High-temperature behavior of Cf/SiOC composites in inert atmosphere

Three-dimensional carbon fiber reinforced silicon oxycarbide (3D Cf/SiOC) composites were fabricated through precursor infiltration and pyrolysis processing (PIP) using siloxane resin as precursor. These composites were further annealed at various temperatures to investigate their microstructure and mechanical property evolutions. It was found that the annealing temperature played a crucial role on the microstructure and mechanical properties of Cf/SiOC composites. When the annealing temperature increased from 1200 to 1400 °C, the mechanical properties of composites did not change too much, despite the matrixes underwent a redistribution of Si–O bonds and Si–C bonds. At temperature above 1500 °C, both the flexural strength and modulus decreased rapidly. This behavior was directly related to the weight loss and volume shrinkage of matrixes caused by carbothermal reductions occurred in matrixes.

► Cf/SiOC composites derived by PIP route are outstanding high-temperature structure materials.
► The mechanical properties of Cf/SiOC are almost constant at temperature below 1400 °C.
► The mechanical properties of Cf/SiOC decreased rapidly at temperature above 1500 °C.