0.03BNKT ceramics were 1483, 32% and 31%, respectively.

Electrical and Physical Properties of Lead-Free (Na0.5K0.5)NbO3- Bi0.5(Na0.93K0.07)0.5TiO3 Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1351-1354
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Solution System ◽  
Solid Solution System ◽  
Dielectric And Piezoelectric Properties

Extending the investigations on (Na0.5K0.5)NbO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Na0.5K0.5)NbO3–Bi0.5(Na0.93K0.07)0.5TiO3 [NKN-BNKT]. (Na0.5K0.5)NbO3 with 2 ~ 6 mol% Bi0.5(Na0.93K0.07)0.5TiO3 has been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between orthorhombic (O) and rhombohedral (R) was found at the composition 0.98NKN-0.02BNKT with correspondingly enhanced dielectric and piezoelectric properties. The electromechanical coupling factor and dielectric constant are higher for compositions near the MPB. The dielectric constant (KT33), planar coupling coefficient (kp) and thickness coupling coefficient (kt)of 0.98NKN-0.02BNKT ceramics were 1040, 47% and 48%, respectively.

Dielectric and Piezoelectric Properties of Lead-Free (Na0.5K0.5)NbO3- Bi0.5(Na0.85K0.15)0.5TiO3 Ceramics

2011 ◽  
Vol 211-212 ◽  
pp. 152-155
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Solid Solution System ◽  
Dielectric And Piezoelectric Properties

Extending the investigations on (Na0.5K0.5)NbO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Na0.5K0.5)NbO3–Bi0.5(Na0.85K0.15)0.5TiO3[NKN-BNKT]. (Na0.5K0.5)NbO3with 2 ~ 6 mol% Bi0.5(Na0.85K0.15)0.5TiO3has been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between orthorhombic (O) and hexagonal (H) was found at the composition 0.96NKN-0.04BNKT with correspondingly enhanced dielectric and piezoelectric properties. The electromechanical coupling factor and dielectric constant are higher for compositions near the MPB. The dielectric constant (KT33), planar coupling coefficient (kp) and thickness coupling coefficient (kt)of 0.96NKN-0.04BNKT ceramics were 1273, 34% and 38%, respectively.

Electrical and Physical Properties of Lead-Free (Na0.5K0.5)NbO3- Bi0.5(Na0.90K0.10)0.5TiO3 Ceramics

2014 ◽  
Vol 602-603 ◽  
pp. 791-794
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Rhombohedral Phase ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Lead Free ◽  
Structure Changes ◽  
Solid Solution System

Extending the investigations on (Na0.5K0.5)NbO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Na0.5K0.5)NbO3Bi0.5(Na0.90K0.10)0.5TiO3 [NKN-BNK. (Na0.5K0.5)NbO3 with 1 ~ 5 mol% Bi0.5(Na0.90K0.10)0.5TiO3 has been prepared following the conventional mixed oxide process. It can be concluded that the NKN-BNKT ceramics have orthorhombic structures in the case x 0.03. With increasing BNKT content (x=0.04 to 0.05), however, the structure changes from orthorhombic to rhombohedral phase. Above results demonstrated that the MPB between orthorhombic and rhombohedral phases exits in the solid solution with the BNKT content of x=0.03. At the MPB composition, the cryctalline structure of ceramics is considered to be a coexistence of orthorhombic and rhombohedral phase. Owing to the phase coexistence at the phase boundary, there exists a different symmetry regions (DSR) near the MPB. The DSR boundary motion increases the dielectric permittivity and piezoelectric coefficients. The electromechanical coupling factor and dielectric constant are higher for compositions near the MPB. The dielectric constant (KT33), planar coupling coefficient (kp), thickness coupling coefficient (kt) and piezoelectric constant (d33)of 0.98NKN-0.02BNKT ceramics were 1180, 30%, 58%, and 180, respectively.

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.

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

2011 ◽  
Vol 239-242 ◽  
pp. 3240-3243 ◽  
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Coupling Coefficient ◽  
Piezoelectric Properties ◽  
Coupling Factor ◽  
Mechanical Quality Factor ◽  
Lead Free ◽  
Solution System ◽  
Solid Solution System ◽  
Mechanical Quality ◽  
Quality Factor Q

Extending the investigations on (Bi0.5Na0.5)TiO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Bi0.5Na0.5)TiO3–(Bi0.5K0.5)TiO3[BNT-BKT]. (Bi0.5Na0.5)TiO3with 7~ 30 mol% (Bi0.5K0.5)TiO3ceramics have been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between rhombohedral (R) and tetragonal (T) was found at the composition 0.82BNT-0.18BKT with correspondingly enhanced piezoelectric properties. The electromechanical planar coupling factor is higher for compositions near the MPB. The mechanical quality factor (Qm), planar coupling coefficient (kp) and thickness coupling coefficient (kt) of 0.82BNT-0.18BKT ceramics were 125, 28.8% and 47.4%, respectively.

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.

Structure and Electrical Properties of Lead-Free (Bi0.5Na0.5)TiO3-Ba(Sn,Ti)O3 Ceramics

2010 ◽  
Vol 148-149 ◽  
pp. 232-235 ◽  
Author(s):  
Chun Huy Wang
Keyword(s):  
Solid Solution ◽  
Electrical Properties ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Rhombohedral Phase ◽  
Lead Free ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
Dense Microstructure ◽  
Solid Solution System

Extending the investigations on (Bi0.5Na0.5)TiO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Bi0.5Na0.5)TiO3-Ba(Sn,Ti)O3. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Sn,Ti)O3 diffuses into the lattice of (Bi0.5Na0.5)TiO3 to form a solid solution, in which a rhombohedral phase with a perovskite structure was found. It was found that the samples with a low content of Ba(Sn0.06Ti0.94)O3 exhibit relatively good physical and electric properties. For 0.98(Bi0.5Na0.5)TiO3-0.02Ba(Sn0.06Ti0.94)O3 ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.16 and 0.57, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 3.56. For 0.98(Bi0.5Na0.5)TiO3-0.02Ba(Sn0.06Ti0.94)O3 ceramics, the relative density and the thickness coupling coefficient kt reach 98.1% and 0.58, respectively, at the sintering of 1100oC for 5 h. With suitable Ba(SnxTi1-x)O3 concentration and sintering condition, a dense microstructure and good electrical properties were obtained.

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.

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