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.

Low Temperature Sintering Ba3Ti5Nb6O28 Ceramics with Tunable Temperature Coefficient of Dielectric Constant

2008 ◽  
Vol 368-372 ◽  
pp. 170-172 ◽  
Author(s):  
Dong Guo ◽  
Zhi Yuan Ling ◽  
Xing Hu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Low Temperature ◽  
Temperature Coefficient ◽  
Sintering Temperature ◽  
Low Temperature Sintering

A middle permittivity dielectrics with the tunable temperature coefficient of dielectric constant (τε) in the BaO-TiO2-Nb2O5 system, Ba3Ti5Nb6O28, has been synthesized and characterized. The dielectric properties of Ba3Ti5Nb6O28 measured at 1MHz are as follows: dielectric constant (εr) ~38, dielectric loss (tanδ)<0.0002, temperature coefficient of dielectric constant (τε)~-22ppm/°C. The Ba3Ti5Nb6O28 phase satisfies the requirements of NP0 (MLCC) dielectrics, but the sintering temperature of the Ba3Ti5Nb6O28 phase (1250~1300°C) is too high to be co-fired with Ag or Cu electrodes. To lower the sintering temperature, an appropriate amount of ZnO-B2O3 frit (5~7wt.%) was added to the Ba3Ti5Nb6O28 phase and dense ceramics were obtained at the sintering temperature lower than 1000°C. Furthermore, the CaNb2O6 phase with the positive τε of 65ppm/°C was incorporated into the Ba3Ti5Nb6O28 phase to adjust the temperature coefficient of dielectric constant from negative to positive(-22~30ppm/°C). Near zero τε ceramics with high εr (38) and low tanδ (0.0002) were obtained at the composition of Ba3Ti5Nb6O28/ CaNb2O6/ ZB frit=76:17:7 wt.%.

Effects of Co2O3 on the Dielectric Properties of Mg2TiO4- Mg2SiO4 Microwave Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 13-14
Author(s):  
Ling Xia Li ◽  
Xiao Dong Sun ◽  
Xia Wan Wu
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Ceramic Material ◽  
Sintering Temperature ◽  
Q Value ◽  
Microwave Ceramics ◽  
High Q ◽  
Microwave Ceramic ◽  
Quality Factor Q ◽  
Low Permittivity

Effect of Co2O3 on microstructure and dielectric properties of Mg2TiO4-Mg2SiO4 microwave ceramic with low permittivity and high Q value was studied. Co2O3 acts and results in decreasing of the sintering temperature and densification of the ceramic material. As a result, the dielectric loss decreases and quality factor Q increases. Mg2+ is replaced partially with Co2+ in Mg2TiO4 to form (Mg,Co)2TiO4. It is demonstrated that the system with 2.4 wt% Co2O3 possesses better dielectric properties.

Preparation and Investigation on Properties of the MgTiO3-CaTiO3 Microwave Ceramic Materials

2014 ◽  
Vol 997 ◽  
pp. 419-423 ◽  
Author(s):  
Li Dong ◽  
Gui Xia Dong ◽  
Yuan Yuan Li ◽  
Xi Zhang
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Volume Density ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Solid Reaction ◽  
Reaction Method ◽  
Microwave Ceramic ◽  
Sintering Method

The MgTiO3 and CaTiO3 powders were synthesized by solid reaction method, and MgTiO3-CaTiO3 ceramic was prepared using pressureless sintering method. The experiment prepared MgTiO3-CaTiO3 ceramics with high compactness and stable permittivity by the way of changing the mole ratio of MgTiO3 and CaTiO3 to investigate the effect of CaTiO3 on the performances of MgTiO3-CaTiO3 ceramics. The results show that Mg2TiO4 formed as second phase during sintering. Volume density and dielectric constant of MgTiO3-CaTiO3 ceramics with 10%mol CaTiO3 reach maximum of 3.612g/cm3 and 17.8, respectively, under 1460°C sintering temperature. And for the MgTiO3-CaTiO3 ceramics with 5%mol CaTiO3 the maximum values which are 3.5g/cm3 and 16.6, respectively, appear under 1510°C sintering temperature.

Effects of Mg2SiO4 Addition on the Microstructure and Dielectric Properties of MgTiO3-CaTiO3 Ceramics

2013 ◽  
Vol 675 ◽  
pp. 200-204
Author(s):  
Fei Shi ◽  
Peng Cheng Du ◽  
Jing Xiao Liu ◽  
Ji Wei Wu ◽  
De Qing Chen ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Dielectric Loss ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Composite Ceramics ◽  
Reaction Method ◽  
Dielectric Ceramics

The Mg2SiO4-MgTiO3-CaTiO3 composite dielectric ceramics with different Mg2SiO4 addition amounts were prepared by solid state reaction method. The effects of Mg2SiO4 addition amounts on the microstructure and dielectric properties as well as sintering temperature of xMg2SiO4-(0.95-x)MgTiO3-0.05CaTiO3 (abbreviated as xMSTC, 0.25≦x≦0.75) composite ceramics were investigated. The results indicated that the sintering temperature of MgTiO3-CaTiO3 based ceramics with Mg2SiO4 addition could be lowered effectively to 1320~1340°C, and the dielectric constant decreased and dielectric loss increased gradually with the increase of Mg2SiO4 content. The 0.45MSTC ceramics containing 45 wt% Mg2SiO4 and sintered at 1340°C showed desirable dielectric properties with dielectric constant εr=13.3，dielectric loss tanδ=4.5×10-4 and temperature coefficient of relative permittivity τε =10 ppm/°C.

Dielectric Properties of Li-Doped CaCu3Ti4O12 Ceramics

2011 ◽  
Vol 687 ◽  
pp. 251-256 ◽  
Author(s):  
Ying He ◽  
Huai Wu Zhang ◽  
Yuan Xun Li ◽  
Wei Wei Ling ◽  
Yun Yan Wang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Secondary Phase ◽  
Doping Amount ◽  
Spectroscopy Analysis ◽  
Low Dielectric ◽  
Tan Δ ◽  
High Dielectric ◽  
Impedance Spectroscopy Analysis

CaCu3Ti4O12 ceramics doped with 0-2.0 wt% Li2CO3 were prepared by the solid-state reaction, and their electric and dielectric properties were investigated. It is found that these ceramics had the properties of high dielectric constant and comparatively low dielectric loss. At the doping amount of 0.5 wt%, the dielectric constant is kept to be 105 with weak frequency dependence below 105 Hz, and its loss tangent (tan δ) is suppressed below 0.1 between 300 Hz-5 kHz (with the minimum value of 0.06 at 1 kHz from 218 K to 338 K). The impedance spectroscopy analysis confirms that the decrease of dielectric loss is mainly due to the increase of resistance in the grain boundary, which may be related to the influence of Ti4O7 secondary phase. Our result indicates that doping Li2CO3 is an efficient method to optimize the dielectric properties of CaCu3Ti4O12.

Study of Ac Conductivity and Dielectric Properties of PMMA with Fe2O3+ Al2O3 Composite Films

2013 ◽  
Vol 209 ◽  
pp. 14-17
Author(s):  
Basavaraja Sannakki ◽  
Anita Gandhe ◽  
V.H. Doddamani
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Polymer Composite ◽  
Composite Films ◽  
Weight Percent ◽  
X Ray ◽  
Morphological Studies ◽  
Tan Δ ◽  
Al2o3 Films

Abstract. The PMMA with Fe2O3+ Al2O3 films at different weight percent have been used for measurement of dielectric properties such as dielectric constant, dielectric loss and a. c. conductivity as a function of frequency over the range 50 Hz – 5 MHz at room temperature. The dielectric constant and the dielectric loss (tan δ) of the polymer composite films decreases exponentially at lower frequencies over the range 100 Hz-1 kHz, where as above 1 kHz the values of dielectric constant remains same. But, it has been observed that the value of dielectric constant of PMMA composite films with Fe2O3+ Al2O3 increases as weight percent of Fe2O3+ Al2O3 increases. The a c conductivity of the polymer composite films remains constant over the frequency range 50 Hz to 300 K Hz and afterwards it increases exponentially. Further, PMMA with Fe2O3+ Al2O3 have been characterized using X-Ray diffractometer for the crystallinity. The morphological studies have been made using the FESEM.

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.

Effects of CuO and V2O5 Addition on Sintering Behavior and Microwave Dielectric Properties of (1-x)Ca2P2O7-xTiO2

2007 ◽  
Vol 336-338 ◽  
pp. 279-282
Author(s):  
In Sun Cho ◽  
Sang Gu Kang ◽  
Dong Wan Kim ◽  
Kug Sun Hong
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Microwave Dielectric

The effects of CuO and V2O5 addition on sintering behaviors and microwave dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics were investigated. With CuO and V2O5 addition, the sintering temperature of 0.7Ca2P2O7-0.3TiO2 can be effectively reduced from 1150 to 950oC. The dielectric constant of the low fired 0.7Ca2P2O7-0.3TiO2 ceramics was not significantly changed while the quality factor was affected by additives. The temperature coefficient of resonant frequency value was increased in negative value with the additive contents. V2O5 and CuO additives effectively improved the densification and dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics. The correlation between the phase constituents and the dielectric properties was investigated with additive contents.

Effect of the Annealing Temperature on Dielectric Properties of Bi1.5Zn1.0Nb1.5O7 Films Prepared by MOCVD

2008 ◽  
Vol 388 ◽  
pp. 175-178
Author(s):  
Hiroshi Funakubo ◽  
Shingo Okaura ◽  
Muneyasu Suzuki ◽  
Hiroshi Uchida ◽  
Seiichiro Koda
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Temperature Coefficient ◽  
Annealing Temperature ◽  
Relative Dielectric Constant ◽  
Fused Silica ◽  
The Other ◽  
Other Hand ◽  
Silica Substrates

Effect of annealing temperature on the dielectric properties of Bi1.5Zn1.0Nb1.5O7 films prepared on (111)Pt//(001)Al2O3 and (111)Pt/fused silica substrates by MOCVD was investigated. The tunability and the inverse of the dielectric loss [1/ (tan )] increased with increasing annealing temperature. Relative dielectric constant and temperature coefficient of the capacitance (TCC) increased with the crystallinity of the films. On the other hand, (1/tan ) was independent of the crystallinity of the films, but was dramatically increased by the annealing.

Effect of Sintering Temperature on CuO Doped Barium Zinc Tantalate (BZT) Dielectric Properties

2016 ◽  
Vol 840 ◽  
pp. 8-13
Author(s):  
Hidayani Jaafar ◽  
Zainal Arifin Ahmad ◽  
Mohd Fadzil Ain
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Relative Density ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Constant E ◽  
State Method ◽  
Tan Δ

The structure and dielectric properties of Barium Zinc Tantalate (BZT) doped by copper oxide (CuO) with a variety of values of mol% doping from 0, 0.1, 0.25, 1.0, 1.5 and 2.5 were prepared using a solid state method. The addition of CuO did not disturb the 1:2 ordering structure of the BZT ceramic. The grain size increased when the addition of doping increased. A small amount of doping elements increased the relative density. The dielectric constant (ɛr) value of the BZT significantly improved with the addition of the CuO for the specimens sintered at 1250°C and it could be explained by the increase of the relative density. The tan δ of the CuO doped with BZT ceramics is lower than pure BZT ceramics, and decreases as the CuO content increases. Meanwhile, for the percentage of bandwidth (%BW) it is shown that the best result is produced when it is doped with 0.25 mol% CuO and sintered at 1250°C. The best microwave dielectric properties obtained were ɛr=70.28, tan δ = 0.024, %BW = 7.83 which occurred for the 0.25 mol% doped CuO and when sintered at 1250°C/4 h.

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