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.

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.

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.

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.

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.%.

Low-Temperature Firing and Microwave Dielectric Properties of Zn3Nb2O8 Ceramics with CuO-V2O5-Bi2O3

2010 ◽  
Vol 434-435 ◽  
pp. 224-227
Author(s):  
Xu Ping Lin ◽  
Jing Tao Ma ◽  
Bao Qing Zhang ◽  
Ji Zhou
Keyword(s):  
Dielectric Constant ◽  
Phase Composition ◽  
Dielectric Properties ◽  
Relative Density ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Co Doping ◽  
Microwave Dielectric ◽  
Quality Factor Q

The influence of CuO-V2O5-Bi2O3 addition on the sintering behavior, phase composition, microstructure and microwave dielectric properties of Zn3Nb2O8 ceramics were investigated. The co- doping of CuO, V2O5 and Bi2O3 can significantly lower the sintering temperature of Zn3Nb2O8 ceramics from 1150°C to 900°C. The Zn3Nb2O8-0.5wt% CuO-0.5wt% V2O5-2.0wt% Bi2O3 ceramic sintered at 900°C showed a relative density of 97.1%, a dielectric constant (εr) of 18.2, and a quality factor (Q×f) of 36781 GHz. The dielectric properties in this system exhibited a significant dependence on the relative density, content of additives and sintering temperature. The relative density and dielectric constant (εr) of Zn3Nb2O8 ceramics increased with increasing CuO-V2O5-Bi2O3 additions. And also the relative density and dielectric constant of Zn3Nb2O8 ceramics increased by the augment of the sintering temperature.

The Influence of AST Doping on the Dielectric Properties of MgTiO3-Based Ceramics Fabricated by Soild-State Sintering

2013 ◽  
Vol 634-638 ◽  
pp. 2378-2382
Author(s):  
Chun Yuan Luo ◽  
Jing Xiao Liu ◽  
Fei Shi ◽  
Ji Wei Wu ◽  
Chao Qian ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Liquid Phase ◽  
Dielectric Loss ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Process ◽  
Solid State Sintering ◽  
Doped Zno

AST-doped ZnO-MgTiO3-SrTiO3ceramics were prepared using a solid-state sintering process. The effects of AST (Al2O3-SiO2-TiO2) on the dielectric properties of MgTiO3-based ceramics were investigated. The results indicate that AST-doped MgTiO3-based ceramics could be obtained after 1205~1280°C sintering for 3 h. The XRD results indicate that the obtained MgTiO3-based ceramics contain high percentage of MgTi2O5 phase and the percentage increased with the increase of AST content. It was found that the occurred liquid-phase sintering by adding AST glass could effectively lower the sintering temperature and decrease the dielectric loss of MgTiO3-based ceramics. A minimum tanδ of 1.5×10-4 associated with εr=19.0 was achieved for 6.0 wt% AST-doped samples sintered at 1255°C.

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.

scholarly journals Sintering Behaviors, Microstructure, and Microwave Dielectric Properties of CaTiO3–LaAlO3 Ceramics Using CuO/B2O3 Additions

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4187 ◽  
Author(s):  
Min-Hang Weng ◽  
Chihng-Tsung Liauh ◽  
Shueei-Muh Lin ◽  
Hung-Hsiang Wang ◽  
Ru-Yuan Yang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Quality Factor Q

The effect of CuO/B2O3 additions on the sintering behaviors, microstructures, and microwave dielectric properties of 0.95LaAlO3–0.05CaTiO3 ceramics is investigated. It is found that the sintering temperatures are lowered efficiently from 1600 °C to 1350 °C, as 1 wt % CuO, 1 wt % B2O3, and 0.5 wt % CuO +0.5 wt % B2O3 are used as the sintering aids due to the appearance of the liquid phase sintering. The microwave dielectric properties of 0.95LaAlO3–0.05CaTiO3 ceramics with the sintering aid additions are strongly related to the densification and the microstructure of the sintered ceramics. At the sintering temperature of 1300 °C, the 0.95LaAlO3–0.05CaTiO3 ceramic with 0.5 wt % CuO + 0.5 wt % B2O3 addition shows the best dielectric properties, including a dielectric constant (εr) of 21, approximate quality factor (Q × f) of 22,500 GHz, and a temperature coefficient of the resonant frequency (τf) of −3 ppm/°C.

Effects of additives on the microstructure and dielectric properties of Ba2Ti9O20 microwave ceramic

2003 ◽  
Vol 18 (5) ◽  
pp. 1179-1187 ◽  
Author(s):  
Sea-Fue Wang ◽  
Yung-Fu Hsu ◽  
Tzuu-Hsing Ueng ◽  
Chung-Chuang Chiang ◽  
Jinn P. Chu ◽  
...  
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Decomposition Temperature ◽  
Nonstoichiometric Compound ◽  
Microwave Ceramic ◽  
Phase Pure ◽  
Excess Amount ◽  
Evolution Phase

Preparation of dense and phase-pure Ba2Ti9O20 is generally difficult to achieve using a solid-state reaction, due to the presence of several thermodynamically stable compounds in the vicinity of the desired composition. This work investigated the effects of various additives (TiO2, MnO, and ZrO2) on the densification, microstructural evolution, phase stability, and dielectric properties of Ba2Ti9O20. Ceramics with theoretical density of ≥95% were achieved in all cases after sintering at 1300 °C. A pure Ba2Ti9O20 phase was obtained by treating the material with TiO2 additions (≤5.6 wt.%) and sintering at temperatures ranging between 1200 and 1350 °C. Ba2Ti9O20 is a nonstoichiometric compound that can accommodate an excess amount of TiO2. As the temperature was increased, pure Ba2Ti9O20 partially decomposed and formed a mixture of BaTi4O9 and Ba2Ti9O20. The ceramic with excess TiO2 sintered at 1390 °C possessed a higher permittivity and a lower quality factor due to the larger grain size and lower density. For ceramic with the addition of ZrO2 (≤6 wt.%), pure Ba2Ti9O20 phase was obtained after sintering between 1200 and 1390 °C, and the quality factor was improved. The decomposition temperature of the Ba2Ti9O20 phase was greater than 1390 °C. For sintering temperatures ≥1350 °C, the extent of Ba2Ti9O20 phase decreased with MnO additions. As the MnO content reached 0.5 wt.%, only BaTi4O9 and TiO2 phases existed, suggesting a decrease in the decomposition temperature of Ba2Ti9O20 with the addition of MnO. The microwave properties of the ceramics degraded significantly at the sintering temperature of 1390 °C.

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