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.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of the American Ceramic Society|
|State||Published - Jan 1993|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry