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Migration of Aluminum Atoms in the Transformation of γ–to θ–Alumina

Published online by Cambridge University Press:  01 February 2011

Shu-Hui Cai  and
Karl Sohlberg
Shu-Hui Cai
Affiliation:
Department of Physics, Xiamen University, Xiamen 361005, P.R.C. Department of Chemistry, Drexel University, Philadelphia, PA 19104, U.S.A.
Karl Sohlberg
Affiliation:
Department of Chemistry, Drexel University, Philadelphia, PA 19104, U.S.A.
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Abstract

γ– and θ–alumina are two metastable phases of aluminum oxide observed along the thermal dehydration sequence of boehmite before conversion to the final product α–alumina. The transformation from γ– to θ–alumina was studied by using Al16O24 cells. Motion of some Al atoms from their γalumina positions to new positions and no O motions result in an approximate structure that, upon relaxation by first-principles calculations, becomes the known θ–alumina structure. Total-energy calculations along the paths of the atomic motions have been used to map out transformation pathways. The model accurately predicts experimentally observed domain boundaries in θ–alumina and the γ– to θ–alumina conversion rate.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 731: Symposium W – Modeling and Numerical Simulation of Materials Behavior and Evolution , 2002 , W3.6
Copyright
Copyright © Materials Research Society 2002

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