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Nucleation of alpha alumina in boehmite gel

Published online by Cambridge University Press:  31 January 2011

Ladislav Pach ,
Rustum Roy  and
Sridhar Komarneni
Ladislav Pach
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
Rustum Roy
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
Sridhar Komarneni
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
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Abstract

Transformation of boehmitc-derived alumina gel to α–Al2O3 in unseeded gels is strongly influenced by the parent phase, θ-Al2O3. In seeded gels the perfect structure of the epitaxial substrate (α–Al2O3, 0.3 wt. %) influences the surrounding defect θ-phase resulting in (a) fewer imperfections due to lower transformation enthalpy to α–Al2O3, and (b) multiple nucleation sites of α–Al2O3 at the α–Al2O3 seed surface. The rate of transformation expressed for the same number of α–Al2O3 nuclei in unseeded and seeded gels indicates that it is faster in the unseeded gel than in the seeded gel.

Type
Articles
Information
Journal of Materials Research , Volume 5 , Issue 2 , February 1990 , pp. 278 - 285
Copyright
Copyright © Materials Research Society 1990

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References

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