The effects of oxide additions on the microstructure and R-curve behavior of in-situ reinforced silicon nitride
- Osaka Univ., Ibaraki, Osaka (Japan). Inst. of Scientific and Industrial Research
The present paper describes results of an experimental study in which the R-curves for gas-pressure sintered silicon nitrides having different amounts of MgAl{sub 2}O{sub 4} and ZrO{sub 2} (3%Y{sub 2}O{sub 3}) were assessed by way of the indentation-strength technique. MgAl{sub 2}O{sub 4} (spinel) was selected as a sintering aid since it has more beneficial effect on the sintering of Si{sub 3}N{sub 4} ceramics than an Al{sub 2}O{sub 3} and MgO mixture and since MgO can prevent pores being formed by reaction between Si{sub 3}N{sub 4} and Al{sub 2}O{sub 3}. ZrO{sub 2} was added to the mixed powder because it has potential as a toughening and strengthening agent in Si{sub 3}N{sub 4}-based ceramic materials. The total amounts of the additives are between 5% and 15%. An object of this study is to compare the microstructure and flaw tolerance of four kinds of Si{sub 3}N{sub 4} ceramics. Particular emphasis is placed on understanding the relationship among the composition, microstructure and R-curve behavior.
- OSTI ID:
- 540899
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 8 Vol. 37; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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