An electrophoretic deposition (EPD) technique was used to infiltrate a SiC-based matrix phase into the fine voids of a TyrannoTM-SA SiC preform with/without the application of ultrasound. The zeta potential and viscosity of the suspension were controlled to achieve a uniform and simultaneous deposition of all constituents. EPD was performed under a 10 V DC electric field for 30 minutes after adjusting the suspension pH to 3, in which the zeta potentials for all constituents were ≥ + 40mV. The composites fabricated by EPD combined with ultrasonication showed a much higher degree of infiltration due to the minimized surface sealing effect than those by EPD only. After hot pressing at 1750 oC for 2 hours, the density of the composites by the combined process was 99.5%, which is the highest SiCf/SiC density ever reported.

Keywords: SiCf/SiC composites, Electrophoretic deposition, Zeta potential, Slurry infiltration