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

Coupling Factor ◽

Lead Free ◽

Solution System ◽

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)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.

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

10.4028/www.scientific.net/amr.230-232.12 ◽

2011 ◽

Vol 230-232 ◽

pp. 12-15

Author(s):

Chun Huy Wang

Keyword(s):

Solid Solution ◽

Dielectric Constant ◽

Coupling Coefficient ◽

Coupling Factor ◽

Lead Free ◽

Solution System ◽

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)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(Na0.90K0.10)0.5TiO3 Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.791 ◽

2014 ◽

Vol 602-603 ◽

pp. 791-794

Author(s):

Chun Huy Wang

Keyword(s):

Solid Solution ◽

Dielectric Constant ◽

Coupling Coefficient ◽

Rhombohedral Phase ◽

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.445.55 ◽

2010 ◽

Vol 445 ◽

pp. 55-58 ◽

Cited By ~ 4

Author(s):

Rintaro Aoyagi ◽

Makoto Iwata ◽

Masaki Maeda

Keyword(s):

Crystal Structure ◽

Solid Solution ◽

Dielectric Properties ◽

Room Temperature ◽

Coupling Factor ◽

Lead Free ◽

(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

10.4028/www.scientific.net/amr.239-242.3240 ◽

2011 ◽

Vol 239-242 ◽

pp. 3240-3243 ◽

Cited By ~ 4

Author(s):

Chun Huy Wang

Keyword(s):

Solid Solution ◽

Coupling Coefficient ◽

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.

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

10.4028/www.scientific.net/amr.887-888.289 ◽

2014 ◽

Vol 887-888 ◽

pp. 289-293

Author(s):

Jing Chang Zhao ◽

Zhen Lai Zhou

Keyword(s):

Electrical Properties ◽

Piezoelectric Ceramics ◽

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

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.67.34 ◽

2010 ◽

Vol 67 ◽

pp. 34-41

Author(s):

Toshio Ogawa ◽

Masahito Furukawa ◽

Takeo Tsukada

Keyword(s):

Bismuth Titanate ◽

Domain Switching ◽

Coupling Factor ◽

Lead Free ◽

Poling Field ◽

Lead Free Ceramics ◽

Titanate Ceramics ◽

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.

Effect of Sintering Temperature on the Structure and Piezoelectric Properties of Lead-Free 0.97K0.5Na0.5NbO3-0.03AlFeO3 Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.822 ◽

2014 ◽

Vol 602-603 ◽

pp. 822-825

Author(s):

Ling Peng ◽

Min Hong Jiang ◽

Zheng Fei Gu ◽

Gang Cheng

Keyword(s):

Low Temperature ◽

Sintering Temperature ◽

Coupling Factor ◽

Lead Free ◽

Promising Candidate ◽

Ceramic Process ◽

Structure Density

Lead-free piezoelectric 0.97 K0.5Na0.5NbO3-0.03 AlFeO3(KNN-AF) ceramics were prepared at low temperature of 980 °C to 1020 °C by the conventional ceramic process. The effect of sintering temperature on the crystal structure, density and electrical properties of the ceramics was investigated. The results indicate that KNN-AF ceramics sintered at an low temperature of 1000 °C exhibit high electrical and piezoelectric properties, with piezoelectric constantd33=116ρC/N, and electromechanical coupling factorkp= 32.9%, polarization (Pr) wasPr=21.8 μC/cm2and curie temperatureTC=382°C. This also indicates that KNN-AF ceramics are promising candidate materials for lead-free piezoelectric applications.

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

10.4028/www.scientific.net/amr.415-417.1051 ◽

2011 ◽

Vol 415-417 ◽

pp. 1051-1054

Author(s):

Chun Huy Wang

Keyword(s):

Solid Solution ◽

Coupling Coefficient ◽

High Frequency ◽

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.

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

10.4028/www.scientific.net/amr.287-290.801 ◽

2011 ◽

Vol 287-290 ◽

pp. 801-804 ◽

Cited By ~ 4

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 ◽

Planar Electromechanical Coupling Factor

Coupling Factor ◽

Lead Free ◽

Relative Dielectric Permittivity ◽

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.