Fabrication of SiCf/SiC composites by alternating current electrophoretic deposition (AC–EPD) and hot pressing

Alternating current electrophoretic deposition (AC–EPD) was used to infiltrate a SiC-based matrix phase containing Al2O3–Sc2O3 sintering aids into the fine voids of a two-dimensionally woven Tyranno™-SA3 SiC fabric preform for the fabrication of a dense SiC fiber-reinforced SiC composite (SiCf/SiC). The zeta potential of the aqueous suspension was set to ≥−55 mV to achieve uniform and simultaneous deposition of all constituent particles. EPD was performed at 20 V AC for 30 min under the application of ultrasonic pulses for the initial 20 min to minimize the surface sealing effect. A high SiCf/SiC density of 96.5% along with a flexural strength of 413.9 ± 18.5 MPa was achieved after hot pressing at 1750 °C for 1 h due to the high degree of matrix phase infiltration. These results showed that an eco-friend AC–EPD process can be applied to the fabrication of high density SiCf/SiC.