Discontinuous dissolution of iron aluminate spinel in the Al sub 2 O sub 3 -Fe sub 2 O sub 3 system

When sintered 85Al sub 2 O sub 3 -15Fe sub 2 O sub 3 (wt%) specimens consisting of corundum grains and spinel particles were annealed at temp. where only a corundum phase was stable, phase transformation of spinel into metastable FeAlO sub 3 and subsequently complete dissolution of the metastable ph...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1995-01, Vol.78 (8), p.2149-2152
Main Authors: Lee, Ho-Yong, Paek, Yeong-Kyeun, Lee, Byoung-Ki, Kang, Suk-Joong L
Format: Article
Language:English
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Summary:When sintered 85Al sub 2 O sub 3 -15Fe sub 2 O sub 3 (wt%) specimens consisting of corundum grains and spinel particles were annealed at temp. where only a corundum phase was stable, phase transformation of spinel into metastable FeAlO sub 3 and subsequently complete dissolution of the metastable phase occurred together with the migration of grain boundaries at the surface of the specimens. Since the grain boundary migration was induced by grain boundary diffusion of Fe sub 2 O sub 3 from the transforming and dissolving particles, the boundary migration by temp. decrease corresponded to a discontinuous dissolution of the spinel particles and a chemically induced grain boundary migration by temp. change. Inside the specimens, however, the transformation-dissolution and the grain boundary migration were suppressed because of unavailable accommodation of the vol expansion due to the transformation. 26 refs.
ISSN:0002-7820