Effect of chemical vapor infiltration on the flexural properties of C/C-SiC composites prepared by the precursor infiltration pyrolysis method

Carbon/carbon-silicon carbide (C/C-SiC) composites were prepared by impregnation, hot-pressing with curing, carbonization at 800 ^oC and high-temperature heat treatment (800-1600 ^oC) using a 2D laminated carbon cloth as the reinforcing filler, and furfurone resin mixed with silicon, carbon from furfurone resin and SiC powders as the matrix. The effects of the addition of the three powders as well as subsequent chemical vapor infiltration (CVI) by methane on the density, microstructure and bend strength of the composites were investigated by scanning electron microscopy, density measurements, X-ray diffraction and mechanical testing. Both the SiC powders formed by the reaction at 1600 ^oC between the added Si and C particles and the added SiC powder, play a role in the reinforcement of the materials. In three-point bending, the composites had a pseudoplastic fracture mode and showed interlaminar cracking. After 10 h CVI with methane, pyrolytic carbon was formed at the interface between some of the carbon fibers and the resin carbon matrix, which produced maximum increases in the density and flexural strength of the composites of 4.98% and 38.86%, respectively.