Non-Eroding Post-Boost Control Hot Gas Components Produced by Rapid Manufacturing Techniques

Innovative solutions are sought to reduce cost, lead-time and improve capability of hot gasmanagement components in the post boost control system (PBCS) of the U.S. Navys Trident IID-5 Fleet Ballistic Missile (FBM). Current PBCS components are based on refractory metals ofC103, Ta10W and TZM, with oxidation protective silicide coatings. At low oxygen pressure andhigh temperatures, gaseous species (SiO2(g) and SiO(g)) can form due to the vaporization of thesilicide coating. The vaporization and condensation of these gaseous species currently limitrange of the PBCS. Hafnium, a potential silicide alternative, forms an efficacious stablecondensed oxide (HfO2) when exposed to elevated temperature, oxidative environments similarto the hot gas paths of the PBCS. Other advantages of Hf include the following:- Continuous solid solution compatibility with many structural refractory metal materials;- Relatively high melting temperature of 4048F;- Very higher condensed oxide melting temperature of 5025F compared to 2900F forsilicide coating condensed oxide (SiO2);- Base metal and condensed oxide compatible with many oxidative solid rocketpropellants, such as HMX;- Application via multiple deposition techniques;- Economical, domestically sourced raw material.