Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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Mechanical Strength and Thermal Conductivity of Pure/Opacified Silica Aerogels

순수/불투명화 실리카 에어로겔의 기계적 강도 및 열전도도

  • 현상훈 (연세대학교 세라믹공학과) ;
  • 이찬호 (연세대학교 세라믹공학과) ;
  • 김동준 (연세대학교 세라믹공학과) ;
  • 성대진 (한국표준과학연구원, 온도그룹)
  • Published : 1997.09.01
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Abstract

The properties of microstructure, hydrophobicity/hydrophilicity, mechanical strength, and thermal conduction of pure/opacified silica aerogels synthesized by the sol-gel supercritical drying technique were investigated. The hydrophobic surface of opacified silica aerogels doped with carbon (0.13 g/cm3 density, 94% porosity, 580 m2/g specific surface area) transformed to hydrophilic surface after heat-treated above 30$0^{\circ}C$. The values of compressive modulus (1.85 MPa) and strength (0.5 MPa) of opacfied silica aerogels were about 20 times higher than those of pure silica aerogels. The mechanical properties of pure silica aerogels heat-treated at $700^{\circ}C$ were also considerably improved without changing their porosity and density. Particularly, compressive modulus and compressive strength of pure silica aerogels GPSed under 100$0^{\circ}C$ and 80 bar were improved 140 and 37 times, respectively. Thermal conductivities of pure/opacified silica aerogels measured at room temperature and 227$^{\circ}C$ were about 0.013 and 0.019 W/m.K, respectively, and were to be found very low value of 0.004 W/m.K below 10 torr pressure at room temperature.

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