scholarly journals Microwave Sintering and Microwave Dielectric Properties of (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 Ceramics

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 438
Author(s):  
Shuwei Yang ◽  
Bingliang Liang ◽  
Changhong Liu ◽  
Jin Liu ◽  
Caisheng Fang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mobile Communications ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Dielectric Properties ◽  
Conventional Heating ◽  
Sintering Process ◽  
Microwave Dielectric ◽  
Sintering Time ◽  
Frequency Temperature

The (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 [(1–x)CLT-xNMT, x = 0.35~0.60] ceramics were prepared via microwave sintering. The effects of sintering temperature and composition on the phase formation, microstructure, and microwave dielectric properties were investigated. The results show that the microwave sintering process requires a lower sintering temperature and shorter sintering time of (1–x)CLT-xNMT ceramics than conventional heating methods. All of the (1–x)CLT-xNMT ceramics possess a single perovskite structure. With the increase of x, the dielectric constant (ε) shows a downward trend; the quality factor (Qf) drops first and then rises significantly; the resonance frequency temperature coefficient (τf) keeps decreasing. With excellent microwave dielectric properties (ε = 51.3, Qf = 13,852 GHz, τf = −1.9 × 10−6/°C), the 0.65CLT-0.35NMT ceramic can be applied to the field of mobile communications.

Effect of H3BO3 Additive and Forming Pressure on Microwave Dielectric Properties of 0.95MgTiO3-0.05CaTiO3

2014 ◽  
Vol 941-944 ◽  
pp. 521-524
Author(s):  
Jin Bao Huang ◽  
Yi Xiang Cai ◽  
Zhao Xian Xiong ◽  
Hao Xue
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Process ◽  
Microwave Dielectric ◽  
Method Effect ◽  
Best Value ◽  
Dielectric Ceramics ◽  
Quality Factor Q

0.95MgTiO3-0.05CaTiO3 (95MCT) microwave dielectric ceramics was prepared solid-state reaction method. Effect of H3BO3 additive and forming pressure on sintering process, microstructure and microwave dielectric properties of 95MCT were investigated. The result showed that the additive of H3BO3 can lower the sintering temperature of 95MCT, and improve the densification of 95MCT. MgTi2O5 was found as mesosphere, which can be effectively suppressed through the additive of H3BO3. Excellent microwave dielectric properties of ceramics was obtained when the H3BO3 additive was 0.50wt%. The best value of dielectric constant (εr), quality factor (Q×f) and temperature coefficient of resonant frequency (τf ) of 21.54, 67,286GHz and-4.1ppm/oC was obtained for the ceramics with sintering 1220oC for 2h.

Preparation and Microwave Dielectric Properties of Ca(Sm0.5Nb0.5)O3 Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1198-1202
Author(s):  
Jia Mao Li ◽  
Tai Qiu
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Cooling Rate ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Process ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Microwave Dielectric

Microstructures and microwave dielectric properties of Ca(Sm0.5Nb0.5)O3 ceramics, prepared by a conventional solid-state reaction method, were systematically investigated by varying calcining temperature, sintering temperature and cooling rate. The XRD result showed that a single Ca(Sm0.5Nb0.5)O3 phase could be synthesized at a calcining temperature of 1200 °C. Optimized combination of microwave dielectric properties of εr = 22.36, Q×f = 18030 GHz and τf = -31.2 ppm/°C was obtained for furnace-cooled Ca(Sm0.5Nb0.5)O3 ceramics sintered at 1550 °C for 4 h. However, some microcracks were found from the microstructures of the furnace-cooled specimens. Further, the Q×f value could be increased by controlling the cooling rate during the sintering process due to the disappearance of microcracks in the final material. With a cooling rate of 2 °C/min, Ca(Sm0.5Nb0.5)O3ceramics exhibited an enhanced Q×f value of 37130 GHz.

Effect of ZnO-V2O5 Co-Doping on Phase Stability and Microwave Dielectric Properties of ZnTiO3 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 297-300 ◽  
Author(s):  
Jing Yan ◽  
Zhen Xing Yue ◽  
Jin Wang ◽  
Fei Zhao ◽  
Zhi Lun Gui ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintering Process ◽  
Quality Factors ◽  
Zinc Titanate ◽  
Co Doping ◽  
Microwave Dielectric ◽  
Titanate Ceramics

Zinc titanate ceramics having excellent dielectric properties and low sintering temperature are promising materials for RF/microwave multilayer devices. In this paper, the ZnO-V2O5 addition was added to promote the sintering process in order to obtain low-temperature sintered ceramics with high quality factors. The sintering addition could also restrain ZnTiO3 phase from decomposition. Using this method, low-temperature sintered zinc titanate ceramics with excellent microwave dielectric properties of εr~ 25.3, Q×f~15200GHz, and τf ~ -16 ppm/oC were obtained at sintering temperature of 800oC. The low-fired mechanism, microstructure, phase formation and microwave dielectric properties of ceramics were investigated by XRD, SEM, EDS and network analysis techniques, respectively.

scholarly journals Effect of Microwave Sintering on the Properties of 0.95(Ca0.88Sr0.12)TiO3–0.05(Bi0.5Na0.5)TiO3 Ceramics

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 803 ◽  
Author(s):  
Lei Tian ◽  
Jing Nan ◽  
He Wang ◽  
Chunying Shen
Keyword(s):  
Resonance Frequency ◽  
Temperature Coefficient ◽  
Sintering Temperature ◽  
Dielectric Material ◽  
Microwave Sintering ◽  
Microwave Dielectric Properties ◽  
Important Research ◽  
Research Directions ◽  
Microwave Dielectric ◽  
Frequency Temperature

Perovskite ceramics are a common microwave dielectric material, but the development and application of this material has been limited by the high, positive resonance frequency temperature coefficient and sintering temperature. Therefore, adjusting the temperature coefficient of the resonance frequency and reducing the sintering temperature have become important research directions. In this work, 0.95(Ca0.88Sr0.12)TiO3–0.05(Bi0.5Na0.5)TiO3 ceramics (referred to as 0.95CST-0.05BNT) were prepared by standard solid-state reaction and microwave sintering. Microwave sintering greatly shortened the sintering period and holding time. Moreover, the 0.95CST–0.05BNT ceramics showed more uniform grain size distribution, and microwave sintering reduced energy consumption in the experiment. Therefore, the temperature coefficient of the resonance frequency of MWS ceramics was reduced by 119 × 10−6 /℃. All of the ceramics, which were sintered at 1300 °C for 40 minutes, showed optimal microwave dielectric properties: εr = 187.6, Q × f = 8958 GHz, and τf = +520 × 10−6 /°C.

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.

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