Characterization of Freeze-Dried Al2O3 and Fe2O3 |
| |
| Authors: | D. W. JOHNSON F. J. SCHNETTLER |
| |
| Affiliation: | Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey 07974 |
| |
| Abstract: | Oxide crystallite formation and growth from freeze-dried sulfates were studied for the representative materials Al2O3 and Fe2O3. Transmission and scanning electron micrographs showed the formation and growth of chainlike aggregates of crystallites. Aggregation occurred as part of the nucleation and growth of the oxide, and discrete oxide particles were never present. Orientation of the chain aggregates was related to the ice structure formed during freezing. X-ray line broadening data showed that crystallite size is a function of the 1/5 to 1/7 power of time for isothermal treatments. A qualitative analysis of material transport favored the surface diffusion mechanism. |
| |
| Keywords: | |
|
|
