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Silica Glass Segregation in 3 wt% LiF‐Doped Hot‐Pressed Y 2 Si 2 O 7
Author(s) -
MacLaren Ian,
Schierholz Roland,
Trusty Paul A.,
Ponton Clive B.
Publication year - 2007
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.1551-2916.2007.01863.x
Subject(s) - materials science , yttrium , microstructure , transmission electron microscopy , stoichiometry , hot pressing , doping , analytical chemistry (journal) , grain boundary , mineralogy , ceramic , silica glass , phase (matter) , composite material , metallurgy , nanotechnology , chemistry , oxide , optoelectronics , organic chemistry , chromatography
Hot‐pressed yttrium disilicate ceramics have been characterized using analytical transmission electron microscopy (TEM). The microstructure consists of large grains of the γ phase of stoichiometric γ‐Y 2 Si 2 O 7 containing rounded glassy Y‐doped SiO 2 inclusions; excess glassy SiO 2 ‐rich material is also found at the grain boundaries. Two main reasons are found for the inhomogeneity: a slight SiO 2 excess is inferred from the composition measurements, and the LiF flux used in hot pressing would also promote glass formation. Improved high‐temperature mechanical properties would only be possible if residual glass formation was minimized, strategies for doing so are discussed, and the importance of analytical TEM for studying such submicron scale inhomogeneity is underlined.