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Development and Characterization of the Bonding and Integration Technologies Needed for Fabricating Silicon Carbide Based Injector ComponentsAdvanced ceramic bonding and integration technologies play a critical role in the fabrication and application of silicon carbide based components for a number of aerospace and ground based applications. One such application is a lean direct injector for a turbine engine to achieve low NOx emissions. Ceramic to ceramic diffusion bonding and ceramic to metal brazing technologies are being developed for this injector application. For the diffusion bonding technology, titanium interlayers (coatings and foils) were used to aid in the joining of silicon carbide (SiC) substrates. The influence of such variables as surface finish, interlayer thickness, and processing time were investigated. Electron microprobe analysis was used to identify the reaction formed phases. In the diffusion bonds, an intermediate phase, Ti5Si3Cx, formed that is thermally incompatible in its thermal expansion and caused thermal stresses and cracking during the processing cool-down. Thinner interlayers of pure titanium and/or longer processing times resulted in an optimized microstructure. Tensile tests on the joined materials resulted in strengths of 13-28 MPa depending on the SiC substrate material. Nondestructive evaluation using ultrasonic immersion showed well formed bonds. For the joining technology of brazing Kovar fuel tubes to silicon carbide, preliminary development of the joining approach has begun. Various technical issues and requirements for the injector application are addressed.
Document ID
20080033970
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Halbig,Michael C. (Army Research Lab. Cleveland, OH, United States)
Singh, Mrityunjay (Ohio Aerospace Inst. Cleveland, OH, United States)
Date Acquired
August 24, 2013
Publication Date
January 27, 2008
Subject Category
Metals And Metallic Materials
Funding Number(s)
CONTRACT_GRANT: WBS 561581.02.08.03.16.02
Distribution Limits
Public
Copyright
Public Use Permitted.

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