Ceramic Matrix Composite (CMC) Structures for Vanes and Exhaust Nozzle Components

The objective of this proposal is to demonstrate the feasibility of the application of a patented microwave scanning device as an NDE technique to be used in streamlining and optimizing the Ceramic Matrix Composite (CMC) manufacturing process. The scanning process (U.S. Patent numbers 6,359,446 and 6,653,847) utilizes microwaves as an interrogating beam to penetrate a dielectric material. This method has been used successfully in preliminary NDE studies of CMC components for jet engine vane and exhaust nozzles. This method is capable of providing a quick and accurate measurement of CMC porosity, which represents a significant time savings over the current Archimedes principle porosity measurement method. This investigation will be supported by a CMC manufacturing company (ATK) and a jet engine manufacturer (Pratt & Whitney). Currently, the parts are submerged in a liquid and the density is calculated using the weight and the change in water volume. The porosity is then determined as the ratio of the non-porous material density versus the measured density. This process is repeated multiple times during the manufacturing process, which results in multiple drying cycles for the part. Additionally, the method only measures “open” porosity and not porosity which is closed off from the surface.