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Fabrication of Highly Porous Silica Thermal Insulators Prepared by Gelation–Freezing Route
Author(s) -
Fukushima Manabu,
Yoshizawa Yuichi
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12723
Subject(s) - porosity , materials science , thermal conductivity , microstructure , gelatin , fabrication , composite material , thermal , porous medium , chemical engineering , thermal insulation , chemistry , organic chemistry , layer (electronics) , medicine , physics , pathology , meteorology , engineering , alternative medicine
Highly porous silica thermal insulators were produced by gelation of a gelatin solution with dispersed silica particles, followed by freeze‐drying and heating at 800°C. The relationship between the ice‐template morphology and the parameters involved in gelation freezing was investigated, in addition to the effect of the microstructure on the thermal conductivity of the silica insulators. The porosity and thermal conductivity of the insulators ranged from 88 to 98 vol% and from 0.168 to 0.054 W (m·K) −1 , respectively, both of which could be controlled by changing the silica content in the gel stage. Gelation–freezing route was proved to be a feasible and promising route for the production of very highly porous, machinable insulators.