Synthesis and Refinement of β-SiAlON by Nitriding and Post-Sintering of Si Mixture

Abstract:

A cost-effective route to synthesize β-SiAlONs from Si mixture by reaction bonding followed by post-sintering was investigated. Three different z values, 0.45, 0.92 and 1.87 in Si6-zAlzOzN8-z, without excess liquid phase were selected to elucidate the mechanism of both SiAlON formation and densification. For the RBSN(reaction-bonded silicon nitride) specimens, nitridation rate of more than 90% was achieved by multistep heating up to 1400oC in flowing 5%H2-95%N2 and residual Si was not detected by XRD analysis. Increase in density was observed with z values for the post-sintered specimens and this tendency was well explained by the presence of higher amount of transient liquid phase with larger z values. Measured z values of the synthesized -SiAlONs were nearly similar to calculated values using starting compositions. The slight deviation in the two z values was successfully explained by the reasonable assessment of nitriding and post-sintering process.

• Periodical: Key Engineering Materials (Volume 403)
• Pages: 95-96
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.403.95
• Online since: December 2008
• Authors: Young Jo Park, Eun Ah Noh, Joong Ho Ahn, Hai Doo Kim
• Keywords: Nitriding, Post Sintering, RBSN, Silicon, ß-SiAlON

References

[1] N. L. Parr, R. Sands, P. L. Pratt, E. R. W. May, C. R. Shakespeare and D. S. Thompson: Powder Met. Vol. 8 (1961), p.152.

[2] S. Kurama, M. Herrmann and H. Mandal: J. Europ. Ceram. Soc. Vol. 22 (2002), p.109.

[3] M. A. Einarsrud and M. Mitomo: J. Am. Ceram. Soc. Vol. 76(6) (1993), p.1624.

[4] T. Ekstrom, P. O. Kall, M. Nygren and P. O. Olsson: J. Mater. Sci. Vol. 24 (1989), p.1853.