Abnormal grain growth in alumina: synergistic effects of yttria and silica

MacLaren, I. , Cannon, R. M., Gülgün, M. A., Voytovych, R., Popescu-Porigon, N., Scheu, C., Täffner, U. and Rühle, M. (2003) Abnormal grain growth in alumina: synergistic effects of yttria and silica. Journal of the American Ceramic Society, 86(4), pp. 650-659. (doi:10.1111/j.1151-2916.2003.tb03354.x)

Full text not currently available from Enlighten.

Abstract

Abnormal grain growth without strong anisotropy or faceting of the grains has been observed in high-purity yttria-doped alumina specimens, often starting at the surface and spreading right through the bulk at higher sintering temperatures. This appears to occur because of an interaction between Si contamination from sintering and the yttria doping; no such effect is seen for undoped samples. Similar microstructures were observed after deliberate Y/Si codoping. Analytical STEM showed that some grain boundaries bordering on large grains contained more Si than Y. HRTEM and diffuse dark-field imaging revealed thin (0.5–0.9 nm) disordered layers at some boundaries bordering large grains. It appears that Si impurities are accumulating at some boundaries and together with the Y inducing a grain boundary structural transformation that accounts for the dramatically increased mobility of these boundaries.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:MacLaren, Dr Ian
Authors: MacLaren, I., Cannon, R. M., Gülgün, M. A., Voytovych, R., Popescu-Porigon, N., Scheu, C., Täffner, U., and Rühle, M.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Journal of the American Ceramic Society
Publisher:Wiley
ISSN:0002-7820
ISSN (Online):1551-2916

University Staff: Request a correction | Enlighten Editors: Update this record