Innovative Joining of Ultra-High Temperature Ceramics (UHTC) for TPS Applications

Ultra High Temperature Ceramics (UHTC’s) such as zirconium and hafnium diboride based composites are of particular interest for hypersonic leading edges due to their extreme refractoriness. Successful integration into hypersonic structures will require high strength / high temperature joints to bond ceramic-ceramic or ceramic-metal that can sustain the mechanical and thermal loadings at speeds of Mach 5+. New materials and UHTC joining technologies are necessary to fully integrate and exploit their high temperature properties in hypersonic vehicles. Bonding materials that are similar to the joining pair materials are desirable to provide the best thermo-mechanical match to bulk materials. Spark Plasma Sintering (SPS) has become a novel approach to rapidly consolidate ceramics; however, it could be adapted to rapidly join UHTC pairs. A team comprised of Advanced Ceramics Manufacturing (ACM) and the University of Arizona propose the use of Off Stoichiometric UHTCs and a modified SPS sintering technique to produce a rapidly bonded UHTC-UHTC geometry with properties similar to that of the bulk joining pair. BENEFIT: The technology proposed offers a new material brazing system that will produce joints for UHTCs with properties similar to that of the bulk joining pairs. This will allow better, more complex geometries for thermal protections systems (TPS). The materials can be rapidly bonded using adapted Spark Plasma Sintering (SPS) technology which will allow joints to be formed quickly. This joining technology will have commercial applications for turbine engines and commercial space launch vehicles.