Reaction densification of {alpha}{prime}-SiAlON. I: Wetting behavior and acid-base reactions

Journal Article · Tue Feb 28 23:00:00 EST 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08212.x· OSTI ID:79763

Menon, M; Chen, I W ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

Phase development during reaction hot pressing of {alpha}-Si{sub 3}N{sub 4}, AlN, Al{sub 2}O{sub 3}, and M{sub 2}O{sub z} powder mixtures (M = Li, Mg, Ca, Y, Nd, Sm, Gd, Dy, Er, and Yb) forming {alpha}{prime}-SiAlON has been studied. The wetting behavior of the ternary eutectic melt of M{sub 2}O{sub z}-Al{sub 2}O{sub 3}-SiO{sub 2} was found to control the reaction sequence during hot pressing. Li, Ca, Mg, Nd. Sm, and Gd were found to preferentially wet and react with Si{sub 3}N{sub 4} first, whereas Dy, Er, and Yb preferentially wetted and reacted with AlN first. The intermediate phases are Si rich in the former and Al rich in the latter case. Pearson`s principle of acid-base theory, which predicts decreasing basicity of oxides of Li, Ca, Mg, Nd, Gd. Sm, Dy, Er, and Yb and decreasing acidity of oxides of Si and Al, is used to understand these reactions.

• Sponsoring Organization: USDOE
• OSTI ID: 79763
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM NITRIDES
ALUMINIUM OXIDES
CALCIUM OXIDES
CHEMICAL REACTIONS
DOPED MATERIALS
DYSPROSIUM OXIDES
ERBIUM OXIDES
GADOLINIUM OXIDES
HOT PRESSING
LATTICE PARAMETERS
LITHIUM OXIDES
MAGNESIUM OXIDES
NEODYMIUM OXIDES
POWDERS
SAMARIUM OXIDES
SILICON NITRIDES
SOLID SOLUTIONS
WETTABILITY
YTTERBIUM OXIDES
YTTRIUM OXIDES