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Migration of Silicate Liquid Out of Grain Boundaries in Ceramics

Published online by Cambridge University Press:  02 July 2020

N. Ravishankar
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota 421 Washington Ave SE, Minneapolis, MN55455-01432
C. Barry Carter
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota 421 Washington Ave SE, Minneapolis, MN55455-01432
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Extract

Liquid-Phase Sintering (LPS) is a conventional fabrication route for the densification of alumina and other ceramics. The polycrystalline ceramics processed by LPS contain siliceous phases along the grain boundaries. This wetting of the grain boundaries has a strong dependence on the crystallography of the boundary. The liquid preferentially wets certain orientations while some special boundaries are ‘dry’. The mechanism of dewetting of these boundaries is not well understood. Several approaches have been adopted to study the nature of the liquid-solid interaction at the grain boundaries. In commercial alumina, anorthite is the most commonly found intergranular phase.

Basal twist boundaries in alumina which contain a thin layer of anorthite glass have been investigated in the present study. Pulsed laser deposition has been used to deposit thin films of anorthite glass on optically flat basal sapphire. The substrate-film assembly is then bonded to an optically polished basal sapphire by sintering the assembly at 1650°C for 2h.

Type
Future of Microscopy: Ceramics, Composites, and Cement
Copyright
Copyright © Microscopy Society of America

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References

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