Silicon/Silicon Carbide Composites Fabricated by Infiltration of a Silicon Melt into Charcoal

Dense Si/SiC composites were fabricated via a conventional reaction‐bonding process, using oak charcoal that exhibited a honeycomb structure. The silicon melt was infiltrated into the porous oak charcoal (density of ~0.6 g/cm3) while the sample was heated to 1700°C under vacuum (10‐3 torr (~0.133 Pa)), which resulted in in situ silicon‐fiber/SiC composites. The reaction product had an average density of 2.8 g/cm3 and showed three‐point flexural strengths of 330 MPa at room temperature and 280 MPa at 1300°C. Good oxidation resistance also was observed at temperatures up to 1300°C in flowing air. This process provided excellent shape‐making capability, because the charcoal that was used as a preform was readily machinable.