scholarly journals Structural, microstructural and dielectric characterizations of (Bi0.5Na0.5)TiO3based lead-free ferroelectric ceramics

2021 ◽  
pp. 2140006
Author(s):  
B. R. Moya ◽  
A. C. Silva ◽  
A. Peláiz-Barranco ◽  
J. D. S. Guerra

(1–[Formula: see text]Bi[Formula: see text]Na[Formula: see text]TiO3–[Formula: see text]BaTiO3 lead-free ceramics have been obtained from the conventional solid-state reaction sintering method. The structural properties were investigated from X-ray diffraction and Raman spectroscopy techniques. Results revealed well-crystallized ceramic samples with perovskite structure. Microstructural properties, obtained from scanning electron microscopy measurements, have shown high density with very low porosity level. The dielectric response, analyzed as a function of the temperature and several frequencies, showed very broad peaks with a strong frequency dependence of the temperature for the maximum dielectric permittivity for the modified system. Results were analyzed considering the influence of the BaTiO3 content on the studied physical properties.

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 .


2013 ◽  
Vol 770 ◽  
pp. 258-261
Author(s):  
Pornsuda Bomlai

Ceramics with formula (1-x-y)[Na0.515K0.485]0.94Li0.06(Nb0.99Ta0.01)O3 (NKLNT) xMnO2yCuO (when x, y = 0, 0.005 and 0.01) were prepared by a reaction sintering method. The effects of doping level on sinterability and properties of NKLNT ceramics were studied. The results indicated that the co-doping of MnO2 and CuO was effective in promoting the densification of ceramics. Grain growth during secondary recrystallization was also affected, leading to larger grain size with x, y = 0.01 sample. X-ray diffraction data showed that the orthorhombic tetragonal morphotropic phase boundary existed in all the samples. At room temperature, the dielectric properties of NKLNT ceramics were improved by doping of appropriate MnO2 and CuO content. The temperature dependence of dielectric constant showed a decrease slightly in Curie temperature (TC) with increasing MnO2 and CuO content. The composition with x = 0.005, y = 0 exhibited favorable properties for the promising lead-free piezoelectric candidate material.


2011 ◽  
Vol 01 (04) ◽  
pp. 439-445 ◽  
Author(s):  
QIAN CHEN ◽  
ZHIJUN XU ◽  
RUIQING CHU ◽  
YONG LIU

The influence of (Li, Ce) doping on the electrical properties of bismuth layer Sr 2-x (Li, Ce) x/2 Bi4Ti5O18 [abbreviated to SBTi-(Li, Ce) X/2] ceramics was investigated. X-ray diffraction analysis showed that all the ceramic samples were single-phase compounds. The (Li, Ce) modification significantly decreased the dielectric loss of Sr2Bi4Ti5O18 ceramics and greatly improved the piezoelectric activity. At x/2 = 0.0125, the SBTi-(Li, Ce) x/2 ceramics exhibited the excellent properties with high remnant polarization (P r = 9.3 μC/cm2) and high Curie temperature (T c = 299°C). Meanwhile, the SBTi-(Li, Ce)0.0125 ceramics had the largest piezoelectric constant (d33 = 26 pC/N). The results showed that the SBTi-(Li, Ce) x/2 ceramic was a promising lead-free piezoelectric material.


2017 ◽  
Vol 898 ◽  
pp. 1591-1596
Author(s):  
Na Na Shao ◽  
Xi Yun He ◽  
Da Zhi Sun ◽  
Bin Xia ◽  
Xia Zeng ◽  
...  

Lead-free EO ceramics have been received increasing attentions from the view point of green environment in recent years. In this study, lead-free Ba6-1.5xLaxTi2Nb8O30 (0≤x≤7%) ceramics were synthesized by the conventional solid state reaction sintering method. The effects of lanthanum doping on the microstructure and electrical properties of Ba6Ti2Nb8O30 (BTN) ceramics were investigated and analyzed. The XRD results revealed that the lanthanum doping changed the BTN lattice parameters slightly. The sample grain size, dielectric constants (1kHz) and the temperature Tm gradually decreased with the increasing of lanthanum doped content. The optimized BLTN ceramic sample with x=4 mol % exhibited a good transparency and excellent electrical properties (Ps=6.41 μC/cm2, Pr=0.77 μC/cm2, and Ec=3.80 kV/cm).


2016 ◽  
Vol 675-676 ◽  
pp. 544-547
Author(s):  
Supalak Manotham ◽  
Thanatep Phatungthane ◽  
Tawee Tunkasiri ◽  
Komsanti Chokethawat

The properties of modified Bi0.5Na0.5TiO3 (BNT) based lead-free ceramics were investigated. The BNT-based ceramics were prepared by a two-steps sintering method. The ceramics were sintered at T1=1373 K and T2= 1173 K for various dwell times (0, 2, 4, and 8h). The properties of the ceramics were characterized by many techniques. The ceramic samples exhibited a pure perovskite phase with rhombohedral symmetry. The microstructural analysis by a scanning electron microscopy (SEM), indicated that all ceramics had a similar microstructure. Piezoelectric and mechanical properties of the ceramics were improved at a suitable dwell time at T2.


2016 ◽  
Vol 872 ◽  
pp. 87-91
Author(s):  
Supalak Manotham ◽  
Tawee Tunkasiri ◽  
Pharatree Jaita ◽  
Pichitchai Butnoi ◽  
Denis Russell Sweatman ◽  
...  

The properties of modified Bi0.5Na0.5TiO3 (BNT) based lead-free ceramics were investigated. The BNT-based ceramics were prepared by a solid-state mixed oxide method Phase formation was determined by X-ray diffraction technique (XRD). The X-ray diffraction analysis of the ceramics suggested that all samples exhibited a perovskite structure without second phase. The value of dielectric constant increased with increasing in sintering temperature. Moreover, high sintering temperatures could improve ferroelectric properties of BNT base lead-free ceramics.


Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 419
Author(s):  
Jiameng Zhang ◽  
Yanan Hao ◽  
Meihua Bi ◽  
Guoyan Dong ◽  
Xiaoming Liu ◽  
...  

Ba (Zr0.2Ti0.8) O3-50% (Ba0.7Ca0.3) TiO3 (BZT-0.5BCT) ceramics with different doping contents of Pr3+ were prepared by the conventional solid-state reaction. The phase structure and crystallinity of the fabricated ceramics were investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Photoluminescence (PL) emission spectra were measured to analyze the PL characteristics. The strong intensities of a green band at 489 nm and a red band at 610 nm were observed. The maximum emission intensity of the PL spectrum was achieved in the BZT-0.5BCT ceramic with 0.2% mol of Pr3+ ions. Furthermore, the PL spectra of BZT-0.5BCT ceramics were found to be sensitive to polarization of the ferroelectric ceramics. Compared with the unpoled ceramics, the green emission increased about 42% and a new emission peak at 430 nm appeared for the poled ceramics. With excellent intrinsic ferroelectricity and an enhanced PL property, such material has potential to realize multifunctionality in a wide application range.


2012 ◽  
Vol 585 ◽  
pp. 219-223
Author(s):  
Rekha Kumari ◽  
N. Ahlawat ◽  
Ashish Agarwal ◽  
M. Sindhu ◽  
N.N. Ahlawat

Na0.5Bi0.5TiO3 (NBT) ceramics were synthesized by conventional solid state reaction method. Structural and dielectric properties of these ceramics were investigated. Crystalline phase of sintered ceramics was investigated by X-ray diffraction (XRD). The Rietveld refinement of powder X-ray diffraction revealed that the prepared ceramics exhibit the rhombohedral space group R3c. Dielectric properties of Na0.5Bi0. analyzer.5TiO3 (NBT) ceramics were studied at different temperatures in a wide frequency range using impedance


2015 ◽  
Vol 05 (01) ◽  
pp. 1550002 ◽  
Author(s):  
P. Sateesh ◽  
J. Omprakash ◽  
G. S. Kumar ◽  
G. Prasad

Ceramic samples of Barium Zirconium Titanate ( BaZr x Ti 1-x O 3 ( BZT )) were synthesized by conventional solid-state reaction method with different concentrations of x(= 0.05 ( BZT1 ), 0.10 (BZT2), 0.15 (BZT3), 0.20 (BZT4), 0.25 (BZT5), 0.30 (BZT6)). Phase confirmation of the samples was done by X-ray diffraction (XRD) technique. All the compositions are in cubic structure. XRD pattern was recorded for samples sintered at different sintering temperatures. Lattice parameters increased with addition of Zr +4. Doping with Zr +4 into Barium titanate resulted in interesting changes of electrical properties (dielectric, impedance and ferroelectiricity). The strong influence of Zr doping on the phase transition characteristics of the BZT ceramics was studied from the dielectric response of the samples. Diffusivity of phase transition of the BZT ceramic samples increase with Zr +4 concentration, indicating changes from normal to diffuse transition to relaxor phase transition behavior. Impedance spectroscopy reveals the presence of temperature-dependent grain, grain boundary effects. Polarization–Electricfield (PE) loop measurements are also done on the samples.


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