Boron Nitride-Based Fiber Coatings for 3D Fiber-Reinforced Ceramic Composites Navy SBIR FY2005.1 Sol No.: Navy SBIR FY2005.1 Topic No.: N05-010 Topic Title: Boron Nitride-Based Fiber Coatings for 3D Fiber-Reinforced Ceramic Composites Proposal No.: N051-010-0429 Firm: Hyper-Therm High-Temperature Composites, Inc. 18411 Gothard Street Unit B Huntington Beach, California 92648 Contact: Robert Shinavski Phone: (714) 375-4085 Web Site: www.htcomposites.com Abstract: Hot structures fabricated from ceramic composites materials are being developed for future aerospace vehicles and propulsion systems to reduce weight and increase component lifetimes. Fabric-based ceramic composite components are vulnerable to delamination when the ceramic composite has a low through-thickness strength and is subjected to high through-thickness thermal gradients and/or normal loads. The objective of the proposed effort is to demonstrate the feasibility of producing an affordable fiber-reinforced ceramic matrix composite material having a low dielectric constant and significantly improved interlaminar properties. Angle interlock fiber preforms will be utilized to improve the through-thickness strength characteristics of the ceramic composite. The functionality of low dielectric constant boron nitride-based fiber coatings will be demonstrated in these composites. A high strength, low dielectric silicon nitride matrix will also be demonstrated and compared to a Si-N-C matrix. Benefits: Fiber-reinforced ceramic matrix composites are an enabling class of materials for a variety of high-temperature applications in chemical rocket engine throat inserts, combustion chambers and nozzles; aero-engine combustors, turbines and exhaust nozzles; hypersonic airframe hot structure and thermal protection systems; and a variety of industrial power generation radiant burner and heat exchanger tubes. Improved fiber coatings are critical for the success of these materials. Low dielectric ceramic composites, cuch as silicon nitride, combined with boron nitride-based fiber coatings are particularly enabling for critical military aircraft platforms requiring reduced radar cross-section, including low-observable airframe structures, engine exhaust nozzles, high-speed aircraft and missile radomes; low dielectric insulators Return