scholarly journals Ferroelectric, Piezoelectric and Dielectric Properties of Novel Polymer Nanocomposites

2021 ◽  
Author(s):  
Maheswar Panda
Keyword(s):  
Dielectric Properties ◽  
Interfacial Polarization ◽  
Electrical Energy ◽  
Dielectric Behavior ◽  
Effective Dielectric Constant ◽  
The Novel ◽  
Cold Pressing ◽  
Polymer Metal ◽  
Tan Δ ◽  
Ceramic Fillers

In this chapter, the Ferroelectric, Piezoelectric and Dielectric behavior of novel polymer/ceramic nano-composite (PCC) based on ferroelectric polymer [polyvinyledene fluoride (PVDF)] & nano Barium Titanate (n-BaTiO3) with different volume fractions of n-BaTiO3 (fBaTiO3), prepared through the novel cold pressing method has been discussed. The ferroelectric parameters of PCC are attributed to spherulites of PVDF, the increase of n-BaTiO3 and the ordered homogenous structure due to the novel cold pressing. The clustering of ceramic fillers is responsible for randomization of the structures of these composite ferroelectrics for some samples, leading to decrease of electrical polarisations. The piezoelectricity and piezoelectric coefficients of these composites ferroelectrics, increases with increase of ceramic filer content and remains constant beyond a certain ratio. However, the dielectric properties increase linearly as a function of ceramic content due to increase of interfaces/interfacial polarisations. The enhancement of effective dielectric constant (ɛeff) is attributed to the large interfacial polarization arising due to the charge storage at the spherulites of PVDF and at the polymer/filler interfaces of PCC and have been explained on the basis of sum effect with the help of the standard models. The achieved lower loss tangent (Tan δ) for the PCC as compared to the polymer/metal composites (PMC) is attributed to the highly insulating nature of PVDF & semiconducting n-BaTiO3. The thermal stability of the composites is also maintained due to the higher melting temperature (170°C) of PVDF. The cold pressed PCC based on PVDF are going to act as better polymer ferroelectric/dielectrics for memory and electrical energy storage applications.

Percolation behavior of polymer/metal composites on modification of filler

2014 ◽  
Vol 28 (07) ◽  
pp. 1450055 ◽  
Author(s):  
M. Panda ◽  
V. Srinivas ◽  
A. K. Thakur
Keyword(s):  
Critical Exponents ◽  
Effective Dielectric Constant ◽  
Core Shell ◽  
Metal Composites ◽  
Percolation Behavior ◽  
Swiss Cheese Model ◽  
Polymer Metal ◽  
The Difference ◽  
Tan Δ ◽  
Cheese Model

Polymer–metal composites with different fillers, such as nanocrystalline nickel (n- Ni ), core shell n- Ni and nickel oxide ( NiO )[n- Ni@NiO ] were prepared under the same processing conditions with polyvinyledene fluoride matrix. The larger value of critical exponents (s and s') and percolation threshold (fc ~ 0.30) for n- Ni@NiO composites as compared to n- Ni composites (fc ~ 0.07) and a comparable effective dielectric constant (ε eff ~ 300) with low loss tangent ( t an δ ~ 0.1) at 100 Hz in case of percolative n- Ni@NiO composite was observed. The core shell structure [n- Ni@NiO ] also shows a very high value of ε eff ~ 6000 with tan δ ~ 8 at 40 Hz. The results have been explained by using boundary layer capacitor effect and the percolation theory. The difference in fc and critical exponents is attributed to NiO insulating layer that gives rise to different extent of continuumness at fc and have been explained with the help of Swiss cheese model.

Dielectric Properties of W-Type BaCa2Fe16O27 Hexaferrite Prepared Using a Stearic Acid Gel Route

2013 ◽  
Vol 665 ◽  
pp. 210-213 ◽  
Author(s):  
Chetna C. Chauhan ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Stearic Acid ◽  
Room Temperature ◽  
Conduction Mechanism ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Tan Δ ◽  
Acid Gel ◽  
Hopping Model

W-type hexagonal ferrite with composition BaCa2Fe16O27 was prepared using a stearic acid gel method. The precipitate of barium calcium hexaferrite was calcinated at 650°C, 750°C, 850°C and 950°C in a furnace for 4 hours and then slowly cooled to room temperature. The dielectric constants (real Є and imaginary Є), conductivity (σ) and dielectric loss (tan δ) have been measured at room temperature as a function of frequency (102-106 Hz). The dielectric behavior of prepared hexaferrite samples can be explained by the mechanism of polarization and the electrical conduction mechanism is explained by using the electronic hopping model of Heike Johnson.

EFFECT OF SINTERING TEMPERATURE ON THE STRUCTURAL AND DIELECTRIC PROPERTIES OF ZINC CADMIUM FERRITES PREPARED BY EGG-WHITE TECHNIQUE

2010 ◽  
Vol 24 (17) ◽  
pp. 1907-1914 ◽  
Author(s):  
M. ABDULLAH DAR ◽  
W. A. SIDDIQUI ◽  
M. ALAM
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Interfacial Polarization ◽  
Phenomenological Theory ◽  
Egg White ◽  
Frequency Range ◽  
Wagner Model ◽  
Maximum Value ◽  
Zinc Cadmium ◽  
Tan Δ

The effect of cadmium substitution and sintering temperature on the microstructure and dielectric properties of nano ZnCd x Fe 2-x O 4 ferrites (x=0.0, 0.05, 0.1, 0.2, 0.3 and 0.5) has been investigated and prepared by egg-white technique. Electrical conductivity and dielectric measurements have been analysed in the frequency range from 100 Hz to 10 MHz. The variation of the real (ε′) and imaginary (ε″) part of dielectric constant, AC conductivity (σ AC ) and loss tangent ( tan δ) with frequency has been studied. It follows the Maxwell–Wagner model based on the interfacial polarization in consonance with the Koop's phenomenological theory. It is found that the permittivity of ZnCd x Fe 2-x O 4 ferrites improved and shows a maximum value (~9 × 103) at 100 Hz for the x=0.1 sample.

Influence of Ca-Doping on Structural, Magnetic and Dielectric Properties of Ba3Co2-xCaxFe24O41 Hexaferrite Powders

2015 ◽  
Vol 241 ◽  
pp. 226-236 ◽  
Author(s):  
Neha Solanki ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Calcium Content ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Ca Doping ◽  
Auto Combustion ◽  
Magnetic And Dielectric Properties

Influence of Ca substitution on structural, magnetic and dielectric properties of Ba3Co2-xCaxFe24O41(where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), prepared by Sol-Gel auto-combustion method, has been investigated in present studies. The obtained powder was sintered at 950 oC for 4 hrs. in the static air atmosphere. Structural analysis of Ca-doped Ba3Co2-xCaxFe24O41powders revealed pure Z-type hexaferrite phase at low temperature. The frequency dependent dielectric constant (Єʹ) and magnetic properties such as remanent magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were studied. It is observed that coercivity increased gradually with increase in calcium content. The real dielectric constant (Єʹ) and dielectric loss tangent (tan δ) were studied in the frequency range of 20Hz to 2MHz. The dielectric parameters for all samples show normal dielectric behavior as observed in hexaferrites. Contents of Paper

Enhanced dielectric properties of PVDF-HFP/BaTiO3-nanowire composites induced by interfacial polarization and wire-shape

2015 ◽  
Vol 3 (6) ◽  
pp. 1250-1260 ◽  
Author(s):  
Y. Feng ◽  
W. L. Li ◽  
Y. F. Hou ◽  
Y. Yu ◽  
W. P. Cao ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Interfacial Polarization ◽  
Inorganic Content

A high-ε polymer based composite with lower inorganic content (≤10 vol%) has been fabricated using BaTiO3 nanowires as fillers.

Crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 tungsten–bronze glass–ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 2057-2063 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Hsin-Wei Peng
Keyword(s):  
Heat Treatment ◽  
Dielectric Properties ◽  
Tungsten Bronze ◽  
Glass Ceramics ◽  
Dielectric Behavior ◽  
Dendritic Morphology ◽  
Dielectric Constants ◽  
Two Stage ◽  
Tetragonal Tungsten Bronze ◽  
Stage Heat Treatment

The crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 glass–ceramics were investigated. One- and two-stage heat-treatment methods were used to convert the parent glass to glass–ceramics. Strontium barium niobate (SBN) with a tetragonal tungsten-bronze structure formed as the major crystalline phase. When the crystallizing temperature/time was increased, the secondary crystalline BaGe2O5 phase coexisted with SBN. BaGe2O5 formed as a surface layer grown from the surface into the interior of the sample. The dendritic morphology of SBN crystals was examined. The glass–ceramics crystallized by two-stage heat treatment have higher dielectric constants than those crystallized by one-stage heat treatment. The highest dielectric constant that was obtained in the present glass–ceramics was 320. The glass–ceramics showed relaxor-type dielectric behavior.

scholarly journals Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1812
Author(s):  
Qin Gang ◽  
Rong-Tsu Wang ◽  
Jung-Chang Wang
Keyword(s):  
Thermal Conductivity ◽  
Power Density ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Steel Tube ◽  
Storage Device ◽  
Stainless Steel Tube ◽  
The Novel ◽  
Empirical Formulas ◽  
Dissipative Heat

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.

ON THE DIELECTRIC BEHAVIOR OF LiCo3/5Fe2/5VO4 CERAMICS

2010 ◽  
Vol 24 (07) ◽  
pp. 665-670
Author(s):  
MOTI RAM
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Frequency Dependence ◽  
Chemical Method ◽  
Arrhenius Plot ◽  
Dielectric Behavior ◽  
Tangent Loss ◽  
Low Frequencies ◽  
Different Temperatures ◽  
Tan Δ

The LiCo 3/5 Fe 2/5 VO 4 ceramics has been fabricated by solution-based chemical method. Frequency dependence of the dielectric constant (εr) at different temperatures exhibits a dispersive behavior at low frequencies. Temperature dependence of εr at different frequencies indicates the dielectric anomalies in εr at Tc (transition temperature) = 190°C, 223°C, 263°C and 283°C with (εr) max ~ 5370, 1976, 690 and 429 for 1, 10, 50 and 100 kHz, respectively. Frequency dependence of tangent loss ( tan δ) at different temperatures indicates the presence of dielectric relaxation in the material. The value of activation energy estimated from the Arrhenius plot of log (τd) with 103/T is ~(0.396 ± 0.012) eV.

Interfacial polarization effects on dielectric properties in flax reinforced polypropylene/strontium titanate composites

2021 ◽  
pp. 124489
Author(s):  
P.V.S. Hari Prashanth ◽  
Elammaran Jayamani ◽  
Kok Heng Soon ◽  
Yat Choy Wong ◽  
Mohammed Rezaur Rahman ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Strontium Titanate ◽  
Interfacial Polarization ◽  
Polarization Effects

scholarly journals Microwave enhanced roasting for pyrite ore samples with dielectric properties strongly dependent on temperature

2015 ◽  
Vol 20 (1) ◽  
Author(s):  
Manuel Diaz ◽  
Ivan Amaya ◽  
Rodrigo Correa
Keyword(s):  
Experimental Data ◽  
Dielectric Properties ◽  
Processing Time ◽  
Gaussian Model ◽  
Single Mode ◽  
Electrical Energy ◽  
Electrical Energy Consumption ◽  
Pilot Plant Scale ◽  
Heating Behavior ◽  
Better Than

<p>This article shows the main experimental results related to the measurement of dielectric properties of Pyrite ore mineral samples as a function of temperature, and their effect on the heating behavior of the samples. It was found that the sample’s dielectric properties strongly depend on temperature. The best model for  and  that fitted the experimental data, was a Gaussian model. Besides, and under certain conditions, it was possible to roast the mineral even better than with an electric furnace, while requiring less processing time and with lower electrical energy consumption. Additional exploratory tests revealed that microwaves can be used to smelt a roasted mineral ore with time reductions of about 90%, while keeping recovery margins above 95%. Thus, we conclude that, as a next stage, the process should be directed to using a single mode applicator, for processing higher volumes of mineral at pilot plant scale.</p>

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