scholarly journals Bi2O3-Modified Ceramics Based on BaTiO3 Powder Synthesized in Water Vapor

Inorganics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 8 ◽  
Author(s):  
Anastasia Kholodkova ◽  
Aleksey Smirnov ◽  
Marina Danchevskaya ◽  
Yurii Ivakin ◽  
Galina Muravieva ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Water Vapor ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Frequency Range ◽  
Batio3 Powder ◽  
Strength Determination ◽  
Water Vapor Atmosphere ◽  
Room Temperature Dielectric Constant

Bi2O3 was investigated in the role of a modifier for BaTiO3 powder synthesized in a water vapor atmosphere at 200 °C and 1.55 MPa. Modification was aimed at increasing the sinterability of the powder as well as improving the structural and dielectric properties of the obtained ceramics. The morphology and phase contents of the synthesized BaTiO3 powder were controlled by the methods of SEM and XRD. Properties of pure and Bi-doped BaTiO3 ceramics were comprehensively studied by XRD, SEM, dielectric spectroscopy, and standard approaches for density and mechanical strength determination. Doping with Bi2O3 favored BaTiO3 ceramic densification and strengthening. The room-temperature dielectric constant and the loss tangent of Bi-doped BaTiO3 were shown to stabilize within the frequency range of 20 Hz to 2 MHz compared to non-doped material. The drop of dielectric constant between room temperature and Curie point was significantly reduced after Bi2O3 addition to BaTiO3. Bi2O3 appeared to be an effective modifier for BaTiO3 ceramics produced from non-stoichiometric powder synthesized in water vapor.

DIELECTRIC PROPERTIES OF CHEMICALLY SYNTHESIZED PbTiO3 NANOCRYSTALS SUITABLE FOR HIGH FREQUENCY DEVICES

2010 ◽  
Vol 24 (23) ◽  
pp. 4547-4554
Author(s):  
K. C. VERMA ◽  
M. SINGH ◽  
N. THAKUR ◽  
N. S. NEGI
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Xrd Pattern ◽  
High Frequency Devices ◽  
Room Temperature Dielectric Constant ◽  
Transmission Scanning Electron Microscopy

PbTiO 3 (PT) nanoparticles have been prepared by chemical route using polyvinyl alcohol (PVA) as an efficient surfactant. The effect of PVA to reduce the particle's sizes of PT has been observed. X-ray diffraction (XRD) pattern shows that the PT nanoparticles are tetragonal with distortion ratio, c/a ~1.061. The average particle's size calculated from XRD and transmission/scanning electron microscopy is ~24 nm for PT powder sintered at 700°C. The nanostructured grains were also observed in PT pellet sintered at 1000°C. The dielectric properties of PT pellet have been measured from room temperature to 200°C and in the frequency range of 0.075 to 10 MHz. The values of room temperature dielectric constant and tanδ are 117 and 0.05 respectively, measured at 0.5 MHz. It is found that the dielectric constant of PT nanoparticles can be controlled up to higher frequency region of 5 MHz.

Characterization and dielectric properties of sodium fluoride doped talc

Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 551-558
Author(s):  
S. Gümüştas ◽  
K. Köseoğlu ◽  
E. E. Yalçinkaya ◽  
M. Balcan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Firing Temperature ◽  
Room Temperature ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Detailed Characterization ◽  
Circuit Element

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.

Effect of Sintering Parameters and Ta2O5 Doping on the Microstructure and Dielectric Properties of BaTiO3 Based Ceramics

2014 ◽  
Vol 608 ◽  
pp. 247-252 ◽  
Author(s):  
Md. Fakhrul Islam ◽  
Rubayyat Mahbub ◽  
Adnan Mousharraf
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Tantalum Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Techniques ◽  
Titanate Ceramics ◽  
The Relationship ◽  
Room Temperature Dielectric Constant

The main focus of the research was to correlate the composition and sintering parameters with the microstructure and dielectric properties of Ta2O5 (Tantalum Oxide) doped BaTiO3 (Barium Titanate) ceramics. Ta2O5 was doped at three different percentages viz. 0.5, 1.0 and 1.5 mole%. The doped samples were then sintered using both single and double stage sintering techniques. Thereafter field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) techniques were used to examine the structure of the samples with particular focus on the incorporation of Ta5+ions into the BaTiO3 crystal lattice. Finally, the dielectric properties were analyzed using impedence analyzer and the relationship between the properties and structure of doped BaTiO3 was established. From the research, it can be stated that double stage sintering yielded best dielectric properties. The best stable value of room temperature dielectric constant (k) of 19000 was obtained for 1.5mole % Ta2O5 doped BaTiO3 sample, sintered at 1320°C for 0 hour and 1280°C for 6 hours due to the combination of high percent theoretical density (%TD) and optimum grain size. At a temperature range of 30°C to 60°C, this combination of composition and sintering parameters yielded dielectric constant in the range of 18000-19000.

THE DIELECTRIC PROPERTIES OF SELECTED BASALTS

Geophysics ◽  
1973 ◽  
Vol 38 (1) ◽  
pp. 135-139 ◽  
Author(s):  
W. Hansen ◽  
W. R. Sill ◽  
S. H. Ward
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
Frequency Dispersion ◽  
Nitrogen Atmosphere ◽  
Frequency Range ◽  
Dielectric Constant And Loss ◽  
Identical Composition ◽  
Titanium Compounds

Basaltic samples of known chemical composition were measured for dielectric constant and loss tangent in the frequency range 100 hz to 50 Mhz. All samples were prepared and measured by a contact substitution method in a dry nitrogen atmosphere at room temperature. The measurements indicated a general spectrum of dielectric constant with a range of 10–65 at 100 hz to 7–15 at 50 Mhz with frequency dispersion observed to be minimal above 1 Mhz. The loss tangent decreases from a range .2–.9 at 100 hz to a range .02–.15 at 100 khz. A finer‐grained sample was observed to have higher dielectric properties below 1 Mhz than a coarser‐grained sample of identical composition. A qualitative and subsequent quantitative study of possible compositional effects indicated that iron‐titanium compounds may be responsible for observed variations in the dielectric spectra of typical basalts.

Preparation and Characterization of CaCu3Ti4O12 Ceramics by Cold Isostatic Press Forming

2008 ◽  
Vol 368-372 ◽  
pp. 123-125
Author(s):  
Jie Li ◽  
Hao Xue ◽  
Zhao Xian Xiong
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Frequency Range ◽  
Cold Isostatic Press ◽  
Temperature Range ◽  
Press Forming ◽  
Conventional Sintering ◽  
Sintering Method

CaCu3Ti4O12 (CCTO) ceramics were prepared by cold isostatic press (CIP) forming combined with the conventional sintering method. The effects of calcining temperature on properties of CCTO ceramics were investigated. The dielectric properties as the function of temperature at typical frequencies were measured in the temperature range from 243 to 363 K. In addition, the dielectric properties and complex impedances at room temperature were analyzed in a frequency range from 20 Hz to 106 Hz. The results showed that CCTO ceramics with dielectric constant higher than 104 were obtained. Compared with the dry press forming, CCTO ceramics prepared by CIP had more homogeneous grains, less porosity and better dielectric properties.

Dielectric Properties of SiAlON Ceramics

2008 ◽  
Vol 403 ◽  
pp. 125-128 ◽  
Author(s):  
Do Kyung Kim ◽  
Ha Neul Kim ◽  
Young Hoon Seong ◽  
Seung Soo Baek ◽  
Eul Son Kang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Microwave Frequency ◽  
Tangent Loss ◽  
Hot Press ◽  
Frequency Range ◽  
Cationic Species ◽  
Press Method ◽  
Resonator Method

The dielectric properties of -SiAlON and various cations doped -SiAlON bulk ceramics prepared by a hot-press method were investigated. The dielectric properties (dielectric constant and tangent loss) were characterized by a post-resonator method (Hakki-Coleman method) at room temperature in the microwave frequency range. The effect of z-values about -SiAlON was examined, and also the effects of various interstitial cations on dielectric properties of -SiAlON were studied. Dielectric properties of -SiAlON were compared with those of Si3N4 and -SiAlON and their relationship between the dielectric properties and the cationic species of SiAlON were discussed.

Morphology and Dielectric Properties of Boron-doped BaTiO3

2013 ◽  
Vol 32 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Zhuo Qun Zheng ◽  
Xiao Ping Zhou
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Dielectric Strength ◽  
Optimum Composition ◽  
Boron Doped ◽  
Boron Dopant ◽  
Room Temperature Dielectric Constant

AbstractBoron-doped BaTiO3 precurors (BaTi1−xB2xO3+X) were prepared via the glycol-glycerol complexes of boron, titanium (IV), and barium. With optimum composition, ceramics with dielectric properties comparable to those of pristine BaTiO3 ceramic sintered at 1300°C can be obtained after sintered at temperature less than 900°C (room-temperature dielectric constant ∼4000, dielectric strength ∼7.0 kV/mm). The appreciable decrease in sintering temperature is attributable to (a) addition of boron dopant as substitute of titamium rather than to stochiometric BaTiO3, and (b) application of glycol-glycerol solvents/ligands in the synthesis of precursors, which guarantees the compositional homogenization of the final ceramics.

Influence of CuO Additive on Density and Dielectric Properties of Ba(Zr0.05Ti0.95)O3 Ceramics Prepared by Molten Salt Method

2020 ◽  
Vol 302 ◽  
pp. 115-121
Author(s):  
Chompoonuch Warangkanagool
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Molten Salt ◽  
Room Temperature ◽  
Molten Salt Method ◽  
Distilled Water ◽  
Fluid Medium ◽  
Lcr Meter ◽  
Room Temperature Dielectric Constant

In this research, the Ba(Zr0.05Ti0.95)O3 powders were prepared by molten salt method. The powders were calcined at 600-1100°C for 3 h with heating rate of 5°C/min. The BZT powders were synthesized by molten salt method to reduce the calcination temperature by up to 300°C. The sintering procedure was carried out at 1250°C for 2 h with a heating/cooling rate of 5°C/min. Phase formation and microstructure were examined by XRD and SEM, respectively. The influence of the CuO additive on density and dielectric properties were investigated. The density of the sintered samples was measured by Archimedes method with distilled water as the fluid medium. Dielectric properties were examined by LCR meter. The BZT+2.0 mol% CuO ceramic sintered at 1250°C showed the highest density of 5.76 g/cm3, and the room temperature dielectric constant and dielectric loss at 1 kHz were 2687 and 0.01, respectively.

Effect of Sintering Time on Dielectric Properties of Barium Titanate and Nb Doped Barium Titanate

2016 ◽  
Vol 860 ◽  
pp. 129-133 ◽  
Author(s):  
M.K. Rahman ◽  
M.F. Hossain ◽  
Kazi Mohammad Shorowordi ◽  
M.A. Matin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Room Temperature ◽  
Niobium Oxide ◽  
Dielectric Material ◽  
Multilayer Ceramic Capacitors ◽  
Sintering Time ◽  
High K ◽  
Room Temperature Dielectric Constant

Barium titanate (BaTiO3) with its perovskite structure is a promising dielectric material for many applications such as transducers, actuators, high-k dielectrics and multilayer ceramic capacitors (MLCC). In this study, we have investigated the effect of sintering time on dielectric properties of BaTiO3 and Nb-doped BaTiO3. BaTiO3 was doped with 0.3 mol % niobium oxide (Nb2O5). At first, nanosized pure BaTiO3 and Nb2O5 doped BaTiO3 were milled, dried and pressed into pellets to prepare green samples. Then, the samples were sintered at 1275°C for different time periods ranging from 2 to 5 hrs. Single stage sintering was adopted for the densification of prepared samples. Microstructure of the sintered samples was investigated employing Field-emission scanning electron microscope (FESEM). Dielectric properties of the samples were measured using an impedance analyzer. Finally, a correlation was established between the dielectric properties of the sintered samples and their microstructure. Nb has shown to provide strong inhibiting effect after sintering the samples in the range of 2 to 5 hours at 1275°C thereby, resulted in higher dielectric properties of doped BaTiO3 ceramics compared to that of pure BaTiO3. The best room temperature dielectric constant of 7200 was obtained for Nb doped BaTiO3 sintered at 1275°C for five hours. Such improved dielectric constant is attributed to the optimum grain size of about 1 micron at this sintering temperature.

Sintering and Dielectric Properties of SrTiO3-based Ceramics

2012 ◽  
Vol 1397 ◽  
Author(s):  
Juan Li ◽  
Dengren Jin ◽  
Lixin Zhou ◽  
Jinrong Cheng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Precursor Solution ◽  
Particle Sizes ◽  
Low Dielectric ◽  
Different Temperatures ◽  
High Dielectric ◽  
Room Temperature Dielectric Constant

ABSTRACTHigh dielectric tunability, low dielectric loss tangent and appropriate level of dielectric constant are the basic requirements for applications as electrically tunable dielectric microwave devices. In our experiments, the SrTiO3 green compacts made of the powder mixtures with various particle sizes were infiltrated with a BaTiO3 precursor solution and sintered at different temperatures between 1280 and 1350 ºC for 2 hours and 1350 ºC for 6 hours. The sintering, microstructural and dielectric properties were investigated. Results showed that the relative density of SrTiO3 ceramics could reached 93% when sintered at 1280 ºC for 2 hours. When sintered for 6 hours at 1350 °C, the room temperature dielectric constant of SrTiO3 reaches 900 at a frequency of 1MHz. It has only weak temperature dependence between 100 and 500K. The reason of the low sintering temperature for the dense SrTiO3 ceramics and the effects of sintering scheme on the dielectric properties from 100 K to 500 K are discussed in this paper.

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