Grain Size Dependence of the Microstructure and Dielectric Properties of Potassium Niobate-Barium Titanate Ceramics

2013 ◽  
Vol 566 ◽  
pp. 34-37
Author(s):  
Kenta Yamashita ◽  
Ichiro Fujii ◽  
Kouichi Nakashima ◽  
Nobuhiro Kumada ◽  
Yoshihiro Kuroiwa ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Size Dependence ◽  
Potassium Niobate ◽  
Titanate Ceramics

In this study, 0.8 KNbO3(KN) -0.2 BaTiO3(BT) ceramics were prepared using KN powder with the diameter of 100 nm and BT powders with the diameter of 100, 300, or 500 nm. The relative densities were more than 96 % of the theoretical densities of the samples. The dielectric constant of the samples was temperature-stable at temperatures between-50 and 300 °C and it was found that the dielectric constant of the 0.8KN-0.2BT ceramics increased as the BT diameter increased.

Preparation of Potassium Niobate–Barium Titanate Ceramics Using Well-Dispersed Nanoparticles and their Dielectric Properties

2011 ◽  
Vol 485 ◽  
pp. 39-42 ◽  
Author(s):  
Kenta Yamashita ◽  
Shigehito Shimizu ◽  
Ichiro Fujii ◽  
Kouichi Nakashima ◽  
Nobuhiro Kumada ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Potassium Niobate ◽  
Conventional Sintering ◽  
Titanate Ceramics ◽  
Sintering Method

ANbO3– BaTiO3(A=K, Na, or K0.5Na0.5) system ceramics were prepared using a conventional sintering method, and their dielectric properties were investigated. It was found that the dielectric constant of KNbO3-BaTiO3and (K0.5Na0.5) NbO3- BaTiO3system ceramics did not strongly depend on temperature between 20 and 400 °C, making them useful for capacitor application.

Broadband Dielectric Spectroscopy Analysis of Dielectric Properties of Barium Titanate Ceramics

2013 ◽  
Vol 744 ◽  
pp. 323-328 ◽  
Author(s):  
Jie Yang ◽  
Xiang Yun Deng ◽  
Jian Bao Li ◽  
Qiang Cai ◽  
Hai Tao Zhang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Barium Titanate ◽  
Relaxation Model ◽  
Debye Relaxation ◽  
Broadband Dielectric Spectroscopy ◽  
Function Fitting ◽  
Loss Experience ◽  
Titanate Ceramics

The complex dielectric behaviors of ferroelectric barium titanate (BT) ceramics were investigated. The dielectric properties were studied as a function of temperature and frequency using broadband dielectric spectrometer. The results show that the maximum value of dielectric constant occurs at 500nm BT ceramics, which is approximately 7,500; the dielectric loss is lower than 0.03 with the temperature varying from 225 K to 450 K. Dielectric constant and dielectric loss experience three dielectric peaks corresponding to rhombohedral to orthorhombic, tetragonal and cubic transitions. With the frequency ranges from 1 MHz to 1 GHz, the dielectric relaxation is apparently present. The relaxation process obeys Cole-Cole relaxation model at high temperature and conforms to Debye relaxation model when the temperature far lower than Curie temperature. The relaxation time is the order magnitude of ~10-9s obtained by Havriliak-Negami function fitting, which is very consistent with theoretical calculation.

scholarly journals Dependence of the dielectric properties of barium titanate ceramics and a composite based on it on the sintering temperature

2021 ◽  
Vol 24 (1) ◽  
pp. 40-47
Author(s):  
O. V. Malyshkina ◽  
A. I. Ivanova ◽  
Gr. S. Shishkov ◽  
A. A. Martyanov
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Barium Ferrite ◽  
Sintering Temperature ◽  
Pyroelectric Coefficient ◽  
Ceramic Samples ◽  
Barium Titanate Ceramic ◽  
Titanate Ceramics ◽  
Composite Samples

In this paper, we compare the structure and dielectric properties of the samples of barium titanate ceramics that have been sintered at temperatures of 1100, 1150, 1200, 1250 and 1350 °C and dielectric characteristics of the samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%). It is shown that only samples sintered at the temperature of 1250 and 1350 °C have polarization sufficient for the existence of the piezoelectric effect. For the same samples, the pyroelectric coefficient and reversal polarization significantly exceed those for samples sintered at lower temperatures. Analysis of the samples structure confirmed the dependence of the dielectric properties of the barium titanate ceramics on the grain size and, as a consequence, on the sintering temperature. Based on the studies carried out, the optimal temperature (1250 °С) for obtaining composite samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%) was selected. The temperature dependence of the dielectric constant for the composite samples based on barium ferrite — barium titanate with a sintering temperature of 1250 °C is similar to the dependence for the BaTiO3 ceramic samples sintered at 1350 °C. At room temperatures, the permittivity of the composite samples is also significantly higher than that of the barium titanate ceramic samples obtained at the same sintering temperatures. The addition of barium ferrite to the barium titanate not only increased the permittivity of the composite, but also led to a diffusing of the ferroelectric phase transition and a shift in the temperature of the maximum of the dielectric constant by 10 degrees towards high temperatures.

Grain size dependence of the rayleigh coefficients in barium titanate ceramics

2000 ◽  
Vol 240 (1) ◽  
pp. 1317-1324 ◽  
Author(s):  
Liliana Mitoseriu ◽  
Vasile Tura ◽  
Dan Ricinschi ◽  
Catalin Harnagea
Keyword(s):  
Grain Size ◽  
Barium Titanate ◽  
Size Dependence ◽  
Titanate Ceramics

scholarly journals Microstructure and dielectric properties of La2O3 doped Ti-rich barium strontium titanate ceramics for capacitor applications

2018 ◽  
Vol 35 (4) ◽  
pp. 806-815 ◽  
Author(s):  
Chen Zhang ◽  
Fangxu Chen ◽  
Zhixin Ling ◽  
Gang Jian ◽  
Yuanliang Li
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Relative Dielectric Constant ◽  
Unit Cell ◽  
Doping Content ◽  
Barium Strontium ◽  
Titanate Ceramics

Abstract Microstructure and dielectric properties of La2O3 doped Ti-rich barium strontium titanate ceramics, prepared by solid state method, were investigated with non-stoichiometric level and various La2O3 content, using XRD, SEM and LCR measuring system. With an increase of non-stoichiometric level, the unit cell volumes of perovskite lattices for the single phase Ti-rich barium strontium titanate ceramics increased due to the decreasing A site vacancy concentration V″A. The unit cell volume increased and then decreased slightly with the increasing La2O3 content. Relatively high non-stoichiometric level and high La2O3 content in Ti-rich barium strontium titanate ceramics contributed to the decreased average grain size as well as fine grain size distribution, which correspondingly improved the temperature stability of the relative dielectric constant. The relative dielectric constant єrRT, dielectric loss tanδRT and the maximum relative dielectric constant єrmax decreased and then increased with the increasing non-stoichiometric level. With the increase of La2O3 doping content, the relative dielectric constant єrRT increased initially and then decreased. The maximum relative dielectric constant єrmax can be increased by applying low doping content of La2O3 in Ti-rich barium strontium titanate ceramics due to the increased spontaneous polarization.

Microstructure Evolution and Dielectric Properties of Nb/Mn and Dy/Mn Doped Barium Titanate Ceramics

2006 ◽  
Vol 518 ◽  
pp. 229-234 ◽  
Author(s):  
Ljiljana Živković ◽  
V. Paunović ◽  
M. Miljković ◽  
Momcilo M. Ristić
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Solid State ◽  
High Dielectric Constant ◽  
Dopant Content ◽  
Doped Barium Titanate ◽  
High Dielectric ◽  
Titanate Ceramics ◽  
Mn Doped

Nb/Mn and Dy/Mn codoped BaTiO3 specimens, prepared by conventional solid-state procedure, were investigated regarding their microstructural and dielectric properties. The powders were doped with Nb2O5 and Dy2O3 with an amount of 0.1, 0.5 and 1.0 at% of dopants ions. The MnO content of 0.05 at% Mn was the same in both types of samples. The specimens were sintered in air at 1320 and 1350 °C for two hours. Microstructural and compositional studies were done by SEM equipped with EDS. In low doped BaTiO3 the grain size is around 1-3 μm, while in ceramics with high dopant content (1.0 at%) the grain size distribution was in the range of 3-10 μm. High dielectric constant is associated with small-grained microstructure, being 5000 for Dy-doped and 6500 for Nb-doped BaTiO3 sintered at 1350 °C. The specimens with low dopant content demonstrate the Curie-Weiss behavior in a paraelectric regime. A nearly flat permittivity response with temperature was obtained for specimens with 0.5 and 1.0 at% Dy content. Loss tangents were in the range of 0.03 - 0.32.

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