Papers by Keyword: Ba2Ti9O20

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Authors: Mi Xiao, Cui Ran Jia, Chao Liu, Ming Yu, Qiang Song
Abstract: The effects of BaB2O4 glass on the synthesis of Ba2Ti9O20 were studied. The doping amounts of BaB2O4 varied from 0 to 10wt% and the compositions were sintered in the temperature range of 1200~1280C for 2h. The benefit of BaB2O4 addition to the densification of the ceramics is apparently due to the liquid phase which accelerates the migration of reactant species, which results in the decreasing of the sintering temperature. With the amount of BaB2O4 increased, the microstructure and properties of the ceramics were also changed: BaTi4O9 became the major phase instead of Ba2Ti9O20, bulk density decreased, and dielectric constant decreased accordingly, while dielectric loss kept small.
2257
Authors: Xin Ye Yang, Xiao Hui Wang, An Ji, Long Tu Li
Abstract: Both BaTi4O9 and Ba2Ti9O20 have the best microwave properties among many compounds in BaO-TiO2 system. The microwave performance of the ceramics in BaO-TiO2 system, which were prepared by conventional solid state method, was investigated in this paper. The study indicates that the (Ti,Zr)/Ba ratio has a great effect on the dielectric properties of the ceramic due to different BaTi4O9/Ba2Ti9O20 ratio. The pure BaTi4O9 ceramic exhibits the most outstanding microwave properties, with εr=35.55 and Q×f=43300GHz. On the contrary, the dielectric property of the pure Ba2Ti9O20 ceramic was not good enough, which should be doped with some additive additions. WO3 was incorporated into the system and the sintering temperature was adjusted to improve the microwave dielectric property. The Q×f was increased to 38000GHz by adding 1.35mol% WO3 due to the formation of a little BaWO4 phase. When sintered at a higher temperature (1380°C), the BaO-TiO2 system ceramic has εr =37.04 and Q×f =44874GHz.
1155
Authors: Sheng Guo Lu, Haydn Chen, C.L. Mak, K.H. Wong, H.W.L. Chan, C.L. Choy
Abstract: Ba2Ti9O20 (B2T9) and BaTi4O9 (BT4) ceramics have been fabricated using sol-gel technique. The sol-gel derived powder was produced from barium acetate and butyl titanate using acetic acid as solvent. The as-prepared powders were then calcined at different temperatures ranging from 600° to 1200°C. After that, the powder was pressed into pellets and further sintered at different temperatures ranging from 1250°C to 1380°C. XRD characterization and Raman spectroscopy showed that after calcining the sol-gel powder at 900°C for 2 h and sintering the pressed pellets at 1330°C for 4 h, triclinic B2T9 and orthorhombic BT4 ceramics could be obtained. The dielectric constant and Q-value are 35 and 1910 at 6.1 GHz.
47
Authors: Hui Xing Lin, Xiang Yu Zhao, Ai Min Yang, Hua Xin Li, Wei Chen, Lan Luo
Abstract: In this study, 2BaO-3B2O3 (BB) glass was used as a sintering aid to lower the sintering temperature of Ba2Ti9O20 ceramics. Microwave Characteristics of the BB-added Ba2Ti9O20 ceramics sintered at different temperatures were investigated. The crystalline phases of BB-Ba2Ti9O20 ceramics are Ba2Ti9O20, BaTi(BO3)2 and TiO2. Good microwave dielectric properties (εr = 26, Q*f = 28770GHz and τf = 14.6ppm/oC) were obtained by sintering the BB-added Ba2Ti9O20 ceramics at 1040oC for 2 h.
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