Processing of C-f/SiC composites by hot pressing using polymer binders followed by polymer impregnation and pyrolysis

摘要

Continuous carbon fiber (C-f) reinforced silicon carbide (SiC) matrix composite (C-f/SiC) was processed through hot pressing (HP) using polycarbosilane (PCS) in matrix and polysilazane in interphase regions as polymer binders. HP experiments were conducted at 4 MPa, 1200 degrees C and 1 h; followed by PCS polymer impregnation and pyrolysis (PIP) at 1200 degrees C under vacuum. The BN/SiC-Si3N4 interphase formed on the Cf cloth during BN dispersed polysilazane polymer coating and pyrolysis. The influence of PCS quantity during HP experiments on C-f/SiC composites was studied. Results suggest that sintering of SiC matrix in C-f/SiC composite improves by increasing PCS content during HP; however, high PCS content increases the liquidity of SiC-PCS mixture to flow out of the composite structure. The C-f/SiC composites with relative density ranging from 79 to 83% and flexural strength from 67 to 138 MPa was achieved.