• Title/Summary/Keyword: Glass composites

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Preparation of Carbon Composite with High Oxidation Resistance by MoSi2 Dispersion

  • Goto, S.;Kodera, M.;Toda, S.;Fujimori, H.;Ioku, K.
    • The Korean Journal of Ceramics
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    • v.5 no.2
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    • pp.115-118
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    • 1999
  • Carbon composites with $MoSi_2$ dispersion were prepared by hot-pressing at $1700^{\circ}C$ under 30 MPa for 1 h using polysilazance as binding material. The composites consisted of C, $Mo_{4.8}Si_3C_{0.6}$ and SiC. Bulk density and porosity of the carbon composites with 10 vol% $MoSi_2$ was 1.8g.$\textrm{cm}^{-3}$ and 34%, respectively. This composite was oxidized about 0.05mm from the surface of the carbon composite after oxidation test at $1500^{\circ}C$ for 10h in air. Formation of the $SiO_2$ glass layer was observed by SEM. When this composite suffered damage in the coating layer, it had hardly farther oxidation because of its self-repairing property. The composite prepared in this study indicated good oxidation resistance.

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Thermal, Mechanical, and Electrical Properties for EMNC_60 and EMNC_65 (EMNC_60과 EMNC_65에 대한 열적, 기계적, 전기적 특성 연구)

  • Park, Jae-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.11
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    • pp.895-901
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    • 2012
  • In order to application for high voltage heavy electric equipments, epoxy/microsilica 60 wt%/nano layered silicate composites (EMNC_60) and epoxy/microsilica 65 wt%/nano layered silicate composites (EMNC_65) respectively was synthesized by our electric field dispersion method and the result was obtained completely dispersion state. Thermal properties such as glass transition temperature (Tg) and thermal expansion coefficient, and DMA characteristics were studied, and mechanical properties such as tensile and flexural tests were performed. AC electrical insulation strength was also tested. The study on thermal property, EMNC_65 was better than EMNC_60 and mechanical, electrical properties much improved EMNC_60 compared with EMNC_65.

High Temperature Gas Leak Behavior of Glass-Ceramic Fiber Composite Seals for SOFC Applications (SOFC용 유리-세라믹섬유 복합기밀재의 고온 기체누설 거동)

  • Lee, Jae-Chun;Kwon, Hyuk-Chon;Kwon, Young-Pil;Park, Sung;Jang, Jin-Sik;Lee, Jongho;Kim, Joosun;Lee, Hae-Won
    • Journal of the Korean Ceramic Society
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    • v.42 no.12 s.283
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    • pp.842-845
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    • 2005
  • Glass composites containing ceramic fiber have been developed for Solid Oxide Fuel Cell (SOFC) seals. Effect of glass type, loading pressure and thermal cycle the leak rates of composite seals was investigated. Seal performance of two commercial glasses was compared with that of $SiO_2BaO-B_2O_3$ glass synthesized in this work. The leak rate for seals made of pyrex(R) increases from $\~0.0005\;to\;\~0.004sccm/cm$ as the gas pressure increases from 10 to 50 kPa. The soda lime silicate glass seal shows the leak rate two times higher than the one made of pyrex(R) or $SiO_2BaO-B_2O_3$ glass. The viscosity of glass at the seal test temperature is presumed to affect the leak rate of the glass seal. As the applied loading pressure increases from 0.4 to 0.8 MPa at $750^{\circ}C$, the leak rate decreases from 0.038 to 0.024 sccm/cm for composite seals. It has been found that during 50 thermal cycles between $450^{\circ}C\;to\;700^{\circ}C$ leak rates remained almost constant, ranging from 0.025 to 0.03sccm/cm. The results showed an excellent thermal cycle stability as well as sealability of the glass matrix ceramic fiber composite seals.