Low Cost 2D Laminated Ceramic Composites with Improved Interlaminar Strength Navy SBIR FY2005.2 Sol No.: Navy SBIR FY2005.2 Topic No.: N05-098 Topic Title: Low Cost 2D Laminated Ceramic Composites with Improved Interlaminar Strength Proposal No.: N052-098-0561 Firm: Hyper-Therm High-Temperature Composites, Inc. 18411 Gothard Street Unit B Huntington Beach, California 92648 Contact: Wayne Steffier Phone: (714) 375-4085 Web Site: www.htcomposites.com Abstract: The objective of this proposed effort is to demonstrate a ceramic composite material having improved interlaminar properties over typical fabric laminates using a commercially available textile process. Affordable fiber preforms using multiple plies of woven CG-Nicalon fabric will be dry-laminated and compacted in a perforated tooling fixture to the requisite fiber volume fraction. The preforms will undergo a thru-thickness needle punching process where a barbed needle will be used to pierce, draw and reorient a small fraction of the fiber in the out-of-plane, "z" direction while serving to mechanically interlock the layers of fabric within the laminate. Needle punching corresponds to the pattern of perforated holes in the preform tooling fixture. The density, or fraction of fiber reoriented in the "z" direction is therefore dependent on the pitch or spacing of these holes where the barbed needle passes. Several laminated preforms will be produced with increasing thru-thickness needling (increasing fractions of "z" fiber reinforcement) and then densified with silicon carbide produced by CVI. Coupon specimens from the various composite systems produced will be evaluated to determine their respective in-plane and interlaminar mechanical properties. These results will be compared to a "baseline" un-needled fabric laminated composite system to establish the overall viability of the proposed approach. Benefits: Hot structures fabricated from ceramic composite materials are an attractive design option for certain components of future aerospace vehicles and propulsion systems to reduce weight and increase survivability. Current fabric-laminated ceramic composite materials and components suffer from insufficient interlaminar strength and are thus vulnerable to delamination when subjected to high thru-thickness thermal gradients and/or normal loads. The ability to improve the interlaminar properties over current materials without having to resort to the use of costly, exotic multidirectional fiber preforms will better enable the utilization of these materials for certain thermal-structural applications critical to the US military and aerospace industrial complex. Fiber-reinforced ceramic-matrix composites are recognized 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; spacecraft re-entry heatshields; and a variety of industrial power generation radiant burner and heat exchanger tubes. Return