Preparation and properties of Ti₃SiC₂ preform reinforced SiC ceramic matrix composites

Ti₃SiC₂ preform reinforced SiC ceramic matrix composites (Ti₃SiC₂/SiC) were successfully fabricated through a novel near-net-shape process strategy combining molten salt synthesis with subsequent polymer infiltration and pyrolysis (PIP) for the first time. The effects of temperature and molten salt ratio on the phase composition, pore structure, and flexural strength of Ti₃SiC₂ preform were investigated in detail. The morphology and microstructure evolution of the composites during the PIP process were observed by SEM and TEM. The mechanical properties, electromagnetic interference shielding effectiveness (EMI SE) and thermal conductivity of Ti₃SiC₂/SiC were significantly improved compared to PDC-SiC, which benefits from the connected network skeleton of Ti₃SiC₂ preform. The flexural strength and fracture toughness of Ti₃SiC₂/SiC are 198.7 MPa and 4.5 MPa∙m^1/2. The EMI SE remains above 30 dB covering the entire X-band and its average value is 46.92 dB. The thermal conductivity is 6–7 W/(m·k) (25–1000 °C).