Phase transformation and processing of polycrystalline gadolinium selenide, GdSe sub / 1.49

Polymorphic phase transformation in GdSe sub / 1.49/ from cubic to orthorhombic symmetry from 800- 1000 degrees C causes a 1% vol expansion which generates microcracks. Sintered polycrystalline cubic GdSe sub / 1.49/ preforms with < or = 97% densities were vacuum annealed at 900 degrees for 300 h...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1984-01, Vol.67 (10), p.664-667
Main Author: Wei, George C T
Format: Article
Language:English
Online Access:Get full text
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Summary:Polymorphic phase transformation in GdSe sub / 1.49/ from cubic to orthorhombic symmetry from 800- 1000 degrees C causes a 1% vol expansion which generates microcracks. Sintered polycrystalline cubic GdSe sub / 1.49/ preforms with < or = 97% densities were vacuum annealed at 900 degrees for 300 h to convert to the orthorhombic lattice, encapsulated in Ni containers, and then isostatically hot-pressed. Hot-pressing < or = 1000 degrees resulted in 96%-dense orthorhombic polycrystals containing large pores, whereas hot-pressing > 1200 degrees produced fully dense cubic polycrystals with a duplex microstructure. The electrical resistivity is discussed.
ISSN:0002-7820