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Microstructure of 96% Alumina Ceramics: III, Crystallization of High‐Calcia Boundary Glasses
Author(s) -
PowellDoǧan Cynthia A.,
Heuer Arthur H.
Publication year - 1990
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1990.tb04276.x
Subject(s) - devitrification , microstructure , crystallization , materials science , grain boundary , ceramic , mineralogy , annealing (glass) , composite material , metallurgy , chemical engineering , geology , engineering
The crystallization characteristics of a group of 96% Al 2 O 3 ceramics containing a high‐CaO boundary glass were examined using a combination of electron microscopy techniques. As many as six crystalline phases formed at the boundaries during anneals between 1000° and 1350°C. Devitrification was rapid, and little glass remained following a 1‐h anneal. Despite the extensive changes in grain‐boundary microstructure, heat treatment had little effect on the room‐temperature mechanical properties of these Al 2 O 3 materials; however, high‐CaO bodies fractured intergranularly, whereas high‐MgO bodies fractured transgranularly.