scholarly journals Electrical properties of KTa0.65Nb0.35O3 lead-free ceramics

2020 ◽  
Vol 14 (4) ◽  
pp. 372-377
Author(s):  
Felicia Gheorghiu ◽  
Mihai Asandulesa ◽  
Lavinia Curecheriu
Keyword(s):  
Solid State Reaction Method ◽  
Lead Free ◽  
Cubic Phase ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Suitable Candidate ◽  
X Ray ◽  
Tunable Capacitors ◽  
High Tunability ◽  
Lead Free Ceramics

In the present study, lead-free KTa0.65Nb0.35O3 ceramics were prepared by solid state reaction method using successive calcination steps in order to ensure the complete reaction of the system. The X-ray diffraction analyses of the prepared ceramics have shown the formation of a perovskite structure without any secondary phases. The increase of sintering temperature from 1150 to 1200?C leads to a better densification and decreasing of the Curie temperature (associated with tetragonal-cubic phase transition) closer to the room temperature, i.e. to 290K. The ceramics sintered at 1200?C exhibits a high tunability (n = 1.6) and a reduced hysteretic behaviour. Due to its moderate permittivity, low losses and field dependence permittivity, the KTa0.65Nb0.35O3 ceramics is suitable candidate for application as tunable capacitors.

Structure and Dielectric Properties of Bi0.5K0.5TiO3-SrTiO3 Lead-Free Ceramics

2011 ◽  
Vol 695 ◽  
pp. 166-169
Author(s):  
Anucha Ruangphanit ◽  
Prapapim Phetnoi ◽  
Surasak Niemcharoen ◽  
Rangson Muanghlua
Keyword(s):  
Single Phase ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Tetragonal Symmetry ◽  
Dielectric Study ◽  
Relaxor Behavior ◽  
X Ray Diffraction ◽  
Promising Candidate ◽  
X Ray ◽  
Lead Free Ceramics

Bismuth potassium titanate – strontium titanate (1-x)Bi0.5K0.5TiO3-(x)SrTiO3 (BKT-ST) lead-free ceramics when x = 0-0.20 were synthesized by the solid state reaction method with normal sintering. The ferroelectric phase transition was studied by X-ray diffraction (XRD). All compositions showed a single phase perovskite structure with tetragonal symmetry at room temperature and the phase structure transformed from ferroelectric tetragonal – paraelectric cubic in the range of x ³ 0.10 . Dielectric study revealed that the dielectric relaxor behavior was induced with increasing ST and transition temperature (Tm@εr max) of ST-doped BKT had a tendency to decrease with increasing ST. The Bi0.5K0.5TiO3 – SrTiO3 system was expected to be a new and promising candidate for lead-free capacitors.

scholarly journals Dielectric and Raman studies of Ba0.06(Na1/2Bi1/2)0.94TiO3–NaNbO3 ceramics

2016 ◽  
Vol 34 (2) ◽  
pp. 437-445 ◽  
Author(s):  
Sumit K. Roy ◽  
S. Chaudhuri ◽  
R.K. Kotnala ◽  
D.K. Singh ◽  
B.P. Singh ◽  
...  
Keyword(s):  
Single Phase ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Orthorhombic Symmetry ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
New Phase ◽  
Diffusivity Parameter

AbstractIn this work the X-ray diffraction, scanning electron microscopy, Raman and dielectric studies of lead free perovskite (1 – x)Ba0.06(Na1/2Bi1/2)0.94TiO3–xNaNbO3 (0 ⩽ x ⩽ 1.0) ceramics, prepared using a standard solid state reaction method, were investigated. X-ray diffraction studies of all the ceramics suggested the formation of single phase with crystal structure transforming from rhombohedral-tetragonal to orthorhombic symmetry with the increase in NaNbO3 content. Raman spectra also confirmed the formation of solid solution without any new phase. Dielectric studies showed that the phase transition is of diffusive character and diffusivity parameter decreases with increasing NaNbO3 content. The compositional fluctuation was considered to be the main cause of diffusivity.

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
Keyword(s):  
Lead Free ◽  
Ferroelectric Ceramics ◽  
Reaction Sintering ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Porosity Level ◽  
X Ray ◽  
Ceramic Samples ◽  
Lead Free Ceramics ◽  
Sintering Method

(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.

Electrical Properties of Modified BNT Based Lead-Free Ceramics

2016 ◽  
Vol 872 ◽  
pp. 87-91
Author(s):  
Supalak Manotham ◽  
Tawee Tunkasiri ◽  
Pharatree Jaita ◽  
Pichitchai Butnoi ◽  
Denis Russell Sweatman ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Free Ceramics

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.

scholarly journals Effect of Sol-Gel Synthesized BiFeO3 Nanoparticle Addition in YBa2Cu3O7–δ (Y123) Superconductor Synthesized by Standard Solid State Reaction Method

2019 ◽  
Vol 290 ◽  
pp. 245-251
Author(s):  
Abdalla Bahboh ◽  
Abdul Halim Shaari ◽  
Hussein Baqiah ◽  
Soo Kien Chen ◽  
Mohd Mustafa Awang Kechik ◽  
...  
Keyword(s):  
Sol Gel ◽  
Solid State Reaction Method ◽  
Superconducting Transition ◽  
Secondary Phases ◽  
Superconducting Properties ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Scanning Electron Micrograph ◽  
X Ray ◽  
Pure Ybco

The effects of the multiforric BiFO3 nanoparticles addition on the structure and superconducting properties of YBa2Cu3O7–δ (Y123) with different concentrations were systematically investigated using X-ray diffraction (XRD), field emission scanning electron micrograph (FESEM), EDX and four point probe measurement. It was found that the added samples were predominant by Y-123 phase beside small amount of Y-211 and unreacted BiFeO3 secondary phases. Samples with less (wt.%) BFO added YBCO precursor powder preserved the orthorhombic structure similar to the pure YBCO, while samples with higher wt% addition show orthorhombic-to-tetragonal transition tendency. The samples became more porous and their grain size slightly decreased with addition of BiFeO3. The addition of nanoBiFeO3 disturbed the grain growth of Y123, thus resulting in the degradation of superconducting properties of the samples. The superconducting transition temperature (Tc onset) of samples decreased from 92 K for x=0.0 to 44 K for x=10.0 wt. %, which could be attributable to oxygen vacancy disorder.

scholarly journals Effect of Sr-substitution on the structural and magnetoelectric properties of Ni-Zn ferrites

2020 ◽  
Vol 26 (2) ◽  
pp. 1-20
Author(s):  
SC Mazumdar ◽  
AT Trina ◽  
F Alam ◽  
MJ Miah ◽  
MNI Khan
Keyword(s):  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Solid State Reaction Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
Microstructural Investigation ◽  
Xrd Pattern ◽  
X Ray ◽  
Soft Ferrites

Spinel type polycrystalline Ni0.6-xZn0.4SrxFe2O4 (x = 0.0, 0.05, 0.10, 0.15 and 0.20) ferrites are synthesized by solid state reaction method. X-ray diffraction (XRD) pattern reveals the formation of spinel structure with two secondary phases Sr2FeO4 and SrFe12O19 for higher concentration of Sr (0.15 and 0.20). An increase in lattice constant is observed with the increase of Sr content in the lattice. The density of the samples is found to decrease whereas porosity increases with the substitution of Sr2+ ions. Microstructural investigation shows that the grain size increases with the increase of Sr content. Magnetic hysteresis is investigated at room temperature. All the samples exhibit lower coercivity values indicating that the materials belong to the class of soft ferrites. The saturation magnetization is found to decrease with Sr content which is attributed to Néel’s two sub-lattice model of ferrites. The real permeability of the samples remains almost constant up to a certain frequency and then falls rapidly. Improved dielectric constant is observed in the Sr2+ substituted samples. The electrical conduction in these ferrites is explained on the basis of hopping mechanism between the Fe2+ and Fe3+ ions. Bangladesh Journal of Physics, 26(2), 1-20, December 2019

scholarly journals Structure and Conductivity Studies of Scandia and Alumina Doped Zirconia Thin Films

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 317 ◽  
Author(s):  
Mantas Sriubas ◽  
Nursultan Kainbayev ◽  
Darius Virbukas ◽  
Kristina Bočkutė ◽  
Živilė Rutkūnienė ◽  
...  
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Size Dependence ◽  
Cubic Phase ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Impedance Measurements ◽  
Raman Analysis ◽  
X Ray ◽  
Co Doped

In this work, scandia-doped zirconia (ScSZ) and scandia–alumina co-doped zirconia (ScSZAl) thin films were prepared by electron beam vapor deposition. X-ray diffraction (XRD) results indicated a presence of ZrO2 cubic phase structure, yet Raman analysis revealed the existence of secondary tetragonal and rhombohedral phases. Thus, XRD measurements were supported by Raman spectroscopy in order to comprehensively analyze the structure of formed ScSZ and ScSZAl thin films. It was also found that Al dopant slows down the formation of the cubic phase. The impedance measurements affirmed the correlation of the amount of secondary phases with the conductivity results and nonlinear crystallite size dependence.

Powder X-ray diffraction data of new bismuth yttrium gadolinium oxides

2008 ◽  
Vol 23 (3) ◽  
pp. 255-258
Author(s):  
M. Alizadeh ◽  
K. Ahmadi ◽  
A. Maghsudipour ◽  
F. Moztarzadeh
Keyword(s):  
Diffraction Data ◽  
Solid State Reaction Method ◽  
Cubic Phase ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Good Agreement

X-ray powder diffraction data for five new bismuth yttrium gadolinium oxide compounds synthesized by solid state reaction method are reported. The unit cell dimensions were determined from X-ray diffraction methods, using CuKα radiation, and evaluated by indexing programs. The cubic phase was the sole crystalline phase detected by X-ray diffraction analysis in Bi0.88Y0.06Gd0.06O1.5, Bi0.88Y0.08Gd0.04O1.5, Bi0.82Y0.09Gd0.09O1.5, Bi0.82Y0.12Gd0.06O1.5, and Bi0.82Y0.06Gd0.12O1.5 samples with lattice constants of a=5.5371(1) Å, a=5.5368(1) Å, a=5.5303(2) Å, a=5.53487(8) Å, and a=5.5279(1) Å, respectively. The results are in good agreement with those reported for bismuth yttrium oxide (Bi0.75Y0.25)O1.5 (PDF 01-084-1450).

STRUCTURE AND PIEZOELECTRIC PROPERTIES OF (Bi0.5Na0.5)1-x-y-zBax(Bi0.5Li0.5)ySrzTiO3 LEAD-FREE CERAMICS

2010 ◽  
Vol 03 (01) ◽  
pp. 49-53 ◽  
Author(s):  
DUNMIN LIN ◽  
K. W. KWOK
Keyword(s):  
Crystal Structure ◽  
Remanent Polarization ◽  
Piezoelectric Properties ◽  
Lead Free ◽  
X Ray Diffraction ◽  
Pure Perovskite Structure ◽  
X Ray ◽  
Lead Free Ceramics ◽  
Diffraction Patterns ◽  
Sintering Method

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 .

Sign in / Sign up

Export Citation Format

Share Document