Ultra High Temperature Hafnium-based Materials for Propulsion Technologies

Rhenium is the current material of choice for Divert and Attitude Control Systems (DACS) components of due to its erosion resistance, high-temperature strength and compatibility with propellant products. However, disadvantages of Re include high cost and high density. Alternatives to Re such as composites, refractory metal alloys, and monolithic ceramics have been proposed, but all possess strength, oxidation and/or cost limitations. Materials based on the Hf-Ta-N system have potential of meeting service temperature, oxidation resistance, and thermal shock requirements for advanced 2760 degrees C (5000 degrees F) DACS. This potential was demonstrated during a Phase I effort where Plasma Processes established VPS parameters to fabricate dense specimens for characterization and oxidation evaluations. Oxidation studies identified a chemistry that demonstrated superior oxidation resistance. Though materials based on the Hf Ta N system appear promising, a methodical approach to material optimization and evaluation is warranted in order to sufficiently mature the technology for MDA system integration. The technical objective of a Phase II effort is to execute a methodical approach to further develop the Hf-Ta-N system, with the goal ultimately identify optimum chemistries capable of replacing Re components of DACS systems with 50% cost savings and 30% weight savings. Specific tasks will include processing optimization; characterization; oxidation studies; mechanical testing; and hot fire testing evaluations. This proposed material development effort will be directly beneficial to upgrades for SM-3, THAAD, Airborne Weapon Layer, Sea-based Terminal defense and various tactical missile systems.