scholarly journals Broadband dielectric response of AlN ceramic composites

2014 ◽  
Vol 8 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Iryna Brodnikovska ◽  
Andriy Deriy ◽  
Vitaly Petrovsky
Keyword(s):  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Dielectric Response ◽  
Sintering Temperature ◽  
Dielectric Permeability ◽  
Ceramic Composites ◽  
Substrate Material ◽  
Nondestructive Method ◽  
Broadband Dielectric Spectroscopy

Aluminium nitride (AlN) is considered as a substrate material for microelectronic applications. AlN ceramic composites with different amount of TiO2 (up to 4 vol.%) were obtained using hot pressing at different sintering temperature from 1700 to 1900 ?C. It was shown that milling of the raw AlN powder has strongly influence on sintering and improves densification. Broadband dielectric spectroscopy was used as a nondestructive method for monitoring of the ceramic microstructures. TiO2 additive affects the key properties of AlN ceramics. Thus, porosity of 0.1%, dielectric permeability of ? = 9.7 and dielectric loss tangent of tan? = 1.3?10-3 can be achieved if up to 2 vol.% TiO2 is added.

Spark Plasma Sintered AlN-BN Composites and its Dielectric Properties

2008 ◽  
Vol 368-372 ◽  
pp. 940-942
Author(s):  
Hai Yang Zhao ◽  
Wei Min Wang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Sintering Temperature ◽  
Hexagonal Boron Nitride ◽  
Relative Dielectric Constant ◽  
Ceramic Composites ◽  
Spark Plasma

A series of samples of hexagonal boron nitride-aluminum nitride (10-90, 15-85, 20-80, 25-75, 30-70wt.%) ceramic composites were prepared by spark plasma sintering in a nitrogen atmosphere at 1650 °C-1800 °C for 5min. Different amounts of CaF2 were added as sintering aids. The effects of CaF2 and sintering temperature on densification and dielectric properties were discussed. The addition of CaF2 enhances relative dielectric constant and loss tangent of the samples. The increase in sintering temperature promotes the densification and decreases the dielectric loss tangent. When being sintered at 1700 °C, the relative density, dielectric constant and dielectric loss tangent of the sample with 15wt.%BN are 98.04%, 7.15 and 6.31×10-4 respectively.

REVISIT TO DIELECTRIC PROPERTIES OF FERRITE CERAMICS

2012 ◽  
Vol 02 (03) ◽  
pp. 1230010 ◽  
Author(s):  
L. B. KONG ◽  
L. LIU ◽  
J. W. ZHAI ◽  
Z. W. LI ◽  
Z. H. YANG
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Sintering Temperature ◽  
Short Review ◽  
Sintering Aids ◽  
Time Duration ◽  
Sintering Aid ◽  
Low Dielectric

Dielectric properties of ferrite ceramics have been less reported than their magnetic properties. Our recent study indicated that ferrite ceramics with very low dielectric loss tangent can be developed by using appropriate sintering aids, together with the optimization of other sintering parameters such as sintering temperature and time duration. Among various candidates of sintering aids, Bi 2 O 3 is the most promising one. It is important to find that the optimized concentration of sintering aid for full densification is not sufficient to achieve lowest dielectric loss tangent. This short review was aimed to summarize the understanding in microstructural evolution, grain growth, densification and dielectric properties of ferrite ceramics as a function of sintering aid concentration and sintering parameters, which could be used as a guidance to develop ferrite ceramics with low dielectric loss tangents for various applications.

Electrophysical properties of mixtures of mineral oil and synthetic ester dielectric liquid

2021 ◽  
Vol 14 (2) ◽  
pp. 132-141
Author(s):  
M. N. Lyutikova ◽  
S. M. Korobeynikov ◽  
A. A. Konovalov
Keyword(s):  
Dielectric Loss ◽  
Breakdown Voltage ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Kinematic Viscosity ◽  
Mineral Oil ◽  
Flash Point ◽  
Power Transformers ◽  
Synthetic Ester ◽  
Insulating Properties

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.

Method of calculating the dielectric loss tangent of binary systems

1987 ◽  
Vol 52 (3) ◽  
pp. 310-312
Author(s):  
G. N. Dul'nev ◽  
D. P. Volkov ◽  
M. V. Dobrochasov
Keyword(s):  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Binary Systems

scholarly journals Dielectric and electrical properties of Cr substituted Mg ferrites

2015 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
AKM Zakaria ◽  
Faizun Nesa ◽  
MA Saeed Khan ◽  
SM Yunus ◽  
NI Khan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Lattice Parameter ◽  
Activation Energies ◽  
X Ray Diffraction ◽  
Constant E ◽  
Cr Concentration ◽  
Academy Of Sciences

The spinel ferrites MgCrxFe2-xO4 (0.0 ? × ?1.0) were prepared through the solid state reaction using conventional ceramic method at 1300°C in air. The homogeneous phase of the ferrite samples was observed from the X-ray diffraction study. Lattice parameter of the samples was found to decrease with increasing Cr concentration in the system obeying Vegard’s law. The ac electrical resistivity, measured as a function of temperature, decreases with the increase of temperature indicating the semiconducting nature of all the samples. The activation energies were calculated and found to decrease with increasing Cr content. The lower activation energies are associated with higher electrical conductivity. With the increase of temperature, dielectric constant (e`) and dielectric loss tangent are observed to be increased; while with the increase of frequency, dielectric constant (e`) and dielectric loss tangent decrease for all the samples.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 1-12, 2015

Multipurpose Nonwoven Viscose/Polypropylene Fabrics: Effect of Fabric Characteristics and Humidity Conditions on the Volume Electrical Resistivity and Dielectric Loss Tangent

2020 ◽  
Vol 21 (10) ◽  
pp. 2407-2416
Author(s):  
Koviljka A. Asanovic ◽  
Dragana D. Cerovic ◽  
Mirjana M. Kostic ◽  
Tatjana V. Mihailovic ◽  
Aleksandra M. Ivanovska
Keyword(s):  
Electrical Resistivity ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent

scholarly journals In-situ measurement of electric current and dielectric loss tangent during vulcanisation of nitrile rubber.

1998 ◽  
Vol 71 (5) ◽  
pp. 281-285 ◽  
Author(s):  
Toyohiko GONDOH ◽  
Yukiko MATSUOKA ◽  
Michiharu TOH ◽  
Daisaburo OKAI ◽  
Tetsuo MORI
Keyword(s):  
Dielectric Loss ◽  
Electric Current ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Nitrile Rubber ◽  
In Situ Measurement

Dielectric loss tangent of sapphire single crystal produced by edge-defined film-fed growth method

2002 ◽  
Vol 377 (3) ◽  
pp. 313-318 ◽  
Author(s):  
M. Kusunoki ◽  
M. Inadomaru ◽  
S. Ohshima ◽  
K. Aizawa ◽  
M. Mukaida ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Single Crystal ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Growth Method ◽  
Sapphire Single Crystal

Role of Donor and Acceptor Ions in the Dielectric Loss Tangent of (Zr0.8Sn0.2)TiO4 Dielectric Resonator Material

1995 ◽  
Vol 78 (3) ◽  
pp. 793-796 ◽  
Author(s):  
Nobuhiko Michiura ◽  
Tsutomu Tatekawa ◽  
Yukio Higuchi ◽  
Hiroshi Tamura
Keyword(s):  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Dielectric Resonator ◽  
Donor And Acceptor
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