Mesophase Pitch Precursors for Melt-Infiltrated CMCs

The hypersonics and rocket propulsion community have critical existing future needs for more affordable and producible ultrahigh temperature (UHT) ceramic matrix composite (CMC) materials possessing good oxidation and thermomechanical durability – especially for next-generation air-breathing in addition to solid or liquid propulsion component applications. ThisPhase 1 STTR proposal addresses the requirement to significantly improve the affordability, production throughput and environmental durability of UHT high temperature CMC RDE combustion chamber hardware via the use of high performance yet cost-effective MAX phase coated C-C/SiC CMCs produced via a combination of mesophase pitch impregnation and silicon melt infiltration processing. Exothermics and their Phase 1 STTR partners the University of Alabama Tuscaloosa, Materials Research & Design, and ACP Technologies will investigate the feasibility of employing ACPT’s pitches having various mesophase fractions as carbonaceous precursors for densification and reimpregnation of C-C composites that will then be melt-infiltrated. We will conduct process feasibility and optimization trials with the ACPT pitches by infusing into carbon fiber preforms, model the diffusion kinetics of proposed pitch stabilization treatments, and we will then build a series of demo and test articles to validate and characterize the C-C/SiC materials produced in Phase 1. EBC coating methods that will be developed and optimized in Phase 1. The program will conclude with a limited campaign of thermomechanical RDE simulation testing, and we will also make test articles available for plasma torch or small-scale ground testing at facilities such as Aerojet Rocketdyne’s Subscale Ramjet Facility rig in Orange VA.