Description: The outstanding properties of silicon carbide (SiC) include excellent specific strength, extreme chemical resistance, tremendous hardness, and retention of its high strength at very high temperatures. The brittleness typically associated with a ceramic can be mitigated by forming composites with either carbon or SiC fibers. However, the processes for forming SiC matrix composites limit the size and complexity of the resulting shapes. It is therefore necessary to develop techniques for efficiently joining SiC matrix composite parts. Many such methods have been proposed over the past 25 years, but none is satisfactory, and it remains an active area of research. The joints formed so far either require extremely high temperatures to manufacture or result in unsatisfactory mechanical properties. TDA is herein proposing a route that will result in a pure SiC bond, and will achieve it without requiring any external heat source. As such the joint will be robust, and have the same temperature capabilities and mechanical properties as the matrix. The technology will have met the criteria for exiting technical readiness level (TRL) 3, and some of the criteria for TRL 4, by the end of the Phase I period.

Benefits: Monolithic SiC parts are widely used in crucibles, furnace linings, and combustors in high temperature chemical processing. SiC/SiC composites have demonstrated long life in industrial gas turbines. SiC matrix composites are also extremely promising for use in nuclear energy reactor cores due to their radiation stability, thermal stability and excellent thermal fatigue resistance. They have also been studied for use in nuclear fusion plants as plasma-facing components, structural members, and even heat exchangers.

C/SiC and SiC/SiC matrix composites have been proposed for a wide variety of aerospace applications. Its outstanding high temperature materials properties and chemical resistance has lead to its consideration for use in leading edges and other thermal protection systems, combustion chambers and nozzles, nozzle flaps, and afterburner flame holders. Their high dimensional stability across cryogenic, ambient and elevated temperatures has lead to their consideration as mounts for spaceborne optical platforms.