A Novel Reactive Joining Compound for High Temperature Applications

37 A Novel Reactive Joining Compound for High Temperature Applications--Sienna Technologies, Inc., 19501 144th Avenue NE, Suite F-500, Woodinville, WA 98072-8424; (425) 485-7272 Dr. Cetin Toy, Principal Investigator Dr. Ender Savrun, Business Official DOE Grant No. DE-FG03-97ER82474 Amount: $74,993 The joining of various materials to one another is a critical technological capability in many areas of interest to the Department of Energy including electrical power generation and automotive systems. The absence of reliable techniques to join ceramic materials to themselves and to metals precludes the development of more advanced energy conversion systems such as gas turbines and thermoelectric devices. While metal brazing has been used to successfully join ceramics to each other and to metals, commercially available brazing alloys have limited capabilities at high temperatures. In this project, a novel solid-state bonding approach is proposed to make silicon carbide-silicon carbide (SiC-SiC) joints. Several compositions will be investigated to develop a reliable reactive joining compound. The new material could be used to repair cracks and join the SiC parts in the field. The Phase I study will demonstrate that solid-state joining of the SiC to SiC is feasible using the newly developed compound. Room and high temperature mechanical properties of the joints will be measured. Microstructure and microchemistry of the interface will be characterized. Phase I will also identify potential compositions for a pressureless joining process to be investigated in Phase II. The effect of process parameters on joint mechanical strength, microstructure, and microchemistry will be investigated in Phase II to develop a field-applicable, pressureless joining technique. Commercial Applications and Other Benefits as described by the awardee: The commercial application of such a joining compound would be SiC-based ceramic heat exchangers, pump components, and repair of SiC heating elements. The reactive compound would be in the form of a paste so that it could easily be printed, squeezed, or painted onto the surfaces which require repairing or joining.