Rapid Deposition of Uniform Thickness Fiber Interfaces in Bulk Fabric for CMC Toughening
Navy SBIR FY2008.2

Sol No.: Navy SBIR FY2008.2
Topic No.: N08-148
Topic Title: Rapid Deposition of Uniform Thickness Fiber Interfaces in Bulk Fabric for CMC Toughening
Proposal No.: N082-148-0324
Firm: Physical Sciences Inc.
20 New England Business Center
Andover, Massachusetts 01810-1077
Contact: Michelle Schulberg
Phone: (978) 689-0003
Web Site: http://www.psicorp.com
Abstract: Physical Sciences Inc. will develop a BN/Si3N4 fiber interface coating that can be applied uniformly to fibers in a woven fabric and provide toughening in SiC fiber reinforced ceramic matrix composites (CMCs). Using traditional CVD precursors such as BCl3, NH3, and SiCl4, we will demonstrate a rapid, self-limiting, scalable vapor phase deposition process to create coatings of uniform thickness throughout the tows. Due to the improved uniformity of the fiber coating, the interface thickness can be reduced, increasing the flexibility of the fabric and ease of handling. We will fabricate a CMC plate from the coated fabric, measure the composite strength to verify toughening, and provide a conceptual design for a commercial-scale reactor to coat full bolts of fabric. During Phase II, we will optimize the thickness, composition, and morphology of the coating and will perform more extensive materials testing including stress oxidation. More uniform, thinner interfaces will improve the high temperature performance and reduce the manufacturing costs of CMCs for long-life applications in advanced propulsion components.
Benefits: Improved fiber interface coatings will enhance the long-term survival of SiCf/SiC CMCs at high temperatures in the presence of oxygen and water vapor. Use of CMC-based components will enable higher temperature operation of aircraft engines. The lighter weight of the CMC components will reduce fuel consumption and their higher temperature operation will reduce air cooling requirements, decrease NOx emissions, and improve overall engine efficiency. These factors will result in significantly reduced costs for aircraft engine operation.