High-Strength Carbide-Based Fibrous Monolith Materials for Solid Rocket Nozzles

Over the past 10 to 15 years, there has been a move towards the integration of ¡§advanced¡¨ materials with improved performance in hostile propulsion environments. Tantalum carbide is stable to very high temperatures (~3900„aC) under non-oxidizing conditions, but is relatively soft and erodes appreciably with aluminized propellants. In an effort to improve the strength and erosion resistance of TaC, ACR are working to refine the grain size thereby improving the strength. Second phase additions of other refractory carbides have been shown to significantly improve the hardness thereby increasing erosion resistance. During the Phase II effort the erosion resistance and strength will be optimized for boost nozzle applications for GBI. ACR will collaborate with Raytheon, Tucson, to provide design and thermal modeling guidance. Material systems will be screened at elevated temperatures using the Laser Hardened Materials Evaluation Laboratory (LHMEL) facility, and finally a large scale test will be carried out on the 2nd stage configuration at China Lake. It is expected that this improved TaC will show exceptional erosion resistance and unprecedented performance for boost applications. Future systems will incorporate energetic propellants and require boost nozzle throats with exceptional erosion resistance to resist abrasive aluminized propellants and hold dimensional stability.