Environmentally-Robust Matrices for SiC Composites

Ceramic Matrix Composites (CMCs) are emerging as mission-critical materials for a broad range of defense applications and among them, their utility for next-generation aero-turbine components are currently being pursued. SiC-based CMCs are leading candidates for this application due to their high strength, low density, and superior toughness at elevated temperatures. In this Phase I project, a new matrix material is being proposed based on the concerns for the environmental durability of SiC under turbine service conditions. At elevated temperatures, degradation of SiC CMCs due to presence of oxidation, moisture, salt, and CMAS is well known. While barrier coatings deposited on exterior surfaces can mitigate the problem to a certain extent, it is becoming apparent that more robust ceramic matrices need to be developed using low-cost approaches. In this regard, recent advances with preceramic polymer-derived matrices are noteworthy. This Phase I project addresses a unique and innovative matrix material using CMC-compatible processing technique to enhance the durability of SiC CMCs in such harsh environments. Fabrication of CMC samples, exposure tests, and mechanical testing comprise the major tasks in this project. Partnership with a prime defense contractor and manufacturer of CMCs is established for this investigation to provide technical guidance.