Dielectric and Piezoelectric Properties of Na0.42K0.08Bi0.5 TiO3 and Na0.45K0.05Bi0.5TiO3 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 251-254 ◽  
Author(s):  
Su Chuan Zhao ◽  
Lina Zhang ◽  
Guo Rong Li ◽  
Liao Ying Zheng ◽  
Ai Li Ding

Na0.42K0.08Bi0.5TiO3 and Na0.45K0.05Bi0.5TiO3 ceramics were fabricated by the solid-state reaction. The structures were determined by X-ray diffraction. Dielectric, ferroelectric and piezoelectric properties of the ceramics were measured and discussed. The ceramics have a single perovskite phase with rhombohedral symmetry at room temperature. The thermal variations of the permittivity follow the law 1/ e − 1/ em = C(T − Tm)2 which is the character of typical relax ferroelectrics, when temperature is higher than the temperature of the maximum of dielectric constant (Tm). The depolarization temperature (Td) of spontaneous polarization is 215oC for Na0.45K0.05Bi0.5TiO3 and 152oC for Na0.42K0.08Bi0.5TiO3 respectively. There exist two different dielectric behaviors of the Na0.42K0.08Bi0.5TiO3 ceramic, without and after poling. Na0.45K0.05Bi0.5TiO3 possesses relatively high kt and Td. The use for device application has been indicated.

2011 ◽  
Vol 284-286 ◽  
pp. 1408-1411
Author(s):  
Yan Li ◽  
Yan Jie Zhang ◽  
Rui Qing Chu ◽  
Zhi Jun Xu ◽  
Qian Chen ◽  
...  

La2O3-doped lead-free 0.82Bi0.5Na0.5TiO3-0.18Bi0.5K0.5TiO3(abbreviated to 0.82BNT-0.18BKT) piezoelectric ceramics were synthesized by the conventional mixed-oxide method, and the effect of La2O3addition on the dielectric and piezoelectric properties was investigated. X-ray diffraction (XRD) patterns show that La2O3diffuses into the lattice of the 0.82BNT-0.18BKT ceramics to form a solid solution with a pure perovskite structure. SEM images indicate that the grain size of the 0.82BNT-0.18BKT ceramics increased with the addition of La2O3doping. The electrical properties of 0.82BNT-0.18BKT ceramics have been greatly improved by certain amount of La2O3substitutions. At room temperature, the 0.82BNT-0.18BKT ceramics doped with 0.25 wt. % La2O3exhibited the optimum properties with high piezoelectric constant (d33= 142 pC/N) and high planar coupling factor (kp= 0.23).


2011 ◽  
Vol 415-417 ◽  
pp. 1983-1987
Author(s):  
Xiao Na Wang ◽  
Qing Chi Sun ◽  
Wei Bing Ma ◽  
Tao Liu ◽  
Yong Zhang ◽  
...  

We reported that Bi(Mg1/2Ti1/2)O3–PbTiO3(BMT-PT) systems had high piezoelectric, dielectric performances and high Curie temperature. The phase structure of the system was identified by X-ray diffraction analysis. The piezoelectric and dielectric properties were also investigated. The results showed that 0.6BMT–0.4PT (Mg/Ti = 0.5:0.5) with 1mol% MnO2was the optimum composition which exhibited the highest curie temperature Tc = 511 °C and the stable temperature of dielectric loss reached to 500 °C. Further, the dielectric and piezoelectric properties of this composition were given as follows:kp = 22.5%;εr= 734; room temperature d33= 131.3 pC/N; tanδ = 1.96%.


RSC Advances ◽  
2018 ◽  
Vol 8 (43) ◽  
pp. 24286-24296 ◽  
Author(s):  
Sushmita Dwivedi ◽  
Tanvi Pareek ◽  
Sunil Kumar

Room temperature powder X-ray diffraction patterns of (1 – x)K0.5Na0.5NbO3–xBi(Zn0.5Ti0.5)O3 system.


2013 ◽  
Vol 582 ◽  
pp. 84-87 ◽  
Author(s):  
Ryuta Mitsui ◽  
Ichiro Fujii ◽  
Kouichi Nakashima ◽  
Nobuhiro Kumada ◽  
Yoshihiro Kuroiwa ◽  
...  

1-x-y)BaTiO3-xBi (Mg1/2Ti1/2)O3-yBiFeO3 ceramics were prepared by a conventional solidstate synthesis, and crystal structure and electric properties were investigated. Synchrotron X-ray diffraction pattern revealed that a single perovskite phase was obtained for samples at x=0.05-0.15, y=0.46.5-73.5. Splitting of the (111) peak was observed when (x, y) = (0.050, 0.685) and (0.050, 0.735) indicating that crystal structure of samples changed from a pseudo-cubic phase to a rhombohedral phase with increasing BF. As the BF content increased, the Curie temperature increased. The largest maximum strain (Smax) over the applied maximum electric field (Emax) value (Smax / Emax) of 300 pm/V was observed for 0.365BT-0.050BMT-0.585BF at 25 °C and 1Hz with the Curie temperature of 390 °C.


2020 ◽  
Vol 42 (5) ◽  
pp. 634-634
Author(s):  
Fares Kahoul Fares Kahoul ◽  
Louanes Hamzioui Louanes Hamzioui ◽  
Abderrezak Guemache Abderrezak Guemache ◽  
Michel Aillerie and Ahmed Boutarfaia Michel Aillerie and Ahmed Boutarfaia

Modified-PZT ceramics with a formula (1-x)Pb(Zr0.53 Ti0.47)O3-xSr(Fe2/3, Nb1/3)O3 (doped with isovalent: Sr2+, acceptor: Fe3+ and Donor: Nb5+ ions) abbreviated as (1-x)PZT-xSFN binary system with varying x (x= 0.02, 0.04, 0.06, 0.08 and 0.10) located near the morphotropic phase boundary (MPB) were prepared by a traditional process in a solid state. All the samples were sintered at a temperature of 1200and#176;C during 2 h. The phase structure, the dielectric and piezoelectric properties of the system were studied. In-phase analysis used X-ray diffraction (XRD) at room temperature indicated that the structure of phase of sintered PZT-SFN ceramics was formed in single-phase with a crystalline structure tetragonal. Raman spectroscopy confirms the presence of this tetragonal phase. The optimum electrical parameters are obtained at 0.94Pb(Zr0.53Ti0.47)O3-0.06Sr(Fe2/3, Nb1/3)O3 system: kp= 66.10 %, d31= 145 pC/N, Qm= 473, tanδ= 1.11 %, and ɛr= 1009.


2011 ◽  
Vol 01 (03) ◽  
pp. 345-349 ◽  
Author(s):  
ERIC A. PATTERSON ◽  
DAVID P. CANN

Solid solutions based on Li , Ta and Sb -doped (K0.5Na0.5)NbO3 (KNN) lead-free perovskite systems were created using standard solid-state methods. X-ray diffraction was used to confirm that all compositions were single phase and to verify the phase transition from tetragonal to cubic at TC = 302° C . The three compositions examined, originally developed by Saito and Li , were shown to be strongly ferroelectric with sharp peaks in permittivity present at the Curie temperature. The optimum composition had loss tangent values below 5% up to 100 kHz at room temperature. Bipolar hysteresis measurements showed high values for both maximum polarization (25 and 21 μC/cm2) and remenant polarizations (20 and 16 μC/cm2) for undoped and 0.2 wt% CuO -doped samples. Maximum strain values of greater than 0.23% were observed.


2016 ◽  
Vol 690 ◽  
pp. 126-130 ◽  
Author(s):  
Chavalit Suksri ◽  
Piewpan Parjansri ◽  
Sutatip Thonglem ◽  
Uraiwan Intatha ◽  
Sukum Eitssayeam ◽  
...  

Lead-free (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics were studied and synthesized by the seed-induced method. NaNbO3 crystal was used as seed and prepared by molten salt synthesis (MSS). The average particles size of NaNbO3 seed crystal was about 1-3 mm. Then, the NaNbO3 seed was mixed with KNN powder and ball milled for 24 h. The mixed powder was calcined at 700-900 °C and sintered at 1100 °C. The phase structure and morphology of the ceramics were investigated by X-ray diffraction and scanning electron microscope and the electrical properties were studied. The results indicated that all samples showed a pure perovskite phase. The highest density of the ceramic was 93% compared to the theoretical density. The results showed that NaNbO3seed crystal improved piezoelectric properties of KNN ceramics.


2007 ◽  
Vol 21 (06) ◽  
pp. 931-945 ◽  
Author(s):  
K. SAMBASIVA RAO ◽  
P. MURALI KRISHNA ◽  
D. MADHAVA PRASAD ◽  
JOON HYUNG LEE

Ferroelectric, hysteresis, impedance spectroscopy parameters, AC conductivity, and piezoelectric properties in the ceramics of Pb 0.74 K 0.52 Nb 2 O 6 and Pb 0.74 K 0.13 Sm 0.13 Nb 2 O 6 have been studied. X-ray diffraction study reveals single phase with the orthorhombic structure. The samples were characterized for ferroelectric and impedance spectroscopy properties from room temperature to 600°C. Cole–Cole plots (Z″ versus Z′) are drawn at different temperatures. The results obtained are analyzed to understand the conductivity mechanism in both the samples. The piezoelectric constant d33 has been found to be 96 × 10-12 C/N in PKN.


2013 ◽  
Vol 368-370 ◽  
pp. 760-763
Author(s):  
Chun Huy Wang ◽  
Ming Qiu Wei

(Na0.5K0.5)NbO3 with Bi0.5(Na0.97K0.03)0.5TiO3 with x≤0.05 has been prepared by the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all the Bi(Na0.97K0.03)TiO3 diffuses into the lattice of (Na0.5K0.5)NbO3 to form a solid solution with a perovskite structure. A morphotropic phase boundary (MPB) between orthorhombic (O) and rhombohedral (R) was found at the composition 0.98(Na0.5K0.5)NbO3-0.02Bi0.5(Na0.97K0.03)0.5TiO3 [abbreviated as 0.98NKN-0.02BNKT] with correspondingly enhanced dielectric and piezoelectric properties. For 0.98NKN-0.02BNKT ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.33 and 0.49, respectively, after sintering at 1100 oC for 3 h. The ratio of the thickness coupling coefficient to the planar coupling coefficient is 1.48. With suitable Bi0.5(Na0.97K0.03)0.5TiO3 concentration, a dense microstructure and good electrical properties are obtained.


2005 ◽  
Vol 475-479 ◽  
pp. 1153-1156 ◽  
Author(s):  
Shi Xi Zhao ◽  
Qiang Li ◽  
Feng Bing Song

Single perovskite phase PMN-PT powders had been synthesized using molten salts method. The powders of PMN-PT synthesized by MSS had submicrometer particle size and high sinterability, which beneficial to an enhancement of the densification process and a decrease of the sintering temperatures. These advantages have an important bearing on the dielectric properties of these materials. The density of ceramics sintered at 1175°C was up to 98% of the theoretical density. These ceramics had excelled dielectric and piezoelectric properties.


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