| Project/Area Number |
10559013
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
広領域
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
OHSATO Hitoshi Material Science & Engineering, Nagoya Institute of Technology Professor, 工学部, 教授 (20024333)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIGAKI Susumu Daiken Chemical Co., Ltd., Director of R & D, 研究所, 所長
ADACHI Nobuyasu Material Science & Engineering, Nagoya Institute of Technology Research Professor, 工学部, 助手 (90262956)
OKUDA Takashi Material Science & Engineering, Nagoya Institute of Technology Professor, 工学部, 教授 (60233459)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥12,800,000 (Direct Cost: ¥12,800,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 1998: ¥6,200,000 (Direct Cost: ¥6,200,000)
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| Keywords | microwave dielectricity / dielectric resonator / portable phone / satellite broadcasting / mobile communication / tungstenbronze type like structure / crystal structure / material design / 共振器 |
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| Research Abstract |
We investigated emergence mechanisms in the properties of ceramic resonators, which support microwave communication for advanced information-oriented society, in the atom level based on the crystal structure. This research was performed for the purpose of the design and development of new ceramic resonators.
1 : It was succeeded in making sintering temperature decrease to 1350℃ for synthesis of modified Ba_<6-3x>R_<8+2x>Ti_<18>O_<54> (R=Sm, Nd) solid solutions with almost equivalent microwave dielectric properties to the solid solutions sintered at 1450℃. This was attained by that the starting mixing composition was sifted slightly to the TiO_2 side for making it the eutectic composition.
2 : The correlation with the soluble condition of Bi cation into Ba_<6-3x>R_<8+2x>Ti_<18>O_<54> (R=Sm, Nd) solid solutions and their micowave dielectric properties was made clear. The reason why Bi was chosen for the investigation was that Bi is known as a cation which made it promote sintering even at
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relative low temperature. Addition of Bi into Ba_<6-3x>R_<8+2x>Ti_<18>O_<54> (R=Sm, Nd) solid solutions was made it possible that the material was sintered at industrial applicable temperature of 1350℃ which was 100℃ lower than that needed for pure Ba_<6-3x>R_<8+2x>Ti_<18>O_<54> (R=Sm, Nd) solid solutions.
3 : Additive effects of BaWO_4 to the tungstenbronze type like Nd-system solid solutions were studied. Although an eutectic mixture was formed, no solid solutions were observed and its sintering temperature was as high as 1460℃. However, the improvement of the quality coefficient (Q fvalue : 2500 up) was seen by the addition of BaWO_4. On the other hand, the dielectric constant decrease and the temperature dependence of the frequency increased with addition of BaWO_4.
4 : The quality factor of the tungstenbronze type like Ba_<6-3x>R_<8+2x>Ti_<18>O_<54> (R=Sm, Nd, La) solid solutions was examined from the internal strain in the crystal structure. Accurate FWHM data obtained by using photon factory in the High Energy Accelerator Research Organization (KEK) made it clear that the quality factor observed in the solid solutions significantly depended on the internal strain of the crystal structure. It was cleared that Sm-system solid solutions, which exhibited the best microwave dielectric properties of all the systems, demonstrated the smallest internal strain of the crystal structure of the specimens examined.
5 : Further, effects of Eu additive on the microwave dielectric properties of Ba_<6-3x>R_<8+2x>Ti_<18>O_<54> (R=Sm, Nd) solid solutions were studied. It was cleared that Sm-Nd and Eu systems forms solid solutions. The quality factor Q f was improved to 11000GHz and the temperature coefficient (τ_f) at the resonant frequency was decreased by the addition of Eu. In the Sm-Eu system, a solid solution with τ_f of 0 and Q f of 9500GHz was obtained. Less
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