Comparative Study on Electrical and Dielectric Properties of Sintered Nano and Micro Silicon Nitride Ceramics

2016 ◽  
Vol 2 (1) ◽  
pp. 13-18
Author(s):  
Imran Khan ◽  
M S A Khan
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Silicon Nitride ◽  
Dc Conductivity ◽  
Temperature Range ◽  
Nitride Ceramics ◽  
Electrical And Dielectric Properties ◽  
Sintered Silicon

In the present work we have studied the electrical conductivity, dielectric constant and dielectric loss of Sintered Silicon Nitride ceramics. In this study it was found that the grain size has great impact on electrical conductivity and dielectric properties of Sintered Silicon Nitride Ceramics. The result shows more efficiency of electrical and dielectric properties with nano sized grains.  The sintering was performed in a programmable furnace at 950 K. The dc conductivity measured in the temperature range 300 K to 900 K. At higher temperature (T > 800 K), the dc conductivity increases exponentially with temperature for both of the investigated samples. Dielectric constant and loss are measured in the temperature range 300 K to 900 K with frequency range 1 KHz to 1 MHz. To confirm the grain size, the samples are characterized by the Scanning Electron Microscope (SEM). These types of samples can be used as a high temperature semi-conducting materials.

Novel Microstructures in Microwave Sintered Silicon Nitride

1996 ◽  
Vol 430 ◽  
Author(s):  
M. E. Brito ◽  
K. Hirao ◽  
M. Toriyama ◽  
M. Hirota
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Mechanical Performance ◽  
Microwave Sintering ◽  
Preliminary Results ◽  
Nitride Ceramics ◽  
Positive Effect ◽  
Sintered Silicon

AbstractPreliminary results on microwave sintering of seeded silicon nitride show that a well defined bi-modal grain size distribution is attainable in Si3N4-Y2O3-Al2O 3-MgO sintered bodies by microwave sintering at 28 GHz of materials seeded with ß-Si3N4 particles (2 vol. %). A positive effect on the mechanical performance is anticipated for these microstructurally controlled silicon nitride ceramics

scholarly journals Porous and Nonporous Film-Shaped Magnetorheological Nanocomposites: Dielectric and Electrical Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Aref Naimzad ◽  
Yousef Hojjat ◽  
Mojtaba Ghodsi
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Volume Resistivity ◽  
Comparative Investigation ◽  
Dielectric Constants ◽  
Dielectric Losses ◽  
Iron Particles ◽  
Electrical And Dielectric Properties

This paper presents a brief experimental comparative study on electrical and dielectric properties of two sets of porous and nonporous MRNCs, each including five samples of film-shaped magnetorheological nanocomposites (MRNCs) based on room temperature vulcanized (RTV) silicone rubber and nanosized carbonyl iron particles (CIPs). The electrical and dielectric properties of porous and nonporous MRNCs were measured at five different filler concentrations. Several experiments were performed to measure the volume resistivity, dielectric constant, and dielectric loss. The MRNCs dielectric properties were analysed with respect to the parameters like frequency and CIPs loadings. The electrical conductivity was studied in terms of volume resistivity. The comparative investigation suggests the porous MRNCs for smart and light-weighted structures those benefits from a lower electrical property, dielectric losses, and dielectric constants.

α/β Phase Transformation in Porous Reaction-Bonded Silicon Nitride Ceramics

2011 ◽  
Vol 194-196 ◽  
pp. 2225-2228
Author(s):  
Jie Xu ◽  
Jun Bo Wang ◽  
Wei Hua Cui ◽  
Xiao Lei Su ◽  
Wan Cheng Zhou
Keyword(s):  
Dielectric Constant ◽  
Phase Transformation ◽  
Dielectric Properties ◽  
Silicon Nitride ◽  
Dielectric Loss ◽  
Point Defects ◽  
Nitriding Temperature ◽  
Β Phase ◽  
Nitride Ceramics ◽  
Tan Δ

Porous reaction-bonded silicon nitride ceramics with different values of α/β ratio were obtained by setting the nitriding temperature and time. The influence of α/β phase transformation on the dielectric properties of porous silicon nitride ceramics has been investigated. The results show that the α/β transformation occurs when the nitriding temperature is higher than 1400°C . The values of α/β ratio decrease with increase of nitriding temperature and time. The dielectric constant ε′ and the dielectric loss tan δ of the samples increase because of the α/β transformation, and the change of the dielectric loss is more obvious. The increase of concentrations of point defects due to the α/β transformation leads to the significant increase of the dielectric loss.

scholarly journals Preparation and studying Structural and Electrical properties of nano Co3O4

2019 ◽  
Vol 24 (6) ◽  
pp. 126
Author(s):  
Nawar Thamer Mohammed ◽  
Wasfi Mohammed Kadem
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Sol Gel ◽  
Frequency Range ◽  
Nano Powder ◽  
Structural And Electrical Properties ◽  
Electrical And Dielectric Properties ◽  
Lcr Meter

In this study (Cobalt oxide) nano powder prepared using sol-gel method with a crystallite size 22 nm By testing XRD  and by matching with card (JCPDS) files No.( 00-042-1467). Electrical and dielectric properties like (Dielectric constant, resistivity, electrical conductivity) are studied by LCR meter with frequency range from (50 Hz) to (5 MHz ). It was noted that the resistivity and dielectric constant was decreasing while electrical conductivity increased with increased  frequency    http://dx.doi.org/10.25130/tjps.24.2019.118  

scholarly journals Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

2021 ◽  
Vol 16 (2) ◽  
pp. 138-147
Author(s):  
S. A. Syrbu ◽  
M. S. Fedorov ◽  
E. A. Lapykina ◽  
V. V. Novikov
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Anisotropy ◽  
Specific Electrical Conductivity ◽  
Conductivity Anisotropy ◽  
Independent Molecules ◽  
System Properties ◽  
The Individual

Objectives. Our aim was to study the dielectric properties of the 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4’-methylaniline system and reveal how different concentrations of N-(4-n-butyloxybenzylidene)-4’-methylaniline additives affect the dielectric properties of 4-n-pentyloxybenzoic acid.Methods. System properties were investigated using polarization thermomicroscopy and dielcometry.Results. We found that dielectric anisotropy changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature one. The anisotropy of the dielectric constant of N-4-n-butoxybenzylidene-4’-methylaniline has a positive value and increases as to the system approaches the crystalline phase. The crystal structure of the 4-n-pentyloxybenzoic acid contains dimers formed by two independent molecules due to a pair of hydrogen bonds. The crystal structure of N-(4-n-butoxybenzylidene)-4’-methylaniline contains associates formed by orientational interactions of two independent molecules. 4-n-Pentyloxybenzoic acid dimers (270 nm) and associates of N-4-n-butoxybenzylidene-4’- methylaniline (250 nm) proved to have approximately the identical length. Considering the close length values of the structural units of both compounds and the dielectric anisotropy sign, we assume that the N-4-n-butoxybenzylidene-4’-methylaniline associates are incorporated into the supramolecular structure of the 4-n-pentyloxybenzoic acid. The specific electrical conductivity of the compounds under study lies between 10−7 and 10−12 S∙cm−1. The relationship between the specific electrical conductivity anisotropy and the system composition in the nematic phase at the identical reduced temperature, obtained between 100 and 1000 Hz is symbatic. However, the electrical conductivity anisotropy values of the system obtained at 1000 Hz are lower compared to those obtained at 100 Hz. At N-(4-n-butoxybenzylidene)-4’-methylaniline concentrations between 30 and 60 mol %, the electrical conductivity anisotropy values are higher than those of the individual component.Conclusions. A change in the sign of the dielectric constant anisotropy of the 4-n-pentyloxybenzoic acid during nematic subphase transitions was established. We showed that the system has the highest dielectric constant anisotropy value when components have an equal number of moles. Highest electrical conductivity anisotropy values are observed when the concentration of the N-4-n-butoxybenzylidene-4᾽-methylaniline system lies between 30 and 60 mol %. 

Study the physical, electrical and dielectric properties of calcium doped Ni–Zn ferrites

2019 ◽  
Vol 33 (12) ◽  
pp. 1950145 ◽  
Author(s):  
M. A. A. Nooman ◽  
M. N. I. Khan ◽  
S. D. Hossain ◽  
M. F. Hossain ◽  
M. A. Samad ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Spinel Phase ◽  
Nominal Composition ◽  
Thermally Activated ◽  
Composition Formula ◽  
Zn Ferrite ◽  
Mobility Of Charge Carriers ◽  
Electrical And Dielectric Properties ◽  
Calcium Doped

Calcium doped Ni–Zn ferrites having the nominal composition [Formula: see text] (x = 0, 0.1, 0.2, 0.3 and 0.4) are prepared via the conventional ceramic method at [Formula: see text] for 3 h to study their physical, electrical and dielectric properties at high frequencies which have extended their applications. The X-ray diffraction (XRD) and scanning electron microscope (SEM) have been used to characterize the microstructure and surface morphology of the prepared composition. XRD patterns reveal the formation of pure spinel phase ferrites whereas SEM micrographs display nonhomogeneous grains of polyhedral shape. The studies disclose that with increasing Ca content in spinel, the lattice parameter of the Ni–Zn ferrite increases and at the same time the grain boundary also increases. As a result of the increased boundary, the large grains could be trapped pores inside the grains which have affected the density, resistivity and dielectric constant of the sample. The DC electrical resistivity of the prepared sample decreases with the increase of Ca content. Also, the resistivity decreases with increasing the temperature. This increase in the conductivity with temperature must be regarded mainly as due to the thermally activated mobility of charge carriers, but not to a thermally activated creation of these carriers. The dielectric constant decreases with the increasing frequency following the Verway-de-Boer hopping mechanism.

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