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27Al MAS-NMR spectra of alumina aerogels

Published online by Cambridge University Press:  03 March 2011

Yasuyuki Mizushima ,
Makoto Hori  and
Minoru Sasaki
Yasuyuki Mizushima
Affiliation:
Colloid Research Institute, 350-1 Ogura, Yahatahigashi-ku, Kitakyushu 805, Japan
Makoto Hori
Affiliation:
Colloid Research Institute, 350-1 Ogura, Yahatahigashi-ku, Kitakyushu 805, Japan
Minoru Sasaki
Affiliation:
Colloid Research Institute, 350-1 Ogura, Yahatahigashi-ku, Kitakyushu 805, Japan
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Abstract

The 27Al MAS-NMR spectra of alumina aerogels were determined. The spectra showed different profiles according to the supercritical methods used during drying. The alumina aerogel supercritically dried in a CO2 extractor (80 °C, 15.7 MPa) displayed a pentahedral-coordinated aluminum structure. On the other hand, the alumina aerogel supercritically dried in an autoclave (270 °C, 26.5 MPa) revealed no pentahedral-coordinated aluminum structure. The absence of pentahedral-coordinated aluminum was one factor for the lower temperature of transformation from the γ to the θ phase.

Type
Rapid Communications
Information
Journal of Materials Research , Volume 8 , Issue 9 , September 1993 , pp. 2109 - 2111
Copyright
Copyright © Materials Research Society 1993

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References

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