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Volume 17, Issue 3, 2008
LETTER: TENSILE BEHAVIOUR OF SiC COATED CARBON/CARBON COMPOSITES AFTER EXPOSURE TO A CH4 COMBUSTION GAS
Chidong Liu*,1, Laifei Cheng1, Hui Mei1, Xingang Luan1, Hui Huang†,2
1 National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, 547 Mailbox, Xi’an Shaanxi 710072, China
2 State Key Laboratory of Powder Metallurgy, Central South University, Changsha Hunan 410083, China
* Author to whom correspondence should be addressed, e-mail: lcd_tscm@hotmail.com
Received 5 January 2008; accepted 4 July 2008
ABSTRACT
Tensile behaviour and microstructure of a SiC coated C/C composite were investigated after exposure to a CH4 combustion gas with flame temperatures of 1300 ºC and 1800 ºC. The tensile strength of the composite was respectively reduced to 61.9% and 77.7% of their original values. Superficial oxidation of the C/C substrate was responsible for strength reduction. Multi-tube-walled structure of the C/C substrate was observed after oxidation, which was caused by the difference in reactivity between the carbon fibre and the matrix. Silica spheres were observed to adhere to the C/C substrate beneath the coating, which was caused by active oxidation of SiC.
KEYWORDS: carbon/carbon composite; combustion gas environment; oxidation; residual property; microstructure
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