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Volume 15, Issue 3, 2006
LETTER: EFFECT OF POLYCARBOSILANE CONTENT ON MICROSTRUCTURES AND MECHANICAL PROPERTIES OF SHORT-CARBON-FIBRE-REINFORCED SiC COMPOSITES
Xiulan He1,*, Yuguang Dai2, Yinggui Guo1, Yu Zhou3, Dechang Jia3
1 Department of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China
2 Research Institute, Northeast Light Alloy Company LTD., Harbin 150060, China
3 Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
* Author to whom correspondence should be addressed, Tel.: +86-451-86392500, E-mail Address: hexiulan1973@yahoo.com.cn
Received 4/06; accepted 6/06
ABSTRACT
Short-carbon-fibre-reinforced SiC composites were prepared by precursor pyrolysis-hot pressing with Polycarbosilane (PCS) as precursor polymer and MgO-Al2O3-Y2O3 as sintering additives. The effects of PCS content on microstructures and mechanical properties of the composites were investigated. The results showed that, the composites could be densified at a relatively low temperature of 1800oC via the liquid-phase-sintering mechanism and the highest mechanical property was obtained for the composites with 20 wt. % PCS content. During sintering, Y2O3, Al2O3 reacted with the pyrolysis products from PCS and formed amorphous interphase, which was benefit of densification of the composites and avoidance of degeneration of the carbon fibres. The nano PCS-derived SiC almost lied on the surface of the particle of starting powder ß-SiC, which could play a role of filling up the void and improve the relative density of the composites.
KEYWORDS: Short-carbon-fibre-reinforced SiC composite. Polycarbosilane Microstructure. Mechanical properties
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