The mechanical properties and thermal conductivity of carbon/carbon composites with the fiber/matrix interface modified by silicon carbide nanofibers

• SiCNFs induce the ordered deposition of PyC during CVI.
• A granular interface layer composed of CNFs and high texture PyC around them appears.
• The mechanical properties of C/C composite are adjusted.
• The thermal conductivity of C/C composite is enhanced.

For modification, silicon carbide nanofibers (SiCNFs) are uniformly dispersed on the fiber surface of the unidirectional carbon preform. The modified unidirectional carbon preform was then densified to obtain SiCNF–C/C composites by chemical vapor deposition (CVD). The microstructure of SiCNF–C/C composites was investigated. The mechanical properties and thermal conductivity of the modified composites were analyzed as well. Results show that PyC preferentially deposits on the surface of SiCNFs with high degree of order. The interface between carbon fibers and matrix has high texture, resulting in a good bonding between them. The mechanical properties of C/C composites are adjusted. After modification, the fracture mode is changed and the flexural strength is enhanced, especially in vertical direction. The thermal conductivity of modified composites is also enhanced in both vertical and parallel directions.

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