scholarly journals Three-Phase Borate Solid Solution With Low Sintering Temperature, High Quality Factor, and Low Dielectric Constant: Experimental and DFT Study

2020 ◽  
Author(s):  
Rui Peng ◽  
Hua Su ◽  
Yuanxun Li ◽  
Yongcheng Lu ◽  
Liang Shi ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Solid State Reactions ◽  
Network Analyzer ◽  
First Principles Calculations ◽  
Characterization Methods ◽  
Low Dielectric ◽  
Microwave Dielectric ◽  
Three Phase ◽  
Electron Distributions

Abstract The sintering and microwave dielectric properties of a ceramic material based on Mg2+ substituted Zn3B2O6 have been widely studied using first principles calculations and experimental solid-state reactions. Characterization methods include the Network Analyzer, X-ray, Raman diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and differential-thermal & thermo-mechanical analyzer. The increasing amount of Mg2+ results in the appearance of Mg2B2O5 and ZnO, and the mutual substitution (Mg2+ and Zn2+) phenomenon has emerged in Zn3B2O6 and Mg2B2O5. The mechanisms have been explained with the help of DFT calculations. The bond parameters and electron distributions of the ZnO4 tetrahedron and the MgO6 octahedron have been modified due to substitution. The sintering, substitution, and phase formation properties have been analyzed quantitatively through the energy parameters. The best dielectric properties were obtained for x=0.20 sintered at 950℃, εr=6.47, Q×f=89,600GHz (15.2GHz), τf=-48.6ppm/℃, relative density=96.7%. The substitution of Mg2+ to Zn2+ is a feasible method to improve the microwave dielectric properties of the Zn3B2O6 ceramic.

scholarly journals Structural, optical and microwave dielectric properties of Ba(Ti1−xSnx)4O9, 0 ≤ x ≤ 0.7 ceramics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Asad Ali ◽  
Sarir Uddin ◽  
Madan Lal ◽  
Abid Zaman ◽  
Zafar Iqbal ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Low Dielectric ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Red Color ◽  
High Dielectric ◽  
Quality Factor Q

AbstractSn-doped BaTi4O9 (BT4) dielectric ceramics were prepared by a mixed oxide route. Preliminary X-ray diffraction (XRD) structural study shows that the ceramic samples have orthorhombic symmetry with space group (Pnmm). Scanning electron microscopy (SEM) shows that the grain size of the samples decreases with an increase in Sn4+ content. The presence of the metal oxide efficient group was revealed by Fourier transform infrared (FTIR) spectroscopy. The photoluminescence spectra of the ceramic samples reported red color ~ 603, 604, 606.5 and 605 nm with excitation energy ~ 2.06, 2.05, 2.04 and 2.05 eV for Sn4+ content with x = 0.0, 0.3, 0.5, and 0.7, respectively. The microwave dielectric properties of these ceramic samples were investigated by an impedance analyzer. The excellent microwave dielectric properties i.e. high dielectric constant (εr = 57.29), high-quality factor (Qf = 11,852), or low-dielectric loss (3.007) has been observed.

scholarly journals Phase, microstructure and microwave dielectric properties of Mg0:95Ni0:05Ti0:98Zr0:02O3 ceramics

2015 ◽  
Vol 33 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Abdul Manan ◽  
Dil Nawaz Khan ◽  
Atta Ullah ◽  
Arbab Safeer Ahmad
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Secondary Phase ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Scanning Electron

AbstractMg0:95Ni0:05Ti0:98Zr0:02O3 ceramics was prepared via conventional solid-state mixed-oxide route. The phase, microstructure and microwave dielectric properties of the sintered samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and a vector network analyzer. The microstructure comprised of circular and elongated plate-like grains. The semi quantitative analysis (EDS) of the circular and elongated grains revealed the existence of Mg0:95Ni0:05T2O5 as a secondary phase along with the parent Mg0:95Ni0:05Ti0:98Zr0:02O3 phase, which was consistent with the XRD findings. In the present study, εr ~17.1, Qufo~195855 ± 2550 GHz and τf ~ -46 ppm/K was achieved for the synthesized Mg0:95Ni0:05Ti0:98Zr0:02O3 ceramics sintered at 1325 °C for 4 h.

Ordering and microwave dielectric properties of Ba(Ni1/3Nb2/3)O3 ceramics

1997 ◽  
Vol 12 (2) ◽  
pp. 518-525 ◽  
Author(s):  
In-Tae Kim ◽  
Yoon-Ho Kim ◽  
Su Jin Chung
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Nucleation And Growth ◽  
Annealing Process ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Transmission Electron ◽  
Rich Liquid

Ordering and microwave dielectric properties of Ba(Ni1/3Nb2/3)O3 have been investigated using x-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, and a network analyzer. Samples sintered at 1400 °C for 2 h were disordered and showed the presence of Nb-rich liquid phase at grain boundary junctions. Degree of ordering increased with following annealing at 1300 °C. Growth of the ordered region during the annealing process was discussed in terms of nucleation and growth. A long-range order parameter was calculated using structure factor. Measurements of microwave dielectric properties showed that permittivity and temperature coefficient of resonant frequency decreased with ordering, and quality factor increased with ordering. The correlation between microwave dielectric properties and ordering was discussed in terms of covalency of bonding, inhomogeneous charge distribution, and defects concentration.

Microwave dielectric properties of Ba4LaTi0.3Sn0.7Nb3O15 ceramic

2014 ◽  
Vol 28 (15) ◽  
pp. 1450092 ◽  
Author(s):  
Abdul Manan ◽  
Imtiaz Hussain
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Least Squares Method ◽  
Microwave Dielectric Properties ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Microstructural Investigation ◽  
Microwave Frequencies ◽  
Microwave Dielectric ◽  
Lcr Meter

Ba 4 LaTi 0.3 Sn 0.7 O 15 ceramic was prepared through conventional solid state mix oxide route followed by characterization using X-ray diffraction (XRD) and scanning electron microscope (SEM) for phase and microstructural investigation. The dielectric properties at low and microwave frequencies were measured using LCR meter and vector network analyzer. XRD results revealed single phase ceramics and the microstructure was comprised of compact grains with size ranging from 4–12 μm. The lattice parameters refined by the least squares method were a = b = 5.7680(2) Å, c = 11.7491(6) Å, V = 337.81 Å3 and Z = 1. Optimum properties i.e., εr~44.6, Qufo~15, 500 GHz and τf~2.05 ppm /° C were achieved for Ba 4 LaTi 0.3 Sn 0.7 Nb 3 O 15 ceramic sintered at 1475°C for 4 h.

First-principles calculations of graphene-based polyaniline nano-hybrids for insight of electromagnetic properties and electronic structures

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73915-73923 ◽  
Author(s):  
Yuping Duan ◽  
Jin Liu ◽  
Yahong Zhang ◽  
Tongmin Wang
Keyword(s):  
Dielectric Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Microwave Dielectric Properties ◽  
First Principles Calculation ◽  
Electromagnetic Properties ◽  
First Principles Calculations ◽  
Microwave Dielectric

The microwave dielectric properties of graphene-based polyaniline hybrids are studied based on experiments and first-principles calculation.

Effects of Ti4+ Substitution on Microstructure and Microwave Dielectric Properties of ZnNb2(1-x)TixO(6-3x) Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 19-22
Author(s):  
Ying Chun Zhang ◽  
Zhen Xing Yue ◽  
Jin Wang ◽  
Zhi Lun Gui ◽  
Long Tu Li
Keyword(s):  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Microwave Dielectric Properties ◽  
Network Analyzer ◽  
Quality Factors ◽  
Microwave Frequencies ◽  
Microwave Dielectric ◽  
Dielectric Ceramics ◽  
Ti Content

The microstructure and microwave dielectric properties of dielectric ceramics comprised of ZnNb2(1-x)TixO(6-3x) (x = 0 ~ 1) were investigated systematically using X-ray powder diffraction, SEM and a network analyzer in this study. The results showed that four phases were observed in this system. The dielectric properties at microwave frequencies exhibit a significant dependence on the composition and crystal structure of the ceramics. The dielectric constant ( er) of ZnNb2(1-x)TixO(6-3x)ceramics increases with increasing Ti content and the quality factors (Q ×f) significantly decreased. However, the temperature coefficient of resonant frequency ( t f ) changes from –59.08 ppm/oC at x = 0 to + 25.1 ppm/oC at x = 1, and a zero temperature coefficient of resonant frequency ( t f ) for this ceramics system was obtained at x = 0.84.

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