Fabrication of ZrC, HfC, TaC-based Fibrous Monolithic Ceramics for Rocket Propulsion Systems

The goal of this program is to develop a low cost, flexible manufacturing method for the production of high temperature ceramic composites for rocket propulsion systems. The matrix materials selected for this program will be ZrC, HfC, and TaC. These-materials have good oxidation/corrosion and ablation resistance at elevated temperatures, but typically do not possess the thermal shock resistance and toughness necessary to survive in many propulsion applications. To enhance the thermal shock resistance and toughness of these materials, without compromising their ablation and corrosion response, this program will use a novel approach to fabricating ZrC-, HfC-, and TaC-based composites using the proven 'Fibrous Monolith' processing technology. The fibrous monolith process creates an interpenetrating microstructure of elongated polycrystalline cells of the matrix material, in this case high temperature carbides, separated by thin cell boundaries of a low shear strength refractory material, such as graphite or BN. This interpenetrating microstructure imparts toughness and thermal shock resistance to the material. The technology allows for the fabrication of complex composite architectures to be readily fabricated from inexpensive powders and polymers. Phase I success will allow future iterations to optimize these composites for DOD/NASA needs during Phases II and III.