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Low-Temperature Sintering and Dielectric Properties of BaSn(BO3)2 Ceramics (BaSn(BO3)2세라믹스의 저온소결 및 유전특성)

  • Nam, Myung-Hwa;Kim, Hyo-Tae;Hwang, June-Cheol;Nam, Joong-Hee;Yeo, Dong-Hoon;Kim, Jong-Hee;Nahm, Sahn
    • Journal of the Korean Ceramic Society
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    • 제43권2호
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    • pp.92-97
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    • 2006
  • Dolomite type $BaSn(BO_3)_2$ ceramics with rhombohedral crystal structure has been synthesized via solid state reaction route. Dielectric properties were measured for the samples sintered at $1050\~1200^{\circ}C$ for 2 h in air. Dielectric constant, loss tangent, and temperature coefficient were increased with sintering temperature due to the evolution of $BaSnO_3$, secondary, phase. Optimum dielectric properties were obtained at the $BaSn(BO_3)_2$ ceramics sintered at $1100^{\circ}C.\;CuO/Bi_2O_3$ was added to $BaSn(BO_3)_2$ ceramics to lower the sintering temperature for LTCC application, then Co and Fe-based coloring agents were added for colorizing the LTCC tape. Typical dielectric properties of $BaSn(BO_3)_2$ ceramics with $5 wt\%\;CuO/Bi_2O_3\;and\;3wt\%$ Co-coloring agent that sintered at $900^{\circ}C$ were $\varepsilon_r=9.89,\;tan{\delta}=0.92\times10^{-3},\;and\;TCC=112ppm/^{\circ}C$. Thus obtained LTCC tape was co-fired with Ag paste for compatibility test and revealed no sign of Ag reaction with the ceramics.

Synthesis and Characterization of GAP or GAP-co-BO Copolymer-based Energetic Thermoplastic Polyurethane (GAP 및 GAP-co-BO Copolymer계 에너지 함유 열가소성 폴리우레탄의 합성 및 특성)

  • Seol, Yang-Ho;Kweon, Jeong-Ohk;Kim, Yong-Jin;Jin, Yong-Hyun;Noh, Si-Tae
    • Applied Chemistry for Engineering
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    • 제30권6호
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    • pp.673-680
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    • 2019
  • GAP or GAP-co-BO based energetic thermoplastic elastomers (ETPEs) were synthesized by changing the hard segment content percent in the range of 30~45% by 5% difference. Thermal and mechanical properties of GAP-co-BO based ETPEs were compared to those of GAP based ETPEs. FT-IR results showed that the capability of forming hydrogen bond increases with increasing the hard segment content in GAP/GAP-co-BO based ETPE, and also the GAP-co-BO based ETPEs are stronger than GAP based ETPEs in the hydrogen bond formation. DSC and DMA results showed that the glass transition temperature (Tg) of GAP based ETPEs increased with the increment of the hard segment content, while the Tg of GAP-co-BO based ETPEs was maintained even the hard segment content increased. The storage modulus at room temperature of the GAP-co-BO based ETPEs was higher than that of the GAP based ETPEs. This was due to the strong phase separation behavior of the hard and soft segment of GAP-co-BO based ETPEs, which further resulted in the stronger breaking strength and lower tensile elongation at break point for GAP-co-BO based ETPE than the GAP based one.