Intermediate-Stage Densification in Vacuum Hot-Pressing of Alumina

The densification kinetics preceding the final‐stage densification of Al2O3 hot‐pressed in vacuum between 1150° and 1350°C and between 2000 and 6000 psi were analyzed. The analysis suggests a diffusion‐controlled creep mechanism but is not necessarily consistent with a Nabarro‐Herring vacancy model....

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1970-11, Vol.53 (11), p.629-633
Main Authors: ROSSI, R. C., BUCH, J. D., FULRATH, R. M.
Format: Article
Language:English
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Summary:The densification kinetics preceding the final‐stage densification of Al2O3 hot‐pressed in vacuum between 1150° and 1350°C and between 2000 and 6000 psi were analyzed. The analysis suggests a diffusion‐controlled creep mechanism but is not necessarily consistent with a Nabarro‐Herring vacancy model. The measured activation energy, 116 kcal/mol, agrees with the activation energy for the final stage of densification and for the self‐diffusion of Al ions in Al2O3. It is proposed that the pore structure (i.e. open or closed) defines the stage of densification and, further, that pore structure has a profound effect on the apparent diffusion coefficients.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1970.tb15988.x