Processing and properties of C _fibre /SiC _fillers /SiOC composites using solvent free liquid polysiloxane as matrix source

Carbon fibre reinforced SiOC composites (denoted as Cfibre/SiCfillers/SiOC) were prepared by slurry coating and polymer infiltration pyrolysis (PIP) process. Low viscosity liquid polysiloxane (PSO) and SiC powder were combined at a 1∶1 weight ratio to produce a blend (S-PSO), which was employed as matrix source. Heat treated carbon fibre fabric was adopted as the reinforcement. The lamination process was determined on the basis of cure and rheology investigations on S-PSO. The effects of PIP cycles and temperature of heat treatment of the carbon fibre on the mechanical properties of Cfibre/SiCfillers/SiOC were examined. The results indicate that composites using carbon fibres annealed at 1700°C as reinforcement reached a maximum flexural strength of 300 MPa after six PIP cycles. The resistance of the Cfibre/SiCfillers/SiOC composite to oxidation was also evaluated. Without any protective coatings, the composite retained 60% of its strength after oxidation at 800°C for 3 h in a static air environment.