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| Carbon/carbon silicon carbide composites (C/C-SiC) were rapidly fabricated by a two-steps processing. Firstly a short-cut carbon fiber felt (SC) and a 2D carbon fiber felt (2D) were densified to C/C composites by a thermal gradient chemical vapor infiltration (CVI) method with vaporized kerosene as a precursor in 2h, 3h, 4h and 5h, respectively. Then the two types of the C/C composites were infiltrated and reacted with melting silicon at ~1600oC to obtain C/C-SiC composites. The influences of the fiber architectures and the CVI time on the microstructure and mechanical property of the C/C-SiC composites were investigated. The results show that, with increase of the CVI time, the densities of the two types of C/C-SiC composites decrease in the range of 2.28g/cm3 to 2.00g/cm3; their porosities increase ranging from 1.3% to 7.5%; the contents of the β-SiC and the unreacted Si phases in the composites decline. The flexural strength of the 2D_C/C-SiC composite is much higher than that of the SC_C/C-SiC composite when prepared in the same condition. The 2D_C/C-SiC (CVI time=4h) composite has the highest flexural strength, which is ~130MPa. The mechanism of how the carbon fiber architecture influences the Si infiltration and the mechanical property of the C/C-SiC composite was illuminated. |
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| Keywords:Carbon fiber;SiC;Chemical vapor infiltration;Microstructure;Mechanical property |
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