Alpha alumina transformation in seeded boehmite gels

R. A. Shelleman, G. L. Messing, M. Kumagai

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Abstract

The kinetics and surface area changes during the γ to α-Al2O3 transformation sequence of an α-Al2O3 seeded boehmite sol-gel are compared to an unseeded boehmite sol gel. The seeded gels exhibited increased kinetics, however the activation energy for the γ to α-Al3O3 transformation was lowered only 17% indicating the α-Al2O3 transformation is growth controlled. Transmission electron microscopy showed that each α-Al2O3 seed acts as a multiple nucleation site for the θ to α-Al2O3 transformation. The higher surface area of the seeded boehmite results from the prevention of vermicular microstructure development. Thus, by seeding boehmite sol gels with α-Al2O3 the growth process during transformation to α-Al2O3 is controlled resulting in a fine, uniform microstructure which sinters at significantly lower temperatures.

Original languageEnglish (US)
Pages (from-to)277-285
Number of pages9
JournalJournal of Non-Crystalline Solids
Volume82
Issue number1-3
DOIs
Publication statusPublished - Jun 1 1986

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry

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