Lowering the sintering temperature and enhancing densification by epitaxy in structurally diphasic Al2O3 and Al2O3MgO xerogels

Yoshiko Suwa, Rustum Roy, Sridhar Komarneni

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

The densification and sintering behavior of diphasic xerogels derived from boehmite and Al2O3MgO compositions seeded with α-Al2O3, spinel (MgAl2O4), α-Fe2O3, Cr2O3, kaolinite and Ludox was studied by measuring densities and by microstructural characterization of sintered materials. Isostructural seeding with the final equilibrium phase, i.e. α-Al2O3 in boehmite and α-Al2O3 and spinel in Al2O3MgO gels, resulted in enhanced densification as well as sintering at lower temperatures. Solid state epitaxy appears to be the mechanism by which isostructural seeding affects the densification and sintering behavior. Microstructural characterization revealed uniform grain growth with little or no porosity in the gels with isostructural seeds, while non-uniform grain growth and porosity were seen in unseeded gels as well as in gel with nonisostructural seeds. Isostructural seeding may become a generalizable process for enhancing densification and sintering in sol-gel ceramic processing.

Original languageEnglish (US)
Pages (from-to)151-159
Number of pages9
JournalMaterials Science and Engineering
Volume83
Issue number1
DOIs
StatePublished - Jan 1 1986

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Xerogels
Densification
Epitaxial growth
Sintering
Gels
Grain growth
Seed
Porosity
Temperature
Kaolinite
Phase equilibria
Sol-gels
Processing
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

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abstract = "The densification and sintering behavior of diphasic xerogels derived from boehmite and Al2O3MgO compositions seeded with α-Al2O3, spinel (MgAl2O4), α-Fe2O3, Cr2O3, kaolinite and Ludox was studied by measuring densities and by microstructural characterization of sintered materials. Isostructural seeding with the final equilibrium phase, i.e. α-Al2O3 in boehmite and α-Al2O3 and spinel in Al2O3MgO gels, resulted in enhanced densification as well as sintering at lower temperatures. Solid state epitaxy appears to be the mechanism by which isostructural seeding affects the densification and sintering behavior. Microstructural characterization revealed uniform grain growth with little or no porosity in the gels with isostructural seeds, while non-uniform grain growth and porosity were seen in unseeded gels as well as in gel with nonisostructural seeds. Isostructural seeding may become a generalizable process for enhancing densification and sintering in sol-gel ceramic processing.",
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Lowering the sintering temperature and enhancing densification by epitaxy in structurally diphasic Al2O3 and Al2O3MgO xerogels. / Suwa, Yoshiko; Roy, Rustum; Komarneni, Sridhar.

In: Materials Science and Engineering, Vol. 83, No. 1, 01.01.1986, p. 151-159.

Research output: Contribution to journalArticle

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