Reaction hot pressing of {alpha}{prime}- and {beta}{prime}0SiAlON ceramics
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering
Hot pressing kinetics of {alpha}-Si{sub 3}N{sub 4}, AlN, Al{sub 2}O{sub 3}, and Y{sub 2}O{sub 3} powder mixtures forming {alpha}{prime}- and {beta}{prime}-SiAlONs have been studied. Densification proceeds in two steps, first by a small shrinkage upon ternary eutectic oxide melting (SiO{sub 2}-Al{sub 2}O{sub 3}-Y{sub 2}O{sub 3}) at 1340 C, followed by a massive particle rearrangement and further shrinkage at higher temperature when nitride dissolution begins. With better wettability, AlN initially traps the oxide melt and delays densification. In addition, the preferential dissolution of AlN at 1450 C enriches the melt composition in Al, triggering transient precipitation of supersaturated {beta}{prime}-SiAlON. Full densification is readily achieved at 1550 C without complete {alpha}-Si{sub 3}N{sub 4} conversion.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 142248
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 1 Vol. 77; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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