Influence of Ti content and sintering temperature on dielectric properties of Bi4Ti3O12 ceramics

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744057 ◽  
Author(s):  
Yong Chen ◽  
Zhaozhi Li ◽  
Huyin Su ◽  
Simin Xue ◽  
Mengyun Bian ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Curie Temperature ◽  
Relative Permittivity ◽  
Dielectric Material ◽  
Perovskite Phase ◽  
Layered Perovskite ◽  
Microwave Ceramics ◽  
Ti Content

An ultra-broad working temperature dielectric material, Bi4Ti[Formula: see text]O[Formula: see text]([Formula: see text] = 2.96, 2.98, 3.0, 3.02 and 3.04), prepared by a conventional mixed oxide route was investigated which is supposed to replace lead-containing ceramics for its outstanding dielectric properties. Microstructure and dielectric properties of well-sintered samples (at 1040[Formula: see text]C, 1060[Formula: see text]C, 1080[Formula: see text]C, 1100[Formula: see text]C and 1120[Formula: see text]C) were studied. X-ray diffraction analysis indicated that the new material was in a single Bi-layered perovskite phase. The dielectric constant and dielectric loss at different frequencies (10, 100 and 1000 kHz) were measured at 1100[Formula: see text]C. With the increasing frequency, the dielectric constant decreased and the dielectric loss was almost unchanged. While at 100 kHz, there is the highest relative permittivity ([Formula: see text]) of 2822.8 and the lowest dielectric loss of 0.0040 ([Formula: see text] = 2.98), the Curie temperature ([Formula: see text]) is 668.9[Formula: see text]C. At the frequency of 1 MHz, the highest relative permittivity ([Formula: see text]) is 1115.8 when Ti content is 3.02, and the Curie temperature is 672.2[Formula: see text]C. SEM can explain the results of the dielectric spectrum at different Ti content and sintering temperatures. [Formula: see text] plots show that Bi4Ti3O[Formula: see text] ceramics are a kind of dielectrics. Since it possesses large dielectric constant, low dielectric loss and stable temperature character, this material shows promising applications for the ultra-broad temperature range components, such as high-temperature multilayer ceramic capacitors and microwave ceramics.

Dielectric Properties Enhancement in Polybenzoxazine Composite at Multi-Frequency Range

2008 ◽  
Vol 55-57 ◽  
pp. 105-108 ◽  
Author(s):  
Nidchakarn Krueson ◽  
H. Manuspiya ◽  
Pitak Laoratanakul ◽  
H. Ishida
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Barium Strontium Titanate ◽  
Dielectric Material ◽  
Dielectric Constants ◽  
Frequency Range ◽  
Barium Strontium ◽  
Silane Coupling ◽  
Constant Improvement

This research proposed a novel nano barium strontium titanate (BST) powder- polybenzoxazine composite as a new dielectric material. In this work, the dielectric properties of a surface-treated BST powder-polybenzoxazine composite were studied. The surface of the BST powders were modified by using three different chemicals: 3-aminopropyl-trimethoxysilane, benzoxazine monomer and phthalocyanine. The distribution of the BST powders in the polybenzoxazine matrix was observed by SEM. The dielectric constants of the composites with a function of frequency (1 kHz–10 MHz) were investigated. It was found that the composites with modified BST powders showed good distribution in the polybenzoxazine matrix, and the dielectric constants were also much enhanced than those with untreated BST powders. In comparisons among the three modification methods, the composite with the silane coupling modified BST powder showed significantly in dielectric constant improvement while the composite with the benzoxazine and phthalocyanine modified BST powders displayed lower dielectric loss due to the modified powder dispersed well in the polybenzoxazine matrix.

Sn-doped BaO–TiO2–ZnO Microwave Ceramics

2002 ◽  
Vol 17 (6) ◽  
pp. 1550-1552 ◽  
Author(s):  
Wu Shunhua ◽  
Wang Guoqing ◽  
Zhao Yushuang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Temperature Coefficient ◽  
Sintering Temperature ◽  
Volume Resistivity ◽  
Ceramic Materials ◽  
Microwave Ceramics ◽  
Microwave Ceramic ◽  
Tan Δ

Sn-doped BaO–TiO2–ZnO (BTZ) microwave ceramic materials were investigated as a function of SnO2 content. Addition of a small amount of SnO2 (0.01–0.06 wt%) lowered the sintering temperature of the system to 1160 °C and also greatly reduced the dielectric loss (tan δ), which is closely related to the insulation resistivity. The Sn-doped BTZ materials were found to have excellent dielectric properties at 1 GHz with dielectric constant Ε ≈tangent tan δ ≤ 1 × 10−4, temperature coefficient of dielectric constant, αΕ = 0 ± 30 ppm/°C, and volume resistivity ρv ≥ 1013 ω cm.

Dielectric Properties of Cr2O3 Doped (Ba,Sr,Ca)TiO3 Ceramics for Tunable Microwave Devices

2006 ◽  
Vol 966 ◽  
Author(s):  
Bing Qin ◽  
Dengren Jin ◽  
Jinrong Chen ◽  
Zhongyan Meng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Curie Temperature ◽  
Mixed Oxide ◽  
Dopant Concentration ◽  
Homogeneous Structure ◽  
Microwave Devices ◽  
Thermal Stabilities ◽  
Dielectric Constant And Loss

ABSTRACTCr2O3-doped (Ba0.55Sr0.4Ca0.05)TiO3 ceramics were fabricated by the mixed-oxide method. Their dielectric properties were investigated with the variation of Cr3+ doping concentrations (0∼2.0mol%). All the BSCT specimens owned dense and homogeneous structure. Doping of Cr3+ could reduce the Curie temperature and their dielectric constant peak values, and improve the thermal stabilities of their dielectric properties. Both the dielectric constant and dielectric loss of the BSCT ceramics were reduced by doping Cr ions when the dopant concentration was lower than 1.5mol%. 1.0mol% Cr-doped BSCT specimens are expected to be the candidate materials for microwave tunable devices, whose tunability, dielectric constant and loss were 16.1%, 2700 and 0.24% respectively.

Electrical Properties of Bismuth-Layered Structural CaxSr2-xBi4Ti5O18 Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 282-285 ◽  
Author(s):  
Su Hua Fan ◽  
Feng Qing Zhang ◽  
Q.D. Che ◽  
R. Yu ◽  
W. Hu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Remnant Polarization ◽  
Single Phase ◽  
Ferroelectric Properties ◽  
Secondary Phase ◽  
Ferroelectric Ceramics ◽  
Layered Perovskite

Effects of amount of Ca on crystal structure, microstructure, ferroelectric properties, and dielectric properties of the CaxSr2-xBi4Ti5O18 (CSBTi-x) ferroelectric ceramics were investigated. The results show that single-phase layered perovskite ferroelectrics were obtained and no appreciable secondary phase was found.Ca-doping results in a notable enlargement of remnant polarization 2Pr. The 2Pr of CSBT-0.15 reaches a large value, the remnant polarization 2Pr and coercive field 2Ec were 18.1µC/cm2 and 120.2kV/cm, respectively. Dielectric constant and dielectric loss of CSBT-0.15 was also measured, showing dielectric constant εr=199~194 and dielectric loss tanδ=0.02~0.014 over the range of 100 kHz~1MHz, respectively.

Skin–core structured fluorinated MWCNTs: a nanofiller towards a broadband dielectric material with a high dielectric constant and low dielectric loss

2018 ◽  
Vol 6 (9) ◽  
pp. 2370-2378 ◽  
Author(s):  
Yang Liu ◽  
Cheng Zhang ◽  
Benyuan Huang ◽  
Xu Wang ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Epoxy Composite ◽  
Low Dielectric ◽  
High Dielectric

A novel skin–core structured fluorinated MWCNT nanofiller was prepared to fabricate epoxy composite with broadband high dielectric constant and low dielectric loss.

Microstructure and Microwave Dielectric Properties of BaTi4O9 Ceramics Derived from a Sol-Gel Precursor

2011 ◽  
Vol 326 ◽  
pp. 127-130
Author(s):  
Xian Li Huang ◽  
Fu Ping Wang ◽  
Ying Song
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Microwave Dielectric Properties ◽  
Sintering Process ◽  
Temperature Coefficients ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Quality Factor Q

In the present work, the microstructure and microwave dielectric properties of BaTi4O9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (εr), quality factor (Q×f) and the temperature coefficients (τf) of the BaTi4O9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti3+ was proposed to be the cause of dielectric loss.

Preparation and Dielectric Properties of 1-3 La Modified PZT/IPN Piezoelectric Composites

2010 ◽  
Vol 105-106 ◽  
pp. 355-358 ◽  
Author(s):  
Z.L. Zhu ◽  
Dong Yan Tang ◽  
X.H. Zhang ◽  
Y.J. Qiao
Keyword(s):  
Heat Treatment ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Lead Zirconate Titanate ◽  
Polymer Network ◽  
Lead Zirconate ◽  
Interpenetrating Polymer Network ◽  
Ceramic Fibers ◽  
Piezoelectric Composites

To prevent the potential cracking of gel fibers, La modified lead zirconate titanate (PLZT) ceramic fibers with diameter within 50µm were achieved by embedding into PLZT powders during the heat treatment. Then the 1-3 PLZT fiber/interpenetrating polymer network (IPN) piezoelectric composites were prepared by casting the IPN precursors onto the well aligned ceramic fibers. The influences of the heating temperatures and La amounts on the dielectric constant, dielectric loss with frequencies and piezoelectric constant of PLZT were investigated in detail. The morphologies of fibers and composites were observed by biological microscope. And also, the dielectric constant of PLZT fibers and PLZT fiber/IPN piezoelectric composites were detected.

Microwave Nondestructive Sensing of Moisture Content and Water Activity of Almonds

2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Bulk Density ◽  
Water Activity ◽  
Free Space ◽  
Loss Factor ◽  
Dielectric Loss Factor ◽  
List Type

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.

Analysis of the Characteristics on Dielectric Barrier Discharges Depending on the Relative Permittivity and Frequency

2018 ◽  
Vol 875 ◽  
pp. 113-116 ◽  
Author(s):  
Don Kyu Lee
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Relative Permittivity ◽  
Discharge Voltage ◽  
Frequency Region ◽  
Dielectric Barrier Discharges ◽  
Dielectric Barrier ◽  
Dielectric Layers ◽  
Green Sheet ◽  
Barrier Discharges

Various studies are being conducted on the application of DBD (Dielectric barrier discharges). The internal dielectric has a very important characteristic on DBD, thus we analyze of the characteristics on dielectric barrier discharges depending on the relative permittivity and frequency. Through simulation, the discharge voltage was calculated based on relative permittivity and frequency of real used dielectrics (Green sheet, Down dielectric, white dielectric). We investigate that increased relative permittivity and fast frequency occur the decrease of the firing voltage. Also, we investigate the frequency dependence of the dielectric constant and dielectric loss of dielectric layers measured at a frequency region of 100Hz to 10MHz. In a condition of drive within 1MHz, with regard to the change of real and imaginary part according to frequency, it has quite stable dielectric constant in the condition of drive within 1MHz.

Synthesis and Dielectric Properties of [(K0.5Na0.5)0.935Li0.065]NbO3 Added with Mn for Piezoelectric Ceramic

2016 ◽  
Vol 675-676 ◽  
pp. 635-638
Author(s):  
Jukkrit Kongphimai ◽  
Hassakorn Wattanasarn ◽  
Tosawat Seetawan
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Physical Properties ◽  
Crystallite Size ◽  
Piezoelectric Ceramic ◽  
Theoretical Density ◽  
Milling Method ◽  
Xrd Patterns

[(K0.5Na0.5 )0.935Li0.065]NbO3–Mn ceramics (Mn = 0, 1.50 and 3 mol %) (KNNL–Mn) were synthesized and measured dielectric properties. Which the K2CO3, Na2CO3, Li2CO3, Nb2O5 and MnO2 (0, 1.5, 3 mol%) were mixed by ball milling method and calcined powders at 1,073 K for 4 h and the sintered at 1,343 K for 2 h in air. The crystal structure was analyzed by XRD technique, the crystallite size was identified by Scherrer’s equation and calculated the theoretical density. It was found that, the XRD patterns of the KNNL–Mn ceramics added with Mn contents was indicated the tetragonal structure and. the crystallite size of Mn = 0, 1.50 and 3 mol% about 32 nm, 34 nm and 57 nm, respectively. The physical properties of the KNNL–Mn ceramics was found that the maximum theoretical density of 90.79 % for Mn = 1.50 mol%. The dielectric constant was found to be maximum of 909.77 and dielectric loss of 0.48 for Mn = 3 mol%.

Sign in / Sign up

Export Citation Format

Share Document