scholarly journals Structure, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-based lead-free ceramics

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.

2010 ◽  
Vol 03 (01) ◽  
pp. 49-53 ◽  
Author(s):  
DUNMIN LIN ◽  
K. W. KWOK

Lead-free ( Bi 0.5 Na 0.5)1-x-y-z Ba x( Bi 0.5 Li 0.5)y Sr z TiO 3 ceramics were prepared by an ordinary sintering method and their structure and piezoelectric properties have been studied. X-ray diffraction patterns show that Ba 2+, Li + and Sr 2+ diffuse into the Bi 0.5 Na 0.5 TiO 3 lattices to form a solid solution with a pure perovskite structure and a morphotropic phase boundary (MPB) between rhombohedral and tetragonal phases is formed at 0.04 ≤ x ≤ 0.08 and z < 0.06. The content of Li + has no obvious influence on the crystal structure of the ceramics. The ceramics situated within the MPB exhibit a lower coercive field E c and a larger remanent polarization P r . Because of the formation of the MPB, lower E c and larger P r , the ceramics with x = 0.06, y = 0.075 - 0.125 and z = 0-0.02 possess improved piezoelectric properties. The optimum d33 (235 pC/N ) and k p (36.3%) are reached at x/y/z = 0.06/0.125/0.02 and 0.06/0.075/0.02, respectively. The deformed P–E loop is also observed near or above T d .


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.


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).


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 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%.


2012 ◽  
Vol 05 (04) ◽  
pp. 1250041 ◽  
Author(s):  
WEI XU ◽  
YANG LI ◽  
JIAN-MIN FENG ◽  
YE-JING DAI

In this study, lead-free piezoelectric ceramics ( Na0.52K0.44Li0.04 )( Nb0.88Sb0.08Ta0.04 ) O3 -doped 0.52 Ba ( Zr 0.2 Ti 0.8) O 3-0.48( Ba 0.7 Ca 0.3) TiO 3( BCZT -x KNNLST ) are investigated. The effects of the KNNLST addition on the microstructures and the electrical properties of the ceramics sintered at the temperature as low as 1350°C are studied. The X-ray diffraction data show that the addition of KNNLST could diffuse into BCZT lattice and a pure perovskite phase is formed. With the increase of KNNLST addition, the average grain size is first increased and afterwards decreased. The ceramics with x = 0.005 exhibit a good piezoelectric behavior of d 33 ~ 464 pC/N and k p ~ 0.44 after three month's aging, which indicates the BCZT -x KNNLST ceramics could be promising for lead-free practical applications.


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.


2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.


1974 ◽  
Vol 29 (12) ◽  
pp. 1771-1777 ◽  
Author(s):  
N. C. Haider ◽  
S. H. Hunter

Powder Cd of 99.999% purity was prepared at room temperature (25 °C) and x-ray diffraction patterns were obtained using CuKaα radiation with Ni-filter. The line broadening was analyzed after incorporating the appropriate correction factors. At room temperature Cd was found to have large particle size (653 A), small root mean square strain (.001), small deformation fault probability a (.003). and negligible growth fault probability β(0). Compared to other hep metals which have been studied earlier and which have higher melting temperatures, metal Cd is much less affected by mechanical deformation at room temperature.


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