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.

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>

scholarly journals Volume and Surface Resistivity Measurement of Insulating Materials Using Guard-Ring Terminal Electrodes

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2811
Author(s):  
Heon-Gyeong Lee ◽  
Jin-Gyu Kim
Keyword(s):  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Resistivity Measurement ◽  
Volume Resistivity ◽  
Surface Resistivity ◽  
International Standards ◽  
Guard Ring ◽  
International Electrotechnical Commission ◽  
Renewable Energy Resources ◽  
Insulating Materials

Recently, eco-friendly energy conversion policies have been being promoted through de-nuclearization and de-coal. For this purpose, a super grid should be built to optimize sustainable renewable energy resources such as solar and wind power. Accordingly, considering the various problems such as technology and cost, a system for efficient energy transmission is required. Hence, research is being actively conducted to apply it, owing to the development of the high voltage direct current (HVDC) system. Among HVDC systems, the cable system is extremely important, in addition to the measurement of the dielectric breakdown strength, space charge, and volume resistivity of insulating materials. The existing resistivity measurement method measures both the volume and surface resistivity using a three-terminal electrode that is used in the international standards of American Society for Testing and Materials (ASTM) D 257 and International Electrotechnical Commission (IEC) 60093. However, the circuit configuration differs depending on the measurement of the volume and surface resistivity; moreover, when a DC voltage is applied to the insulator, a charging current flows and there are multiple samples to be measured, which takes a considerable amount of time. Therefore, in this study, we proposed a new type of resistivity measurement system that is based on the existing three-terminal electrode system. Furthermore, we produced a system capable of simultaneously measuring the volume and surface resistivity. Finally, using this system, we compared and analyzed the volume and surface resistivity of five insulating materials.

scholarly journals Simultaneously Enhanced Thermal Conductivity and Dielectric Breakdown Strength in Sandwich AlN/Epoxy Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1898
Author(s):  
Zhengdong Wang ◽  
Xiaozhuo Wang ◽  
Silong Wang ◽  
Jieyu He ◽  
Tong Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Layer Thickness ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Electronic Devices ◽  
Epoxy Composites ◽  
Power Equipment ◽  
Power Electronic ◽  
Sandwich Composites ◽  
Dielectric Breakdown Strength

Polymer-based composites with high thermal conductivity and dielectric breakdown strength have gained increasing attention due to their significant application potential in both power electronic devices and power equipment. In this study, we successfully prepared novel sandwich AlN/epoxy composites with various layer thicknesses, showing simultaneously and remarkably enhanced dielectric breakdown strength and thermal conductivity. The most optimized sandwich composite, with an outer layer thickness of 120 μm and an inner layer thickness of 60 μm (abbreviated as 120-60) exhibits a high through-plane thermal conductivity of 0.754 W/(m·K) (4.1 times of epoxy) and has a dielectric breakdown strength of 69.7 kV/mm, 8.1% higher compared to that of epoxy. The sandwich composites also have higher in-plane thermal conductivity (1.88 W/(m·K) for 120-60) based on the novel parallel models. The sandwich composites with desirable thermal and electrical properties are very promising for application in power electronic devices and power equipment.

scholarly journals Experimental Study of Electric and Dielectric Behavior of PVC Composites

2020 ◽  
Vol 10 (1) ◽  
pp. 5233-5236
Author(s):  
L. Madani ◽  
K. S. Belkhir ◽  
S. Belkhiat
Keyword(s):  
Experimental Study ◽  
Titanium Dioxide ◽  
Fourier Transform ◽  
Dielectric Properties ◽  
Breakdown Strength ◽  
Volume Resistivity ◽  
Dielectric Behavior ◽  
Uv Aging ◽  
Impedance Analyzer ◽  
Voltage Breakdown

Polyvinyl chloride (PVC) is usually used as insulation in electrical engineering, mainly as cable insulation sheaths. A method for improving PVC’s dielectric properties, reducing the effects of UV aging, is the use of PVC films doped in alumina and titanium dioxide. This research investigated the influence of alumina and titanium dioxide (Al2O3/TiO2) on the dielectric properties of PVC. Four PVC samples were examined using an RLC impedance analyzer. Fourier Transform Infrared (FTIR) spectroscopy was utilized on the sample’s surfaces, exploring the chemical stability of the tested materials. In addition, the volume resistivity and average breakdown voltage of each sample were examined. Doping Al2O3/TiO2 into PVC improved its dielectric properties and volume resistivity while adding more ceramic decreased volume resistivity. Furthermore, the addition of Al2O3/TiO2 caused a significant enhancement in voltage breakdown strength.

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.

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.

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