scholarly journals Preparation and characterization of isotactic polypropylene/MgO composites as dielectric materials with low dielectric loss

2013 ◽  
Vol 121 (1416) ◽  
pp. 606-610 ◽  
Author(s):  
Susumu TAKAHASHI ◽  
Yusuke IMAI ◽  
Akinori KAN ◽  
Yuji HOTTA ◽  
Hirotaka OGAWA
2009 ◽  
Vol 24 (2) ◽  
pp. 324-332 ◽  
Author(s):  
X.T. Liew ◽  
K.C. Chan ◽  
L.B. Kong

This paper reports on the preparation and characterization of nickel ferrite (NiFe1.98O4) ceramics doped with Bi2O3 as sintering aid. Focus has been on the effects of concentration of Bi2O3 and sintering temperature on the densification, grain growth, dielectric, and magnetic properties of the NiFe1.98O4 ceramics, with an aim at developing magnetodielectric properties, with almost equal real permeability and permittivity, as well as sufficiently low magnetic and dielectric loss tangents, over 3 to 30 MHz (high frequency or HF band). X-ray diffraction results indicated that there is no obvious reaction between NiFe1.98O4 and Bi2O3, at Bi2O3 levels of up to 7 wt% and temperatures up to 1150 °C. The addition of Bi2O3 facilitated a liquid phase sintering mechanism for the densification of NiFe1.98O4 ceramics. The addition of Bi2O3 not only improved the densification but also promoted the grain growth of NiFe1.98O4 ceramics. To achieve sufficiently low dielectric loss tangent, the concentration of Bi2O3 should not be less than 5 wt%. The low dielectric loss tangents of the samples doped with high concentrations of Bi2O3 can be attributed to the full densification of the ceramics. Magnetic properties of the NiFe1.98O4 ceramics, as a function of sintering temperature and Bi2O3 concentration, can be qualitatively explained by the Globus model. Promising magnetodielectric properties have been obtained in the sample doped with 5% Bi2O3 and sintered at 1050 °C for 2 h. The sample has almost equal values of permeability and permittivity of ∼12, together with low dielectric and magnetic loss tangents, over 3 to 30 MHz. This material might be useful for the miniaturization of HF (3 to 30 MHz) antennas.


2013 ◽  
Vol 22 ◽  
pp. 148-152
Author(s):  
DHANESH THOMAS ◽  
M. T. SEBASTIAN

Butyl rubber — Ca 4 La 6( SiO 4)4( PO 4)2 O 2 — composites have been prepared by sigma mixing and hot pressing. The relative permittivity of the composites varies from 3 to 5.3 at 1 MHz. All the composites show low dielectric loss of the order of 10−3 at 1 MHz. The experimentally observed values of relative permittivity are correlated with those calculated using various theoretical models. The composites show good temperature stability of relative permittivity.


1999 ◽  
Vol 565 ◽  
Author(s):  
Chuan Hu ◽  
Michael Morgen ◽  
Paul S. Ho ◽  
Anurag Jain ◽  
William. N. Gill ◽  
...  

AbstractA quantitative characterization of the thermal properties is required to assess the thermal performance of low dielectric constant materials. Recently we have developed a technique based on the 3-omega method for measuring the thermal conductivity of porous dielectric thin films. In this paper we present the results on the measurements of thermal conductivity of thin porous films using this method. A finite element method analysis is used to evaluate the approximations used in the measurement. Two porosity-weighted thermal resistor models are proposed to interpret the results. By studying the dependence of the thermal conductivity on porosity, we are able to discuss the scaling rule of thermal conductivity. Additionally, a steady state layered heater model is used for evaluating the significance of introducing porous ILDs into an interconnect structure.


2021 ◽  
Vol 6 (1) ◽  
pp. 31-35
Author(s):  
Nurul Ainon Bakar ◽  
Muhammad Azwadi Sulaiman ◽  
Julie Juliewatty Mohamed

Nickel oxide (NiO) belongs to the transition metal oxide family, having good dielectric constantwith the range of 103 – 105, but it has high dielectric loss. In this research, the effect of titaniumdioxide (TiO2) addition into NiO was investigated. Generally, TiO2 was used in the application ofelectrical ceramic, catalysts, electric conductors and chemical intermediates. Ni1-xTixO1+x wasprepared via solid-state reaction method with 6 different TiO2 compositions. The preparation startedwith the powder mixing process for 24 hours and followed by calcination process at 950 °C for 4hours. Then, the calcined powders were compacted into 6 mm pellet shape under pressure of 250MPa pressure. Three pellets were made for each TiO2 composition. Those pellets were sintered at1250 °C for 5 hours. XRD results showed that pure NiO at 0.01 and 0.02 mole % of TiO2compositions produced single NiO crystalline phase, while 0.03, 0.05 and 0.10 mol % of TiO2showed the TiO2, instead of NiO phases. SEM analysis showed that increasing TiO2 concentrationmake the grain size increase, with 0.02 mole % of TiO2 gave the largest grain size, shows that 0.02mole % is the optimum TiO2 concentration for grain size enlargement. Furthermore, the bulkdensity of Ni1xTixO1+xpellet was reduces at higher TiO2 concentration. In dielectric test, the additionof 0.03 mole % of TiO2 gave the highest dielectric constant with value of 4.51 x 1014 and 0.05 mole% of TiO2 gives the result of lowest dielectric loss (0.53).


2006 ◽  
Vol 45 ◽  
pp. 2351-2354
Author(s):  
Ji Won Choi ◽  
Chong Yun Kang ◽  
Jin Sang Kim ◽  
Seok Jin Yoon ◽  
Hyun Jai Kim ◽  
...  

The dielectric properties of (Ba,Sr)TiO3 (BSTO) and Zr doped BSTO thin films have been investigated to identify candidate thin film dielectric materials having low dielectric loss without degradation of the tunability by continuous composition spread (CCS) technique using off-axis rf magnetron sputtering. The optimized properties of BSTO thin films deposited on Pt/SiO2/Si substrate by CCS were dielectric loss 0.031, tunability 31.5, respectively. The optimized properties of Zr doped BSTO thin films deposited on Pt/SiO2/Si substrate by CCS were improved by dielectric loss 42%, FOM 68% at the same BSTO composition, respectively. To confirm the dielectric properties and compositions by CCS technique, Zr doped BSTO bulk ceramics were evaluated.


2018 ◽  
Vol 210 ◽  
pp. 301-304 ◽  
Author(s):  
Zhanhui Peng ◽  
Pengfei Liang ◽  
Xing Wang ◽  
Hui Peng ◽  
Xiaofang Chen ◽  
...  

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 83163-83174 ◽  
Author(s):  
Hailin Mo ◽  
Genlin Wang ◽  
Fei Liu ◽  
Pingkai Jiang

Two strategies, including in situ grafting chemicals and polymer coating micas, were used to improve the interface between mica and epoxy matrix. The epoxy composites prepared by strategy I exhibited better overall performance.


2017 ◽  
Vol 1 (4) ◽  
pp. 780-788 ◽  
Author(s):  
Rakesh Manna ◽  
Suneel Kumar Srivastava

XNBR/GNS–HDA nanocomposites exhibited enhanced tensile strength, elongation at break, reduced Young's modulus and high dielectric constants at low dielectric loss.


2021 ◽  
Author(s):  
Salma Aman ◽  
Tahani I. Al-Muhimeed ◽  
Zaki Ismail Zaki ◽  
Zeinhom M. El-Bahy ◽  
Abeer A. AlObaid ◽  
...  

Abstract Spinel ferrites are attractive for high frequency applications due to their larger direct current (dc) resistivity and low dielectric loss. In the present work, Co0.6Zn0.4HoxFe2-xO4 (x = 0.00 and 0.1) spinel ferrites were prepared by sol-gel method. The X-ray diffraction pattern showed that both samples had cubic spinel structure, while in sample (x = 0.1), the secondary phase (HoFeO3) was also observed. The dc resistivity was increased with the addition of holmium ions. As the temperature increased, the dc resistivity was decreased by proving their semiconducting nature. The dielectric properties were also measured as a function of temperature and frequency. The sample which was composed by the substitution of holmium ions contained low value of dielectric loss. The magnetic properties were also experimentally measured by applying the field up to 2000 oersted. The small area covered by hysteresis loop proved that both samples possessed soft nature of magnetic materials.


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