Transformation, Microstructure Development, and Densification in α-Fe2O3-Seeded Boehmite-Derived Alumina |
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| Authors: | James L McArdle Gary L Messing |
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| Affiliation: | Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 |
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| Abstract: | Addition of α-Fe2O3 seed particles to alkoxide-derived boehmite sols resulted in a 10-fold increase in isothermal rate constants for the transformation of γ- to α-Al2O3. Changes in porosity and surface area with sintering temperature showed no effect of seeding on coarsening of the transition alumina gels, but the 200-fold decrease in surface area associated with transformation to α-Al2O3 occurred ～ 100°C lower in seeded gels compared with unseeded materials. As a result of high nucleation frequency and reduced microstructure coarsening, fully transformed seeded alumina retained specific surface areas >22 m2/g and exhibited narrow pore size distributions, permitting development of fully dense, submicrometer α-Al2O3 at ～ 1200°C. |
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