Preparation and formation mechanism of C/C-SiC composites using polymer-Si slurry reactive melt infiltration

This study proposes a polymer-metal slurry reactive melt infiltration (RMI) method to overcome the limitations of conventional RMI in modifying irregular geometric carbon-carbon (C/C) preforms. Herein, polycarbosilane (PCS), polysiloxane, phenol-formaldehyde, and epoxy resin, which were introduced to prepare slurries with Si powder, and subsequently used to modify cylindrical C/C preforms into C/C-SiC composites. Results show that the PCS-Si slurry has the best RMI capability, by which, a cylindrical C/C preform (1.35 g-cm(-3)) was modified successfully to into a dense C/C-SiC composite (1.92 g.cm(-3)). PCS plays a vital role in fixing the coating to prevent it from falling off the surface of the C/C preform in PCS-Si slurry RMI. Both of the degree of densification and flexural strength of the C/C-SiC composites increase with an increase in the thickness of the PCS-Si slurry coating. The overreaction of the PCS-Si slurry RMI was effectively suppressed because the content of Si powder is reasonably controlled in the PCS-Si slurry coating. Moreover, nozzle-shaped C/C composites were successfully modified into a C/C-SiC composite for the first time using PCS-Si slurry RMI.