PIP/MI Matrix SiC/SiC CMCs

Innovative materials and processing capabilities are needed for the fabrication of ceramic matrix composite (CMC) components for efficient engine systems. NASA has identified CMCs as the only materials that will meet the combination of increased safety, reduced cost, and reduced weight as operational temperatures climb to higher levels (per AeroMat 2000 Annual Conference, June 2000). The current UEET (Ultra Efficient Engine Technology) initiative at NASA is looking at components such as combustor liners and vanes in particular. In light of these needs, this Phase II SBIR proposal addresses lightweight, high temperature, and low cost CMCs for engine and propulsion applications, particularly in the temperature range of 1200-1400C. The work specifically addresses the optimization of a hybrid PIP/MI SiC fiber-reinforced SiC-matrix composite (SiC/SiC). Effort will focus on using SiNC- and SiC-yielding preceramic polymers and a combination of PIP and melt-infiltration processing routes that will reduce the cost and time for producing SiC/SiC composites compared to traditional CVI/MI processing. The intent of this work is to refine and optimize the PIP/MI process developed in Phase I, generate a database of thermal and mechanical properties, and demonstrate fabrication capability of subcomponents. The innovation of this work lies in the ability of PIP processing to protect the fibers and interphase coating in a uniform manner compared to the CVI process, resulting in faster and less expensive processing as well as less variability in material properties.