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Synthesis of Porous Ceramics Through Directional Solidification and Freeze-Drying

Published online by Cambridge University Press:  01 February 2011

Predrag Kisa ,
Patrick Fisher ,
Al Olszewski ,
Ian Nettleship  and
Nicholas G. Eror
Predrag Kisa
Affiliation:
Materials Science and Engineering Department, 848 Benedum Hall, University of Pittsburgh, Pittsburgh PA 15213, USA
Patrick Fisher
Affiliation:
Materials Science and Engineering Department, 848 Benedum Hall, University of Pittsburgh, Pittsburgh PA 15213, USA
Al Olszewski
Affiliation:
Materials Science and Engineering Department, 848 Benedum Hall, University of Pittsburgh, Pittsburgh PA 15213, USA
Ian Nettleship
Affiliation:
Materials Science and Engineering Department, 848 Benedum Hall, University of Pittsburgh, Pittsburgh PA 15213, USA
Nicholas G. Eror
Affiliation:
Materials Science and Engineering Department, 848 Benedum Hall, University of Pittsburgh, Pittsburgh PA 15213, USA
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Abstract

This study investigated the microstructural characteristics of directionally solidified freeze-dried silica sols. Porous structures were formed by depositing silica sol on silicon (100) single crystals. The deposited sols were unidirectionaly solidified by placing the silicon substrate on a copper block immersed in liquid nitrogen and then subsequently freeze-dried. Freeze drying removal of ice crystals created three-dimensional pore channels ranging from 3 to10 micrometers in diameter aggregated in grain like colonies 50–100 micrometers in diameter. Pore size, spacing, colony size and microstructure were determined using optical microscopy (OM) and scanning electron microscopy (SEM) while the structure of the amorphous SiO2 was characterized by X-ray diffraction (XRD). The microstructure results are compared and contrasted with silica aerogel obtained through conventional processing using supercritical CO2.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 788: Symposium L – Continuous Nanophase and Nanostructured Materials , 2003 , L8.7
Copyright
Copyright © Materials Research Society 2004

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References

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