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Microstructural Evolution in Near‐Eutectic Yttrium Silicate Compositions Fabricated from a Bulk Melt and as an Intergranular Phase in Silicon Nitride
Author(s) -
Lee William E.,
Drummond Charles H.,
Hilmas Gregory E.,
Kumar Suresh
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.tb04260.x
Subject(s) - intergranular corrosion , materials science , eutectic system , yttrium , phase (matter) , silicate , silicon , silicon nitride , metallurgy , mineralogy , microstructure , chemical engineering , chemistry , organic chemistry , engineering , oxide
Near‐eutectic composition Y 2 O 3 ─SiO 2 melts were formed as bulk samples or as an intergranular phase in Si 3 N 4 . Upon cooling to room temperature the bulk material partially crystallized to γ‐Y 2 ‐Si 2 O 7 whereas the intergranular phase was glass. On heat‐treating at 1500°C the bulk material transformed to γ‐Y 2 Si 2 O 7 whereas the intergranular glass crystallized first to γ‐Y 2 Si 2 O 7 and then to β‐Y 2 Si 2 O 7 . Possible reasons for the different behavior are discussed.