Interface Chemical Modification for Property Control of Oxide Reinforced Ceramic Matrix Composites

Abstract : The Air Force requirements for high temperature structural materials include applications in aircraft afterburner and in propulsion systems. Ceramic matrix composites are candidate materials systems for several types of these applications. In the effort to develop composites for high temperature structural applications attention has turned towards oxide-oxide systems. The objective of this project is to systematically investigate the segregation behavior and high temperature stability of complex oxides. The project has an experimental and a theoretical component. The approach combines Auger electron spectroscopy (AES), Rutherford backscattering spectrometry (RBS) and scanning probe microscopies (STM, AFM), along with conventional transmission and scanning electron microscopies (TEM,SEM) to characterize surface and interface composition. The theoretical approach emphasizes a coherent model of segregation that connects statistical mechanics and first principles calculations. This work is in collaboration with the R. Kerans and the Ceramics Group at Wright Patterson Air Force Base.