Effect of Fibre Heat-Treatment on Nicalon SiC Fibre Reinforced β-SiAlON Matrix Composites


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Nicalon SiC fibre tows have excellent properties for ceramic matrix reinforcement but residual oxygen within the fibres degrades fibre properties when these are incorporated into ceramic matrices at elevated temperatures. β-SiAlON ceramics also have excellent mechanical and physical properties, especially fracture toughness. However, sintering of β-SiAlON is generally carried out at 1650-1750°C, considerably higher than the temperatures above which fibre degradation occurs (>1200°C). In the present study, the refractoriness and strength of Nicalon fibres were improved by high pressure CO heat treatment, and densification temperatures of β-SiAlON were lowered by using different kinds of sintering additives. Heat-treatment of the fibres under 45 bar CO pressure at 1500-1650°C led to an increase in fibre strength and to the formation of a thin carbon layer on the surface of the fibres. These improvements in the Nicalon SiC fibres allowed them to be incorporated successfully into β-SiAlON matrices. The as-received and heat-treated fibres were infiltrated with β-SiAlON starting powder mixes and hot-pressed with low temperature sintering additives at 1600-1700°C for 30 min. Bending strength and fracture toughness measurements showed that samples containing heat-treated fibres provided a significant strength and fracture toughness increase compared with similar samples prepared using as-received fibres, and massive pull-out was observed because of the weak interface resulting from the surface carbon coating on the fibres.



Edited by:

Hasan Mandal




A. Demir and D. P. Thompson, "Effect of Fibre Heat-Treatment on Nicalon SiC Fibre Reinforced β-SiAlON Matrix Composites ", Materials Science Forum, Vol. 554, pp. 141-146, 2007

Online since:

August 2007




[1] K.K. Chawla: Ceramic Matrix Composites (second ed), Kluwer, Academic Press, Norvell (MA), Dordrecht, The Netherlands (2003).

[2] H. Ohnabe, S. Masaki, M. Onozuka, K. Miyahara and T. Sasa: Composites Part A: Appl Sci Manuf 30 (4) (1999), pp.489-496.

[3] H. Kaya: Comput Sci Technol 59 (6) (1999), pp.861-872.

[4] K. Ueno and T. Inoue: Ceram. Int. 23 (2) (1997), pp.165-170.

[5] S. Kitaoka, N. Kawashima, T. Suzuki, Y. Sugita, N. Shinohara and T. Higuchi: J. Am. Ceram. Soc. 84 (9) (2001), p.1945-(1951).

[6] N. Chandra and H. Ghonem: Composites Part A: Appl. Sci. Manuf. 32 (3-4) (2001), pp.575-584.

[7] T. Mah, N.L. Hetch, D.E. McCullen, J.R. Hoinigman, H.M. Kim, A.P. Katz and H.A. Lipsitt: J. Mater. Sci. 18 (1984), pp.119-201.

[8] Coustumer, P.L.: J. Eur. Ceram. Soc. (11) (1993), pp.139-49.

[9] A. Demir and D.P. Thompson: J. Mater. Sci. 36 (2001), pp.2931-2935.