High Temperature, High-Strength Refractory CMC Pintles for Controllable Solid Propulsion Systems

Pintles, in controllable solid propulsion systems face a challenging operating environment that includes very high temperatures and large thermal gradients. Increasing the performance of these systems makes that environment even more challenging, as pintles in a solid motor are attached to or near sensitive electrical components that cannot be exposed to high temperatures. Ultramet proposes its carbon fiber-reinforced zirconium carbide matrix (Cf/ZrC) CMC as an improved pintle material. Ultramet’s rapid melt infiltration process by which the Cf/ZrC CMC is fabricated is well-established and capable of producing highly dense, high toughness, low thermal conductivity refractory CMCs that are well-suited for extreme environment applications in solid propulsion systems. Ultramet also proposes to explore the concept of using chemical vapor deposition (CVD) to apply a rhenium tip to the CMC pintle shaft as a sealing surface. Rhenium maintains its structural and chemical integrity at extremely high temperatures and has proven performance as a pintle coating in tactical solid rocket motor applications. The materials to be used in this project are geared toward fulfilling the need for a more robust structural insulator for various components in solid propulsion system upgrades, including pintle shafts, pintle shaft couplings, and pintle insulators. The Ultramet Cf/ZrC CMC will provide the necessary high temperature thermal insulation for critical actuator components as well as high mechanical, chemical, and dimensional stability in the solid rocket combustion environment. Approved for Public Release | 22-MDA-11215 (27 Jul 22)