Melilite formation in a samarium-stabilized {alpha}-sialon ceramic during postsintering heat treatments
- Zhejiang Univ., Hangzhou (China). Dept. of Materials Science and Engineering
- Luleaa Univ. of Technology (Sweden). Dept. of Engineering Materials
- Stockholm Univ. (Sweden)
The formation of the melilite solid solution phase (M{prime}), Sm{sub 2}Si{sub 3{minus}x}Al{sub x}O{sub 3+x}N{sub 4{minus}x}, in an {alpha}-sialon sample of overall composition Sm{sub 0.6}Si{sub 9.28}Al{sub 2.69}O{sub 1.36}N{sub 14.76}, was studied as a function of time in the temperature interval 1,375--1,525 C. The {alpha}-sialon ceramic contained only minor amounts of the 21R sialon polytype and some residual grain-boundary glass before heat treatment. In situ studies by high-temperature X-ray diffraction were combined with postsintering heat treatment followed by quenching. The M{prime}-phase was found to be formed by two different mechanisms: either crystallization of the residual grain-boundary liquid or a direct decomposition of the {alpha}-sialon phase. The liquid crystallized during the first 10--15 min of heat treatment, yielding a rapid M{prime}-phase formation, and further formation of M{prime}-phase continued at a much slower rate, related to the decomposition of {alpha}-sialon.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 474168
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 80; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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