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β‐Si 3 N 4 Whiskers Embedded in Oxynitride Glasses: Interfacial Microstructure
Author(s) -
Sun Ellen Y.,
Alexander Kathleen B.,
Becher Paul F.,
Hwang ShyhLung
Publication year - 1996
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.1151-2916.1996.tb09025.x
Subject(s) - microstructure , materials science , transmission electron microscopy , surface energy , composite material , layer (electronics) , phase (matter) , crystallography , chemical engineering , nanotechnology , chemistry , engineering , organic chemistry
Interfacial microstructures in βP‐Si 3 N 4 ( w )‐Si‐Al‐Y‐O‐N‐glass systems were investigated by systematically varying the nitrogen content and the Al:Y ratio of the glass matrix. High‐resolution and analytical transmission electron microscopy (HREM and AEM) studies revealed that the interfacial microstructure is a function of the glass composition. No interfacial phases were formed in glasses with low Al:Y ratios and in glasses with high Al:Y ratios and low nitrogen content, whereas epitaxial growth of an interfacial layer (100–200 μm thick) on the βP‐Si 3 N 4 ( w ) occurred in a glass matrix with high Al:Y ratio and high nitrogen content. The interfacial layer was identified to be a β'‐SiAION phase. Interfaces containing the SiAION layer exhibited high debonding energy compared to Si 3 N 4 ( w )–glass interfaces. HREM studies indicated that the lattice‐mismatch strain in the SiAION layer was relieved by dislocation formation at the SiAION–Si 3 N 4 ( w ) interface. The difference in interfacial debonding energy was, hence, attributed to the local atomic structure and bonding between the glass‐β‐Si 3 N 4 and the glass–β'‐SiAION phases. This observation was clear evidence of the strong influence of glass chemistry on the interfacial debonding behavior by altering the interfacial microstructure.