Boron Nitride-Based Fiber Coatings for 3D Fiber-Reinforced Ceramic Composites

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.