Fabrication of C/C-SiC composites via catalytic carbonization-in situ reacted and catalytic carbonization-reactive melt infiltration process

By aid of aluminium trichloride (AlCl3), an effective fabrication of the preform of carbon/carbon silicon carbide (C/C-SiC) composites via catalytic carbonization was developed, using coal tar as precursor at a low temperature. C/C-SiC composites were obtained by two different approaches, one combining catalytic carbonization and in-situ reacted (CC-ISR) method, the other combining catalytic carbonization and reactive melt infiltration (CC-RMI) method. Furthermore,the microstructure and mechanical properties of the resulted C/C-SiC composites were characterized. SiC nanowires distributed in the voids of interbundle and intrabundle of carbon fibers in as-prepared samples with CC-ISR process. The CC-ISR sample exhibits a pseudo-plastic fracture mode and its flexural strength is about (158±12) MPa. By contrast, the SiC morphology of composites fabricated in CC-RMI process contains cube and hexagonal grains. The fracture behavior of CC-RMI sample shows a brittle fracture mode and its flexural strength was about (150±10) MPa. Compared with the CC-RMI method,the C/C-SiC composites obtained by the CC-ISR method has many advantages such as simple technology,low cost and excellent mechanical properties.