The effects of oxide additions on the microstructure and R-curve behavior of in-situ reinforced silicon nitride

Journal Article · Wed Oct 15 04:00:00 EDT 1997 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(97)00240-6· OSTI ID:540899

Yang, J; Hirano, T; Sekino, T; Niihara, K ^[1]

---

1. 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

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPOSITE MATERIALS
CONCENTRATION RATIO
CORRELATIONS
FRACTURE MECHANICS
FRACTURE PROPERTIES
MAGNESIUM OXIDES
MICROSTRUCTURE
SILICON NITRIDES
ZIRCONIUM OXIDES