Structural and Electrical Properties of Ca2+ Substituted Pb[(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02]0,96 P0,04 O3 Ceramics

2014 ◽  
Vol 87 ◽  
pp. 18-23
Author(s):  
Louanes Hamzioui ◽  
Fares Kahoul ◽  
Ahmed Boutarfaia
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Rhombohedral Phase ◽  
Dissipation Factor ◽  
Sintering Behavior ◽  
Practical Applications ◽  
Low Dissipation ◽  
High Dielectric

Pb1-xCax[(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02]0,96P0,04O3(x = 0,00, 0.02, 0.04, 0.06) ceramics were prepared using the conventional mixed-oxide route. The resultant samples were sintered at different temperatures and subsequently characterized in terms of both microstructure and dielectric properties to study the effects of sintering behavior. X-ray diffraction analysis reveals that all specimens are a pure perovskite phase without pyrochlore phase and exhibits a phase transition from a rhombohedral phase to the coexistence of rhombohedral and tetragonal phases with an increase of sintering temperature. The grain size first increases up tox= 0.02 and then decreases. Comparing with the undoped ceramics, the dielectric properties of the Ca-doped PZT–PCTP specimens are significantly improved. The results show that the ceramics sintered at 1180°C have optimum electrical properties for x= 0.02: a high dielectric constant (εr= 16800) at Tc, a low dissipation factor (tanδ = 0.009) and a low resistivity (ρ= 0.09 ×10+4) (Ω.cm) at 1 kHz, which indicates that the PZT–CCTP ceramics are promising for lead practical applications.

Sintering behavior and dielectric properties of Bi3+-substituted Nd(Zn0.5Ti0.5)O3 microwave ceramics

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550233 ◽  
Author(s):  
Mingzhe Hu ◽  
Zhao Ding ◽  
Gang Xiong ◽  
Denghui Ji ◽  
Kesheng Zhang
Keyword(s):  
Dielectric Properties ◽  
Volume Fraction ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Microwave Ceramics ◽  
Microwave Dielectric ◽  
Bi Doping ◽  
Sintering Conditions

The sintering behavior and dielectric properties of Bi[Formula: see text]-substituted Nd(Zn[Formula: see text]Ti[Formula: see text]O3 (abbreviated as NZT) microwave ceramics (Nd[Formula: see text]Bi[Formula: see text])(Zn[Formula: see text]Ti[Formula: see text])O3 [Formula: see text] (abbreviated as NBZT) are investigated. XRD results reveal the formation of single perovskite solid solutions for [Formula: see text] samples. For [Formula: see text] samples, pyrochlore phase begins to segregate from the perovskite phase and its volume fraction increases with [Formula: see text]. B-site Zn[Formula: see text]/Ti[Formula: see text] 1:1 long range order (LRO) is detected by Raman Spectroscopy. The degree of LRO varies as a function of sintering conditions and chemical composition. The microwave dielectric properties of the composition are measured. By substituting Bi[Formula: see text] for Nd[Formula: see text], the temperature coefficient of resonant frequency [Formula: see text] tunes toward zero, however, the microwave quality factor, [Formula: see text] deteriorates. For [Formula: see text], [Formula: see text] reaches a minimum value of [Formula: see text] with relative permittivity of [Formula: see text] and [Formula: see text], respectively. The effect of Bi-doping on the [Formula: see text] value is discussed.

scholarly journals LTCC and Bulk Zn4B6O13–Zn2SiO4 Composites for Submillimeter Wave Applications

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1014
Author(s):  
Dorota Szwagierczak ◽  
Beata Synkiewicz-Musialska ◽  
Jan Kulawik ◽  
Norbert Pałka
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dissipation Factor ◽  
Submillimeter Wave ◽  
Sintering Behavior ◽  
High Frequencies ◽  
Low Dielectric ◽  
Low Dissipation ◽  
Temperature Dependences ◽  
Very High Frequencies

New zinc metaborate Zn4B6O13–willemite Zn2SiO4 composites were investigated as promising materials for LTCC (low temperature cofired ceramics) substrates of microelectronic circuits for submillimeter wave applications. Composites were prepared as bulk ceramics and LTCC multilayer structures with cofired conductive thick films. The phase composition, crystal structure, microstructure, sintering behavior, and dielectric properties were studied as a function of willemite content (0, 10, 13, 15, 20, 40, 50, 60, 100 wt %). The dielectric properties characterization performed by THz time domain spectroscopy proved the applicability of the composites at very high frequencies. For the 87% Zn4B6O13–13% Zn2SiO4 composite, the best characteristics were obtained, which are suitable for LTCC submillimeter wave applications. These were a low sintering temperature of 930 °C, compatibility with Ag-based conductors, a low dielectric constant (5.8 at 0.15–1.1 THz), a low dissipation factor (0.006 at 1 THz), and weak frequency and temperature dependences of dielectric constant.

scholarly journals Synthesis of Polymer-based ZnO/TiO2 NCs Flexible Sheets as High Dielectric Materials

2021 ◽  
Author(s):  
N. Kanwal ◽  
S. Pervaiz ◽  
A. Rasheed ◽  
M. Saleem ◽  
Ijaz Ahmad Khan
Keyword(s):  
Dielectric Permittivity ◽  
Complex Impedance ◽  
Microscopic Analysis ◽  
Dielectric Materials ◽  
Dissipation Factor ◽  
X Rays ◽  
Energy Storage Devices ◽  
Electron Microscopic ◽  
Low Dissipation ◽  
High Dielectric

Abstract Polymer-based ZnO/TiO2 NCs flexible sheets with high dielectric permittivity and low loss factor have numerous applications in light emitting and energy storage devices. In this work, polymer-based ZnO/TiO2 NCs are synthesized by co-precipitation technique. The development of various diffraction planes (X-rays diffraction analysis) related to TiO2 and ZnO phases confirms the synthesis of polycrystalline polymer-based ZnO/TiO2 NCs. The crystallinity of various phases is associated with increasing ZnO nanofillers. The surface morphology (scanning electron microscopic analysis) comprising of nanoparticles of different shapes is associated with increasing amount of nanofillers. The EDX analysis confirms the presence of Zn, O and Ti in the synthesized polymer-based ZnO/TiO2 NCs. Dielectric measurements demonstrating the sharp increase in dielectric permittivity with relatively low dissipation factor of synthesized polymer-based ZnO/TiO2 NCs are associated with increasing amount of ZnO nanofillers. The static value of dielectric constant (e’) at low frequency (100 Hz) is found to be 14.56 for sample having 10% ZnO nanofillers that is 2.11 times greater than pure PVDF and it shows relatively low value of dissipation factor. The observed σac of synthesized polymer-based ZnO/TiO2 NCs at 3.0×105 Hz and 1.0×106 Hz are ranged from 3.75-9.79 and 15.61-42.72 mS/m respectively. The decreasing complex impedance and increasing electric modulus further confirm that the synthesized polymer-based ZnO/TiO2 NCs flexible sheets are the promising candidate for better capacitive performance showing high strength and flexibility.

Preparation of BaTiO3/PMMA Dielectric Films by Screen Printing

2015 ◽  
Vol 748 ◽  
pp. 163-169
Author(s):  
Xin Zhou Wu ◽  
Zheng Chen ◽  
Teng Zhou ◽  
Shuang Shuang Shao ◽  
Mei Lan Xie ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Volume Fraction ◽  
Composite Films ◽  
Dielectric Films ◽  
Practical Applications ◽  
Low Dissipation ◽  
High K ◽  
High Dielectric ◽  
Surface Modified ◽  
Screen Printed

The high-k composite dielectric ink is prepared by dispersing the surface modified BaTiO3 in PMMA solution. The high quality BaTiO3-PMMA composite films are screen printed on ITO glasses. BaTiO3 nanoparticles are surface modified with a silane coupling agent (MPTMS) to improve their affinity for PMMA matrix. The dielectric constant, loss tangent, specific capacitance and transmittance of BaTiO3/PMMA nanocomposites are investigated as the function of volume fraction of BaTiO3. These composites, which possess both high dielectric constant and low dissipation factors and can be screen printed at ambient temperature and pressures, have very wide practical applications.

Sintering behavior and dielectric properties of pyrochlore Pb2FeWO6.5

1994 ◽  
Vol 9 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Chung-Hsin Lu ◽  
Nobuyasu Mizutani
Keyword(s):  
Dielectric Properties ◽  
Grain Growth ◽  
Hot Isostatic Pressing ◽  
Applied Pressure ◽  
Decomposition Temperature ◽  
Dielectric Constants ◽  
Sintering Behavior ◽  
Low Dielectric ◽  
Low Dissipation ◽  
Pyrochlore Type

Pyrochlore-type Pb2FeWO6.5 is difficult to be sintered without applied pressure at temperatures lower than its decomposition temperature. Through hot pressing or hot isostatic pressing processes, densification of specimens is greatly enhanced; moreover, grain growth during sintering is effectively suppressed. Densified Pb2FeWO6.5 exhibits paraelectric characteristic from −135°to −2 °C with low dielectric constants and low dissipation factors. The dielectric constants show rather weak dependence of temperature and frequency.

Ferroelectric thin films with complex composition of PNN–PZN–PMN–PZ–PT and excess NiO

2008 ◽  
Vol 23 (2) ◽  
pp. 536-542 ◽  
Author(s):  
Phoi Chin Goh ◽  
Kui Yao ◽  
Zhong Chen
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Oxide System ◽  
Ferroelectric Thin Films ◽  
Ionic Radii ◽  
Pt Complex ◽  
The Stability

Ferroelectric thin films of the 0.1Pb(Ni1/3Nb2/3)O3–0.35Pb(Zn1/3Nb2/3)O3–0.15Pb (Mg1/3Nb2/3)O3–0.1PbZrO3–0.3PbTiO3 (PNN–PZN–PMN–PZ–PT) complex oxide system were prepared on Pt/Ti/SiO2/Si substrates using a polymer-modified sol-gel method followed by a rapid thermal annealing (RTA) process. It was found that the addition of excess NiO is effective in stabilizing the perovskite phase while suppressing the pyrochlore phase. The crystalline structure and morphology of the films with different amounts of access NiO were studied with x-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The electrical properties, including dielectric, ferroelectric, and piezoelectric, showed a significant improvement with excess NiO. The film sample with 3 mol% of excess NiO exhibited optimized electrical properties. Different parameters, including tolerance factors on the basis of ionic radii, electronegativity differences between cations and anions, and oxygen bond valences, were applied to analyze the stability of the perovskite phase with different amount of excess NiO. Analysis results indicated that only the bond-valence theory could explain the effect of excess NiO on the stability of the perovskite phase under the assumption that the excess Ni2+ entered the A sites of the perovskite structure.

Impact of sintering temperatures on conduction behaviors of ZnO nanoparticles- and MnO-doped SnO2-based thick film varistors obtained by screen printing

2019 ◽  
Vol 33 (27) ◽  
pp. 1950336
Author(s):  
Rabab Sendi
Keyword(s):  
Electrical Properties ◽  
Thick Film ◽  
Zno Nanoparticles ◽  
Screen Printing ◽  
Sintering Temperature ◽  
Dissipation Factor ◽  
Breakdown Field ◽  
Zno Nanoparticle ◽  
Sintering Process ◽  
Low Dissipation

In this study, ZnO nanoparticles and MnO-doped SnO2-based thick film varistors (TFVs) were fabricated using screen printing technique. The sintering temperature had significant impact on the SZM-based TFVs, especially in terms of grain growth, even at a low sintering temperature of 1100[Formula: see text]C. The strong solid-state reaction during sintering may be attributed to the large surface area of the 20 nm ZnO nanoparticles that promoted strong surface reaction even at low sintering temperatures. Moreover, the X-ray diffraction lattice constant and full wave at half maximum data indicated that the sintering process also improved the grain crystallinity with the decrease in intrinsic compressive stress. The sintering temperatures also significantly influenced the electrical properties of the SZM-based TFVs with a significant decrease in the breakdown field from 360 V/mm (sample at 1100[Formula: see text]C) to 158 V/mm (sample at 1250[Formula: see text]C). The grain boundary resistance ([Formula: see text] also experienced a dramatic drop from 266.4 k[Formula: see text] (sample at 1100[Formula: see text]C) to 89.46 k[Formula: see text] (sample at 1250[Formula: see text]C). The sample sintered at 1200[Formula: see text]C exhibited superior electrical behaviors with a nonlinear exponent of 61 and leakage current of 115 [Formula: see text]A. Furthermore, it achieved high permittivity and low dissipation factor at the low frequency range. The conduction behaviors of [Formula: see text] ions with activation energy of approximately 0.6 eV was dominated by decreasing [Formula: see text] and [Formula: see text] defects (around 0.4 eV) with increasing sintering temperature. Therefore, the sintering process can be applied to control the conduction behaviors of SZM-based TFVs doped with ZnO nanoparticle powder and achieve improved structural and electrical properties with good nonlinear behaviors.

Dielectric Properties of Importance in Operations of Post-harvest of Sorghum

2017 ◽  
Vol 13 (4) ◽  
Author(s):  
Caciano P. Z. Noreña ◽  
Carlos E. Lescano-Anadón
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Loss Factor ◽  
Dissipation Factor ◽  
Post Harvest ◽  
Moisture Contents ◽  
And Storage

Abstract The knowledge of electrical properties and their relationship with moisture content is of great importance in operations of post-harvest and storage in grains. The dielectric properties of sorghum samples were studied at different moisture contents and temperatures (25 at 41 °C), at frequencies of 1 and 10 kHz. In order to measure changes in the capacitance and dissipation factor of the samples, the method of impedance bridge was used. Both the dielectric constant and the dielectric loss factor of the samples increased with increasing moisture content and temperature; however, they decreased with increasing frequency. Models were proposed to relate the dielectric properties to either the moisture (exponential and polynomial) or temperature (linear).

Effect of La2O3 on the Electrical Properties of WO3-Based Varistor Ceramics

2011 ◽  
Vol 480-481 ◽  
pp. 137-141
Author(s):  
Tian Guo Wang ◽  
Qun Qin ◽  
Wen Jun Zhang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Crystal Lattice ◽  
Breakdown Voltage ◽  
High Dielectric Constant ◽  
Electrical Characteristics ◽  
Electrical Behavior ◽  
High Dielectric

The nonlinear electrical behavior and dielectric properties of WO3-based ceramics with various La2O3 contents have been investigated. Breakdown voltages Eb of WO3 doped with La2O3 are lower than that of undoped WO3, indicating that the dopant can reduce the breakdown voltage. The dielectric constant of doped samples is higher than that of undoped samples, and the high dielectric constant makes them suitable as capacitor-varistor materials. The theory defects in the crystal lattice was introduced to explain the nonlinear electricial behavior of the La2O3-doped WO3 ceramics. In view of these electrical characteristics, the WO3 ceramic doped with La2O3 is a viable candidate for capacitor-varistor functional devices.

Dielectric Properties of Hot-Pressed of SiCN/A3S2 Nanocomposites

2007 ◽  
Vol 334-335 ◽  
pp. 697-700 ◽  
Author(s):  
Fa Luo ◽  
Dong Mei Zhu ◽  
San Tuan Zhao ◽  
Wan Cheng Zhou
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
Dissipation Factor ◽  
Saed Pattern ◽  
Pressing Method ◽  
The Real ◽  
X Band ◽  
Higher Temperature ◽  
High Dielectric

A series of nanocomposites, SiCN/A3S2 ceramics, were prepared by hot-pressing method. The nanometer SiCN powder is characterized of high dielectric dissipation. The dielectric properties of the SiCN/A3S2 nanocomposites were investigated. XRD and SEM were conducted to study the phases and microstructure of the nanocomposites. Compared with the pure A3S2 ceramic, the grain size in the nanocomposites is reduced due to the addition of nanometer SiCN powder. The relative densities of the nanocomposites are also lower than that of the pure A3S2 ceramic. Both the real and imaginary parts of the complex permittivity of nanocomposites in X band increase as the content of SCN powder in the samples rises obviously. When the contents of SiCN powder in samples are same, the real and imaginary parts of the samples vary with the sintering temperature. The tanδ of the nanocomposites reduces from 1.9 to 1.4 when sintering temperature increases from 1450OC to 1650 OC. SAED pattern reveals that structure of the SiCN in SiCN/ A3S2 sintered at higher temperatures tend to crystallize. The real, imaginary parts and dissipation factor of the nanocomposites sintered at higher temperature is lower than those sintered at 1450 °C.

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