High Temperature Composite Coatings for C-Substrates for Rocket Motor Applications

Achieving the NAVY goal to dramatically increase the current state-of-the-art strategic solid rocket motor and gas generator components is critically dependent on the development of high performance materials systems. In order to meet these goals, non-eroding throat materials design solutions and also an affordable processing technology are critically needed. Presently, the desired capability of non-eroding performance under anticipated operating conditions are met by refractory carbides and borides on the porous C- substrates. In a phase I program, Surmet proposes to leverage its experience in refractory nano-carbonitrides materials to develop Ta-Hf-C, Ta-Zr-C and Ta-Hf-Zr-C coatings for C-substrates. The carbides in these systems are noted to have some of the highest melting points and also lowered vapor pressure at very high temperatures. Surmet experience in densification of these materials as singular/multi-layer coatings would be beneficial in developing dense coatings that are mechanically stable on C-substrates. Further improvements such as in-situ formation of refractory borides would potentially lead to more damage tolerant composite coatings. In the option phase of the program, Surmet plans to demonstrate viability of these materials for components and in the phase II, Surmet will team up with end users to further the technology and develop components for field evaluation.