Layered silicon nitride ceramics with improved flaw tolerance

Kyeong Sik Cho, H. J. Choi, J. G. Lee, Y. W. Kim

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In situ-toughening of silicon nitride can result in dramatic improvements in toughness and R-curve properties. However, the improved toughness is offset by a notable reduction in strength. This problem can be overcome through the fabrication of a layered ceramics. By placing a thin layer of high-strength material on the surface of a high-toughness body, the toughness and flaw tolerance of the whole body can be maintained without sacrificing strength. In this study, α-Si3N4 and β-Si3N4 seeded α-Si3N4 were used for the surface layer and inner layer, respectively. The inner layer was formed by isostatic pressing and subsequent annealing, and the surface layer was coated on it by controlled dipping. The surface layer consisted of relatively fine β-grains with duplex microstructure, while the inner layer consisted of relatively coarse β-grains with duplex microstructure. The layered material showed stronger R-curve behavior and better flaw tolerance than monolithic materials. The processing and mechanical properties of these materials were discussed.

Original languageEnglish
Pages (from-to)245-250
Number of pages6
JournalKey Engineering Materials
Volume159-160
Publication statusPublished - 1999 Dec 1

Fingerprint

Silicon nitride
Toughness
Defects
Microstructure
Toughening
Annealing
Fabrication
Mechanical properties
silicon nitride
Processing

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Cho, K. S., Choi, H. J., Lee, J. G., & Kim, Y. W. (1999). Layered silicon nitride ceramics with improved flaw tolerance. Key Engineering Materials, 159-160, 245-250.
Cho, Kyeong Sik ; Choi, H. J. ; Lee, J. G. ; Kim, Y. W. / Layered silicon nitride ceramics with improved flaw tolerance. In: Key Engineering Materials. 1999 ; Vol. 159-160. pp. 245-250.
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Cho, KS, Choi, HJ, Lee, JG & Kim, YW 1999, 'Layered silicon nitride ceramics with improved flaw tolerance', Key Engineering Materials, vol. 159-160, pp. 245-250.

Layered silicon nitride ceramics with improved flaw tolerance. / Cho, Kyeong Sik; Choi, H. J.; Lee, J. G.; Kim, Y. W.

In: Key Engineering Materials, Vol. 159-160, 01.12.1999, p. 245-250.

Research output: Contribution to journalArticle

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