The Evaluation of Thermoplastic Precursors for C/C-SiC Manufactured by Liquid Silicon Infiltration (LSI)

C/C-SiC composites, fabricated by the Liquid Silicon Infiltration process (LSI), typically use phenolic resin-based thermosets as carbon precursors. In contrast to this, two different thermoplastics (Polyetheretherketone PEEK and Polyetherimide PEI) were examined for their suitability as carbon precursors for C/C-SiC composites. The carbon fiber surfaces were pretreated between 400 °C and 800 °C in nitrogen atmosphere to modify the fiber/matrix bonding. The microstructures of the materials show an increasing SiC content with increasing fiber pretreatment temperature. The flexural strength of the resulting material was determined by 4-point-bending tests.