Microstructure and mechanical properties of C_f/SiC composites with dispersed C-SiC interphase prepared by chemical vapor infiltration

A simple and cost-effective method for preparing C_f/SiC composites with dispersed C-SiC interphase using fiber surface sizing agents is proposed and verified. The formation mechanism of the dispersed C-SiC interphase is investigated, and the effects of the dispersed C-SiC interphase on the interfacial bonding, strengthening, and toughening mechanisms of the composites are also evaluated. The results reveal that the dispersed C-SiC interphase is formed by the diffusion of SiC precursor molecules into the porous carbon coating derived from the decomposition of the sizing agent. The dispersed C-SiC interphase plays a similar role as the pyrolytic carbon interphase prepared by chemical vapor infiltration. The tensile strength and Weibull modulus of C_f/SiC composites with dispersed C-SiC interphase are 223 MPa and 5.19, respectively. This study has a positive application value for the manufacture of composites in terms of significantly reducing the preparation cost and cycle duration.