Nucleation of Alpha Alumina in Boehmite Gel

Ladislav Pach; Rustum Roy; Sridhar Komarneni

doi:10.1557/JMR.1990.0278

Nucleation of Alpha Alumina in Boehmite Gel

Ladislav Pach, Rustum Roy, Sridhar Komarneni

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92 Scopus citations

Abstract

Transformation of boehmite-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 0-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.

Original language	English (US)
Pages (from-to)	278-285
Number of pages	8
Journal	Journal of Materials Research
Volume	5
Issue number	2
DOIs	https://doi.org/10.1557/JMR.1990.0278
State	Published - Feb 1990

All Science Journal Classification (ASJC) codes

General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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title = "Nucleation of Alpha Alumina in Boehmite Gel",

abstract = "Transformation of boehmite-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 0-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.",

author = "Ladislav Pach and Rustum Roy and Sridhar Komarneni",

note = "Funding Information: This research was supported by the Air Force Office of Scientific Research under Contract F49620-85-C- 0069. The senior author gratefully acknowledges helpful discussions with Dr. W. A. Yarbrough and Dr. G. L. Messing.",

year = "1990",

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doi = "10.1557/JMR.1990.0278",

language = "English (US)",

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pages = "278--285",

journal = "Journal of Materials Research",

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publisher = "Materials Research Society",

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TY - JOUR

T1 - Nucleation of Alpha Alumina in Boehmite Gel

AU - Pach, Ladislav

AU - Roy, Rustum

AU - Komarneni, Sridhar

N1 - Funding Information: This research was supported by the Air Force Office of Scientific Research under Contract F49620-85-C- 0069. The senior author gratefully acknowledges helpful discussions with Dr. W. A. Yarbrough and Dr. G. L. Messing.

PY - 1990/2

Y1 - 1990/2

N2 - Transformation of boehmite-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 0-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.

AB - Transformation of boehmite-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 0-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.

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Nucleation of Alpha Alumina in Boehmite Gel

Abstract

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