scholarly journals Temperature Influence on PI/Si3N4 Nanocomposite Dielectric Properties: A Multiscale Approach

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1936
Author(s):  
Mohammed Houssat ◽  
Christina Villeneuve-Faure ◽  
Nadine Lahoud Lahoud Dignat ◽  
Marie-Laure Locatelli ◽  
Jean-Pascal Cambronne
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Strong Correlation ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Multiscale Approach ◽  
Macro Scale ◽  
The Matrix ◽  
Underlying Mechanisms ◽  
Nanocomposite Dielectric

The interphase area appears to have a great impact on nanocomposite (NC) dielectric properties. However, the underlying mechanisms are still poorly understood, mainly because the interphase properties remain unknown. This is even more true if the temperature increases. In this study, a multiscale characterization of polyimide/silicon nitride (PI/Si3N4) NC dielectric properties is performed at various temperatures. Using a nanomechanical characterization approach, the interphase width was estimated to be 30 ± 2 nm and 42 ± 3 nm for untreated and silane-treated nanoparticles, respectively. At room temperature, the interphase dielectric permittivity is lower than that of the matrix. It increases with the temperature, and at 150 °C, the interphase and matrix permittivities reach the same value. At the macroscale, an improvement of the dielectric breakdown is observed at high temperature (by a factor of 2 at 300 °C) for NC compared to neat PI. The comparison between nano- and macro-scale measurements leads to the understanding of a strong correlation between interphase properties and NC ones. Indeed, the NC macroscopic dielectric permittivity is well reproduced from nanoscale permittivity results using mixing laws. Finally, a strong correlation between the interphase dielectric permittivity and NC breakdown strength is observed.

Influence of Chromium Ions on the Dielectric Properties of the PbO-Ga2O3-P2O5 Glass System

2007 ◽  
Vol 62 (5-6) ◽  
pp. 315-323 ◽  
Author(s):  
Gnanaprakasm Little Flower ◽  
Maddireddy Srinivasa Reddy ◽  
Musugu Venkata Ramana Reddy ◽  
Nalluri Veeraiah
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Dielectric Properties ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Oxidation States ◽  
Optical Absorption Spectra ◽  
Dielectric Breakdown Strength ◽  
Chromium Ions ◽  
Wide Range

PbO-Ga2O3-P2O5 glasses containing different amounts of Cr2O3, ranging from 0 to 1.0 mol%, were prepared. The dielectric properties (viz., constant ε’, loss tanδ , ac conductivity σac over a wide range of frequencies and temperatures, dielectric breakdown strength) have been studied as a function of the concentration of chromium ions. An anomaly has been observed in the dielectric properties of these glasses, when the concentration of Cr2O3 is about 0.4 mol%. This anomaly has been explained in the light of different oxidation states of chromium ions with the aid of data of differential thermal analysis and optical absorption spectra of these glasses.

scholarly journals Effects of Ambient Conditions on the Dielectric Properties of Thermally Sprayed Ceramic Coating

2018 ◽  
Author(s):  
M Niittymäki ◽  
B. Rotthier ◽  
K. Lahti ◽  
T. Suhonen ◽  
J Metsäjoki
Keyword(s):  
Dielectric Properties ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Alumina Coating ◽  
Ambient Conditions ◽  
Coating Materials ◽  
Sprayed Coating ◽  
Thermally Sprayed

<p>Thermal spraying techniques are used to manufacture insulating coatings especially for demanding applications like fuel cells where normal insulating materials cannot be used. In electrical insulation applications, the mostly used coating materials are aluminum oxide (Al2O3), magnesium oxide (MgO) and magnesium aluminate (MgAl2O4). Dielectric properties of thermally sprayed ceramic coatings are strongly affected by ambient conditions, and in addition to this they are not well documented in the literature. In this paper the effects of environmental conditions on certain dielectric properties of a thermally sprayed coating are studied. DC resistivity as well as permittivity and losses at different frequencies at relative humidities of 20 % and 45 % at temperature of 20 °C, 40 °C and 60 °C will be reported in the paper for Al2O3 samples sprayed using HVOF (High Velocity Oxygen Fuel) technique. DC dielectric breakdown strength is also studied for the HVOF alumina coating at temperature of 20 °C and relative humidity of 20 %. Effects of ambient conditions and coating material composition are also analyzed.</p>

Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on dipolar copolymers

Polymer ◽  
2014 ◽  
Vol 55 (24) ◽  
pp. 6212-6219 ◽  
Author(s):  
Frederikke Bahrt Madsen ◽  
Liyun Yu ◽  
Anders Egede Daugaard ◽  
Søren Hvilsted ◽  
Anne Ladegaard Skov
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Silicone Elastomers ◽  
Dielectric Breakdown Strength ◽  
High Dielectric Permittivity ◽  
Strength Based ◽  
High Dielectric

scholarly journals Effect of alumina shapes on dielectric properties of UV-cured epoxy acrylic composite with alumina

2019 ◽  
Vol 6 (1) ◽  
pp. 181509 ◽  
Author(s):  
Jiepeng Bian ◽  
Qiuli Zhao ◽  
Zhenzhong Hou ◽  
Jie Dong ◽  
Qinghao Yang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Breakdown Strength ◽  
Low Dielectric ◽  
The Matrix ◽  
High Dielectric ◽  
Processing Properties ◽  
Spherical Alumina ◽  
Properties Of Composites

Polymer-based composites with the advantages of ceramics and polymers exhibit high dielectric constant, good processing properties and low dielectric loss. The composites with a varied content of irregular alumina ( i -Al 2 O 3 ) filler were prepared by UV-cured epoxy acrylic (EA). Spherical alumina ( s -Al 2 O 3 ) was used as a filler to further investigate the effect of alumina (Al 2 O 3 ) shapes on dielectric properties of composites in the frequency range of 50 Hz–1 MHz. Fourier transform infrared spectroscopy proved that the UV-cured epoxy acrylic/alumina (Al 2 O 3 /EA) composites were successfully fabricated. Scanning electron microscopy demonstrated that i -Al 2 O 3 particles have superior homodispersion in the matrix. Through testing, for all samples, with the addition of Al 2 O 3 , the relative permittivity of composites increased as expected, and the dielectric loss decreased accordingly. These data show that the incorporation of i -Al 2 O 3 particles presents better properties when compared with s -Al 2 O 3 /EA, which indicates that i -Al 2 O 3 particles have more influence on the dielectric properties of the composites than those of s -Al 2 O 3 particles. According to Weibull distribution, the characteristic breakdown strength of the Al 2 O 3 /EA composites was obtained and the results suggested that the composites of i -Al 2 O 3 /EA exhibited better breakdown performance.

scholarly journals Improved Dielectric Properties of Thermoplastic Polyurethane Elastomer Filled with Core–Shell Structured PDA@TiC Particles

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3341
Author(s):  
Xinfu He ◽  
Jun Zhou ◽  
Liuyan Jin ◽  
Xueying Long ◽  
Hongju Wu ◽  
...  
Keyword(s):  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Thermoplastic Polyurethane ◽  
Low Loss ◽  
Elongation At Break ◽  
The Matrix ◽  
Potential Applications ◽  
Low Levels ◽  
Surface Modified ◽  
Dielectric And Mechanical Properties

Insulating interlayer between nanoparticles and polymer matrix is crucial for suppressing the dielectric loss of polymer composites. In this study, titanium carbide (TiC) particles were surface modified by polydopamine (PDA), and the obtained PDA@TiC powders were used to reinforce thermoplastic polyurethane (TPU). The results indicate that the PDA@TiC were homogenously dispersed in the matrix compared with the pristine TiC, and that the PDA@TiC/TPU composites show improved dielectric and mechanical properties, i.e., much lower dissipation factors and obviously enhanced dielectric breakdown strength, as well as higher tensile strength and elongation at break as compared to the raw TiC/TPU. The nanoscale PDA interlayer contributes to the dielectric and mechanical enhancements because it not only serves as an insulating shell that prevents TiC particles from direct contacting and suppresses the loss and leakage current to very low levels, but also enhances the interfacial interactions thereby leading to improved mechanical strength and toughness. The prepared flexible PDA@TiC/TPU with high permittivity but low loss will find potential applications in electronic and electrical applications.

Effect of the Difference in Dielectric Constant of the Phases on Dielectric Property of the Composites

2015 ◽  
Vol 814 ◽  
pp. 137-143
Author(s):  
Hao Zhou ◽  
Qing Meng Zhang ◽  
Qun Tang ◽  
Hang Cui ◽  
Yao Hua Xu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
High Dielectric Constant ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Ferroelectric Properties ◽  
Relative Dielectric Constant ◽  
Practical Application ◽  
The Difference ◽  
High Dielectric

The composites have a great use in practical application. In common, the phases in composite have different relative dielectric constant and in order to reveal how the phases with different permittivity affect the composite’s dielectric properties, the experiments were carried out using inorganic and organic composite with different dielectric constant phases to make that clear. The barium niobate-based SiO2system glass–ceramic and fillers-epoxy resin composites were chosen, and the dielectric properties were tested to compare the difference of those composites. The results show that the existence of high dielectric constant phases in composites can improve the permittivity of composites and make the composites present ferroelectric properties, while the dielectric loss can also increased, and the difference in dielectric constant of the phases can decrease the dielectric breakdown strength.

Dielectric Properties of BST/(Y2O3)x(ZrO2)1-x/BST Trilayer Films

2011 ◽  
Vol 1292 ◽  
Author(s):  
Santosh K. Sahoo ◽  
D. Misra
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Sol Gel ◽  
Middle Layer ◽  
Slight Variation ◽  
High Dielectric

ABSTRACTThin films of Ba1-xSrxTiO3 (BST) are being actively investigated for applications in dynamic random access memories (DRAM) because of their properties such as high dielectric constant, low leakage current, and high dielectric breakdown strength. Various approaches have been used to improve the dielectric properties of BST thin films such as doping, graded compositions, and multilayer structures. We have found that inserting a ZrO2 layer in between two BST layers results in a significant reduction in dielectric constant as well as dielectric loss. In this work the effect of Y2O3 doped ZrO2 on the dielectric properties of BST/ZrO2/BST trilayer structure is studied. The structure Ba0.8Sr0.2TiO3/(Y2O3)x(ZrO2)1-x/Ba0.8Sr0.2TiO3 is deposited by a sol-gel process on platinized Si substrate. The composition (x) of the middle layer is varied while keeping the total thickness of the trilayer film constant. The dielectric constant of the multilayer film decreases with the increase of Y2O3 amount in the film whereas there is a slight variation in dielectric loss. In Y2O3 doped multilayer thin films, the dielectric loss is lower in comparison to other films and also there is good frequency stability in the loss in the measured frequency range and hence very suitable for microwave device applications.

Mechanical and dielectric properties of epoxy composites filled with hybrid aluminum particles with binary size distribution

2017 ◽  
Vol 31 (1) ◽  
pp. 124-134 ◽  
Author(s):  
Ying Gong ◽  
Wenying Zhou ◽  
Xuezhen Sui ◽  
Yujia Kou ◽  
Li Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dielectric Properties ◽  
Size Distribution ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Relative Weight ◽  
Volume Resistivity ◽  
Epoxy Composites ◽  
Hybrid Particles ◽  
Hybrid Filler

Epoxy composites incorporated with three kinds of hybrid aluminum (Al) particles with binary size distribution, that is, [1 μm/45 μm], [1 μm/18 μm], and [18 μm/45 μm], respectively, were prepared, and the mechanical and dielectric properties of the hybrid Al/epoxy composites were investigated as a function of relative weight fraction of smaller-size Al ( Ws) of hybrid Al particles at a total filler content of 50 wt%. The mechanical and electrical properties of the hybrid Al/epoxy composites are found to mainly depend on the type of hybrid filler and the Ws and can be tuned by changing the Ws. The maximum tensile strength and elongation at break of the composites appear at an optimal Ws. Furthermore, the dielectric permittivity, dielectric breakdown strength, and volume resistivity of the hybrid Al/epoxy composites also exhibit the similar variations as the mechanical properties with the Ws. The obvious enhancements in the physical properties can be ascribed to the synergistic effect of hybrid particles in the matrix at the optimal Ws, which endows the composites with better mechanical and dielectric properties. So, the results give a facile strategy to enhance the dielectric and mechanical properties of the composites by choosing a proper Ws at a fixed total filler loading.

Dielectric Breakdown Strength and Microwave Dielectric Properties of Alumina Ceramics with CaO-SiO2- MgO, Yb2O3 and ZrO2 Additives

2018 ◽  
Vol 281 ◽  
pp. 640-645
Author(s):  
Gui Fen Fan ◽  
Hao Yuan Deng ◽  
Meng Meng Hao ◽  
Kai Wang ◽  
Yu Sheng Shi ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Alumina Ceramics ◽  
Conventional Solid State Reaction ◽  
Dielectric Breakdown Strength ◽  
Microwave Dielectric ◽  
Maximum Value

Al2O3 ceramics with CaO-SiO2-MgO (CMS), Yb2O3 and ZrO2 additives were fabricated by a conventional solid-state reaction method. The effects of ZrO2 dopant on phase compositions, microwave dielectric properties and dielectric breakdown strength of Al2O3 ceramics were studied. XRD demonstrated that CaAl2Si2O8 and Zr &Y compound phases co-existed with alumina. SEM exhibited that ZrO2 dopant could refine the grain of alumina ceramics and improve its relative density. With ZrO2 content increasing from 1wt% to 5wt% εr increased from 9.8 to 10.25, but Q×f decreased from 52823GHz to 35922GHz. The breakdown strength increased initially and reached the maximum value at ZrO2=3wt%. When ZrO2 content is 3wt%, the comprehensive performances were the best: Eb= 37.37kV/mm for 1mm samples and 17.26kV/mm for 3mm samples, Q×f = 37044 GHz, εr = 10.01, and τf = -52 ppm/°C.

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