Ultra High Temperature Hafnium-based Materials for Propulsion Technologies

Rhenium is the current material of choice for several critical hot gas path components of Divert and Attitude Control Systems (DACS) 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. Thus, the development of economical, reduced mass alternatives to Re for employment in oxidizing and rapid heating to temperatures above 2200 degrees C (4000 degrees F) remains a great interest. Cermets based on the Hf-Ta-N systems have been suggested, though few investigations of these materials have been conducted. Moreover, investigations that have been conducted were focused on uneconomical solid-state hot-pressing techniques. Plasma Processes proposes to employ vacuum plasma spray (VPS) technology in the exploration of cermets for DACS applications. The Phase I technical objective is to evaluate the microstructures and oxidation behavior of Hf-Ta-N cermets. Specifically, fabricated components will be characterized to identify microstructure, phase content and phase distribution. Micro-indent testing will be performed to pseudo-quantify the relative fracture toughness. Oxidation testing will be conducted to evaluate oxidation behavior. This proposed material development effort will be directly beneficial to upgrades for SM-3 and THAAD, as well as for new systems such Net-Centric Air Defense Element (NCADE).