Polymer Derived Ultra-High Temperature Ceramic Matrix Composites

Vehicles for extreme environments can experience exceptionally high heat fluxes resulting in high temperatures in oxidizing environments. Materials selection for such hot structures is limited to the most refractory systems, such as carbon/carbon composites coated with ultra-high temperature ceramics (UHTCs) or UHTC matrix composites (UHTCMCs). Recent Air Force Research Laboratory efforts have been focused on the synthesis, scale-up, and characterization of precursor polymers that can enable the production of UHTCMCs.

This presentation will introduce and discuss new preceramic polymers (termed Air Force Preceramics (AFPCs)) capable of producing UHTC materials, such as zirconium carbide (ZrC). The invention of these new AFPCs is significant as these polymers have properties (e.g., low viscosity, high ceramic yield, and compositional tunability) attractive for producing UHTCMCs. Specifically, AFPCs excel in infiltrating fiber tows allowing for densification of continuous UHTC matrix around individual carbon fibers on the micron-length scale, a desirable UHTCMC feature challenging to achieve with historical approaches (e.g., slurry methods). Within this presentation, AFPC-based production of UHTCMCs will be discussed, as well as the thermal/mechanical characterization and performance-testing of the finished composites. Knowledge from this work will enhance future capabilities for flight in extreme environments.