{beta}-Si{sub 3}N{sub 4} whiskers embedded in oxynitride glasses: Interfacial microstructure
- Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
Interfacial microstructures in {beta}-Si{sub 3}N{sub 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 {micro}m thick) on the {beta}-Si{sub 3}N{sub 4}(w) occurred in a glass matrix with high Al:Y ratio and high nitrogen content. The interfacial layer was identified to be a {beta}{prime}-SiAlON phase. Interfaces containing the SiAlON layer exhibited high debonding energy compared to Si{sub 3}N{sub 4}(w)-glass interfaces. HREM studies indicated that the lattice-mismatch strain in the SiAlON layer was relieved by dislocation formation at the SiAlON-Si{sub 3}N{sub 4}(w) interface. The difference in interfacial debonding energy was, hence, attributed to the local atomic structure and bonding between the glass-{beta}-Si{sub 3}N{sub 4} and the glass-{beta}{prime}-SiAlON phases. This observation was clear evidence of the strong influence of glass chemistry on the interfacial debonding behavior by altering the interfacial microstructure.
- OSTI ID:
- 413314
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 10 Vol. 79; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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