scholarly journals Effect of Pressure on the Synthesis of Compound Ba0.7Ca0.3TiO3 on the Dielectric Constant

2020 ◽  
Vol 22 (1) ◽  
pp. 1
Author(s):  
Windarjoto Windarjoto ◽  
S Poniman ◽  
Made Hendra Hadinata
Keyword(s):  
Dielectric Constant ◽  
Ceramic Materials ◽  
Ferroelectric Ceramic ◽  
Ferroelectric Materials ◽  
Advanced Technology ◽  
Frequency Range ◽  
Solid Reaction ◽  
Reaction Method ◽  
Effect Of Pressure ◽  
Lcr Meter

Piezoelectric and ferroelectric ceramic materials are widely used for advanced technology. Barium Titanat is one of the ferroelectric materials that are still widely studied today. In this research, Ba0,7Ca0,3TiO3 was synthesized. The compound was synthesized by the solid reaction method with variations in pressure during the sample compacting process include 10, 20, and 30 kN. Samples in the form of solids (pellets) were calcined at 800 °C and sintered at 1000 °C for 4 hours respectively. The synthesized product was characterized by an LCR meter. The characterization results in the frequency range of 100-200000 Hz show that the pressure affects of the parameters value of the dielectric constant, especially at frequencies 100-10000 Hz. In that frequency range the dielectric constant decreases very sharply, then above 100 kHz the dielectric constant is almost unchanged with increasing frequency.

Preparation and Investigation on Properties of the MgTiO3-CaTiO3 Microwave Ceramic Materials

2014 ◽  
Vol 997 ◽  
pp. 419-423 ◽  
Author(s):  
Li Dong ◽  
Gui Xia Dong ◽  
Yuan Yuan Li ◽  
Xi Zhang
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Volume Density ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Solid Reaction ◽  
Reaction Method ◽  
Microwave Ceramic ◽  
Sintering Method

The MgTiO3 and CaTiO3 powders were synthesized by solid reaction method, and MgTiO3-CaTiO3 ceramic was prepared using pressureless sintering method. The experiment prepared MgTiO3-CaTiO3 ceramics with high compactness and stable permittivity by the way of changing the mole ratio of MgTiO3 and CaTiO3 to investigate the effect of CaTiO3 on the performances of MgTiO3-CaTiO3 ceramics. The results show that Mg2TiO4 formed as second phase during sintering. Volume density and dielectric constant of MgTiO3-CaTiO3 ceramics with 10%mol CaTiO3 reach maximum of 3.612g/cm3 and 17.8, respectively, under 1460°C sintering temperature. And for the MgTiO3-CaTiO3 ceramics with 5%mol CaTiO3 the maximum values which are 3.5g/cm3 and 16.6, respectively, appear under 1510°C sintering temperature.

scholarly journals Estimation of S-parameters and dielectric permittivity of quartz ceramics samples in millimeter waveband

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 65-71
Author(s):  
N. A. Pevneva ◽  
D. A. Kondrashov ◽  
A. L. Gurskii ◽  
A. V. Gusinsky
Keyword(s):  
Dielectric Constant ◽  
Dielectric Permittivity ◽  
Ceramic Materials ◽  
Reflection And Transmission Coefficients ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Higher Order Modes ◽  
S Parameters ◽  
The Fourier Transform

A modified Nicholson – Ross – Weir method was used to determine complex parameters and dielectric permittivity of ceramic materials in the range 78.33–118.1 GHz. The measuring equipment is a meter of complex reflection and transmission coefficients, a waveguide measuring canal with a special measuring cell, consisting of two irregular waveguides and a waveguide chamber between them, which provides insignificant influence of higher-order modes. The dependences of the amplitude and phase of the reflection and transmission coefficients on frequency were obtained experimentally for fluoroplastic and three ceramic samples in the frequency range 78.33–118.1 GHz. The obtained S-parameters are processed according to an algorithm that includes their averaging based on the Fourier transform in order to obtain the values of the dielectric permittivity. Fluoroplastic was used as a reference material with a known dielectric constant. The dielectric constant of fluoroplastic has a stable value of 2.1 in the above mentioned frequency range. The dielectric constant of sample No. 1 varies from 3.6 to 2.5 at the boundaries of the range, sample No. 2 – from 3.7 to 2.1, sample No. 3 – from 2.9 to 1.5. The experimental data are in satisfactory agreement with the literature data for other frequencies taking into account the limits set by the measurement uncertainty.

scholarly journals Structure and electric properties of cerium substituted SrBi1.8Ce0.2Nb2O9 and SrBi1.8Ce0.2Ta2O9 ceramics

2016 ◽  
Vol 10 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Mohamed Afqir ◽  
Amina Tachafine ◽  
Didier Fasquelle ◽  
Mohamed Elaatmani ◽  
Jean-Claude Carru ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Room Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Lcr Meter ◽  
Curie Temperature Tc

SrBi1.8Ce0.2Nb2O9 (SBCN) and SrBi1.8Ce0.2Ta2O9 (SBCT) powders were prepared via solid-state reaction method. X-ray diffraction analysis reveals that the SBCN and SBCT powders have the single phase orthorhom-bic Aurivillius structure at room temperature. The contribution of Raman scattering and FTIR spectroscopy of these samples were relatively smooth and resemble each other. The calcined powders were uniaxially pressed and sintered at 1250?C for 8 h to obtaine dense ceramics. Dielectric constant, loss tangent and AC conductivity of the sintered Ce-doped SrBi2Nb2O9 and SrBi2Ta2O9 ceramics were measured by LCR meter. The Ce-doped SBN (SBCN) ceramics have a higher Curie temperature (TC) and dielectric constant at TC (380?C and ?? ~3510) compared to the Ce-doped SBT (SBCT) ceramics (330?C and ?? ~115) when measured at 100Hz. However, the Ce-doped SBT (SBCT) ceramics have lower conductivity and dielectric loss.

Application of a Computational Micro-Electro-Mechanical Model for the Prediction of Self-Heating of Ferroelectric Ceramic Materials

Aerospace ◽  
2003 ◽  
Author(s):  
Lisa Mauck Weiland
Keyword(s):  
Ceramic Materials ◽  
Ferroelectric Ceramic ◽  
Ferroelectric Materials ◽  
Material Behavior ◽  
Combined Loading ◽  
Self Heating ◽  
Heating Effects ◽  
Rate Effects ◽  
Polycrystalline Model ◽  
Insight Into

Application of ferroelectric materials in devices subject to high fields and a range of drive frequencies is becoming increasingly common. As a result, self-heating of these devices is of concern. An energy based polycrystalline model including thermal and rate effects has been developed. The model has been developed from the thermodynamics of piezoelectrics, and includes elastic, dielectric, and piezoelectric anisotropy. It captures ferroelectric and ferroelastic switching under combined loading. In the current work the model is expanded to include self-heating effects. Model results are compared to experimental data. Results from the model give insight into material behavior.

scholarly journals PENGUKURAN NILAI DIELEKTRIK MATERIAL CALCIUM COPPER TITANAT ( CaCu3Ti4O12) MENGGUNAKAN SPEKTROSKOPI IMPEDANSI TERKOMPUTERISASI

2017 ◽  
Vol 6 (1) ◽  
pp. 26
Author(s):  
Widodo Budi Kurniawan
Keyword(s):  
Dielectric Constant ◽  
Impedance Spectroscopy ◽  
Ceramic Materials ◽  
Complex Dielectric Constant ◽  
Frequency Range ◽  
Frequency Dependent ◽  
Calcium Copper Titanate ◽  
Ccto Sample

Telah dilakukan pengukuran tetapan dielektrik kompleks dan besarnya impedansi kapasitor pada material keramik Calcium Copper Titanate dengan struktur material CaCu3Ti4O12 (CCTO) dengan kemurnian 99 % menggunakan metode spektroskopi impedansi terkomputerisasi dalam rentang frekuensi 5 kHz – 120 kHz. Tetapan dielektrik maksimum terukur pada sampel yang disintering dengan suhu 7000C yaitu 745 pada frekuensi 5 kHz dan besarnya impedansi kapasitor maksimum terjadi pada sampel CCTO non sintering yaitu 150434 Ω. Hasil penelitian menunjukkan adanya pengaruh frekuensi terhadap tetapan dielektrik kompleks dan impedansi kapasitor dari material yang diteliti. Kata kunci : spektroskopi impedansi, CaCu3Ti4O12, tetapan dielektrik kompleks dan impedansi kapasitor.   MEASUREMENT OF THE DIELECTRIC CONSTANT CALCIUM COPPER TITANATE (CaCu3Ti4O12) MATERIALS USING COMPUTERIZED IMPEDANCE SPECTROSCOPY  ABSTRACT The measurement of the complex dielectric constant and the magnitude of the capacitor impedances of the ceramic materials Calcium Copper Titanate CaCu3Ti4O12 (CCTO) with purity of 99% has been done by using the method of computerized impedance spectroscopy in the frequency range 5 kHz - 120 kHz. The highest dielectric constant of the material was found to be 745 at 5 kHz in the sample sintered 7000C and the highest impedance of capacitor occured in CCTO sample non sintered that is 150434Ω. The results showed that complex dielectric constant and impedance of the capacitor of the material under study was frequency dependent. Keywords : impedance spectroscopy, CaCu3Ti4O12,complex dielectric constant and impedance of capacitor

EFFECT OF TWO-DIMENSIONAL MECHANICAL STRESS ON THE DIELECTRIC PROPERTIES OF POLED CERAMIC BARIUM TITANATE AND LEAD ZIRCONATE TITANATE

1961 ◽  
Vol 39 (5) ◽  
pp. 741-753 ◽  
Author(s):  
R. F. Brown
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Barium Titanate ◽  
Lead Zirconate Titanate ◽  
Ceramic Materials ◽  
Ferroelectric Ceramic ◽  
Lead Zirconate ◽  
Dielectric Behavior ◽  
Two Dimensional

Studies have been made of the dielectric behavior of several ferroelectric ceramic materials when a two-dimensional stress was applied normal to the axis of polarization. It has been shown that the dielectric constant decreases and the dielectric loss increases with increasing stress, part of the change being irreversible and part reversible. Upon application of stress to a sample, the dielectric constant did not change instantaneously but appeared to decrease linearly with the logarithm of time. Mechanisms are suggested for the observed effects.

scholarly journals Preparation and studying Structural and Electrical properties of nano Co3O4

2019 ◽  
Vol 24 (6) ◽  
pp. 126
Author(s):  
Nawar Thamer Mohammed ◽  
Wasfi Mohammed Kadem
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Sol Gel ◽  
Frequency Range ◽  
Nano Powder ◽  
Structural And Electrical Properties ◽  
Electrical And Dielectric Properties ◽  
Lcr Meter

In this study (Cobalt oxide) nano powder prepared using sol-gel method with a crystallite size 22 nm By testing XRD  and by matching with card (JCPDS) files No.( 00-042-1467). Electrical and dielectric properties like (Dielectric constant, resistivity, electrical conductivity) are studied by LCR meter with frequency range from (50 Hz) to (5 MHz ). It was noted that the resistivity and dielectric constant was decreasing while electrical conductivity increased with increased  frequency    http://dx.doi.org/10.25130/tjps.24.2019.118  

scholarly journals Effect of Doping on the Electrical Characteristics of ZnSe

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 551
Author(s):  
Narsingh Bahadur Singh ◽  
Ching-Hua Su ◽  
Fow-Sen Choa ◽  
Bradley Arnold ◽  
Puneet Gill ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Resistivity ◽  
Electrical Characteristics ◽  
Frequency Range ◽  
Chromium Doping ◽  
Lower Dielectric Constant ◽  
Lcr Meter ◽  
Measured Resistivity ◽  
Transport Method ◽  
Very High

The effect of sulfur, iron, and chromium doping on the electrical characteristics of ZnSe single crystals was studied. The crystals, grown by the physical vapor transport method (PVT) at NASA Marshall Space Flight Center, were characterized by measuring electrical resistivity, capacitance, and dielectric constant using LCR meter. The morphology was studied by scanning electron microscopy to determine the crystallinity and micro defects. The measured resistivity and dielectric constant showed tunability as the function of frequency in the range of 100 Hz to 100,000 Hz, indicating the suitability of doped material for tuning devices. Besides, for the range from 50 mV to 1000mV, there was no difference in values for the studied frequency range, indicating no degradation or breakdown in the material. All doped ZnSe crystals with sulfur, iron, and chromium showed a similar trend as the function of frequency. Cr-ZnSe showed very high resistivity and lower dielectric constant compared to S-ZnSe and Fe-ZnSe crystals.

Mechanism of irregular crack-propagation in thermal controlled fracture of ceramics induced by microwave

2020 ◽  
Vol 21 (6) ◽  
pp. 610
Author(s):  
Xiaoliang Cheng ◽  
Chunyang Zhao ◽  
Hailong Wang ◽  
Yang Wang ◽  
Zhenlong Wang
Keyword(s):  
Crack Propagation ◽  
Industrial Application ◽  
Ceramic Materials ◽  
Advanced Technology ◽  
Analytical Models ◽  
Propagation Mechanism ◽  
Unstable Crack ◽  
Fracture Simulation ◽  
Initial Stage ◽  
Controlled Fracture

Microwave cutting glass and ceramics based on thermal controlled fracture method has gained much attention recently for its advantages in lower energy-consumption and higher efficiency than conventional processing method. However, the irregular crack-propagation is problematic in this procedure, which hinders the industrial application of this advanced technology. In this study, the irregular crack-propagation is summarized as the unstable propagation in the initial stage, the deviated propagation in the middle stage, and the non-penetrating propagation in the end segment based on experimental work. Method for predicting the unstable propagation in the initial stage has been developed by combining analytical models with thermal-fracture simulation. Experimental results show good agreement with the prediction results, and the relative deviation between them can be <5% in cutting of some ceramics. The mechanism of deviated propagation and the non-penetrating propagation have been revealed by simulation and theoretical analysis. Since this study provides effective methods to predict unstable crack-propagation in the initial stage and understand the irregular propagation mechanism in the whole crack-propagation stage in microwave cutting ceramics, it is of great significance to the industrial application of thermal controlled fracture method for cutting ceramic materials using microwave.

Plasticizer effect on dielectric properties of poly(methyl methacrylate)/titanium dioxide composites

2021 ◽  
pp. 096739112110147
Author(s):  
Ufuk Abaci ◽  
H Yuksel Guney ◽  
Mesut Yilmazoglu
Keyword(s):  
Dielectric Constant ◽  
Titanium Dioxide ◽  
Dielectric Properties ◽  
Methyl Methacrylate ◽  
Pure Pmma ◽  
Segmental Mobility ◽  
Scanning Calorimetry ◽  
Poly Methyl Methacrylate ◽  
Casting Technique ◽  
Lcr Meter

The effect of plasticizer on dielectric properties of poly(methyl methacrylate) (PMMA)/titanium dioxide (TiO2) composites was investigated. Propylene carbonate (PC) was used as plasticizer in the samples which were prepared with the conventional solvent casting technique. Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM-EDX) and Differential scanning calorimetry (DSC) analyses and LCR Meter measurements (performed between 300 K and 400 K), were conducted to examine the properties of the composites. With the addition of plasticizer, the thermal properties have changed and the dielectric constant of the composite has increased significantly. The glass transition temperature of pure PMMA measured 121.7°C and this value did not change significantly with the addition of TiO2, however, 112°C was measured in the sample with the addition 4 ml of PC. While the dielectric constant of pure PMMA was 3.64, the ε′ value increased to 5.66 with the addition of TiO2 and reached 12.6 with the addition of 4 ml PC. These changes have been attributed to increase in amorphous ratio that facilitates polymer dipolar and segmental mobility.

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