Fabrication of SiC fiber reinforced SiC composite by chemical vapor infiltration for excellent mechanical properties

The process optimization for the forced-flow/thermal gradient chemical vapor infiltrated SiC based composites with an advanced SiC fiber(Tyranno SA) was carried out. The new SiC/SiC composites had a lower porosity and the uniform distribution of pores compared with conventional CVI. The uniform interphases between SiC fibers and matrix could be obtained by reversing the gas-flow direction mid-way through the coating process. The tensile strength was slightly increased with the thickness of carbon interphase in the range of 20–250 nm. It was found that the fabric layer orientation and multilayer SiC/C interphase were very effective to improve the mechanical properties.