Part 1. Application of CVD-yttria for the protection of SCS-6 silicon carbide fibers in a reactively sintered nickel aluminide matrix composite. Part 2. CVC pyrolysis studies of various 1,3-substituted 1,3-disilacyclobutanes and application as single-source CVD precursors to silicon carbide

A CVD process was developed for coating Textron-Avco SCS-6 SiC fiber with yttria, examining various potential Y2O3 CVD precursors. The coated fibers were incorporated into a nickel aluminide (Ni3Al) matrix by reactive sintering, with yttria affording protection from the known SiC + 2Ni → Ni2Si + C degradation process. The SiC/Ni3Al composites, before and after annealing at 1000 degree C for up to 100 h, were studied by using SEM and EMPA to determine the extent of reaction. Exception for certain portions of the fibers that were inadequately coated with yttria, complete protection of the fibers was indicated. Low-pressure chemical vapor deposition (LPCVD) of silicon carbide on Si(100) was investigated between 700 and 1100 degree C at ca. 1.0 torr total pressure using a flow or argon as a carrier gas in a cold-wall total pressure using a flow of argon as a carrier gas in a cold-wall LPCVD system. The gaseous byproducts were determined for each compound, surface and cross sectional morphology was determined and film composition and crystallinity were monitored as a function of deposition temperature. These silicon carbide coatings exhibited preferred crystal growth in the SiC(111) which was quantified for two such coatings via a texture study