Novel Three-Dimensional Silicon Carbide Nano-Structures
Hart, Amelia HS Church
Ajayan, Pulickel M; Vajtai, Robert
Doctor of Philosophy
Silicon carbide nanotubes have been found to have the same excellent mechanical properties in extreme thermal and oxidative environments as bulk silicon carbide, but with the resiliency similar to carbon nanotubes due to quantum size effects. The simplest, most cost efficient method to synthesize silicon carbide nanotubes is conversion from carbon nanotubes. By investigating the conversion mechanisms of carbon nanotubes (CNTs) to silicon carbide nanotubes (SiCNTs), studying their resulting properties, and applying them in different ways, two composites can be created for use in applications that require optimal mechanical properties in high heat and oxidation. The first structure involves covering continuous silicon carbide fiber with protruding silicon carbide nanotubes, dubbed “fuzzy” fiber, which is created to be woven, layered, and put inside a ceramic matrix for extremely high temperature heat engines encountered in aerospace applications which come into contact with high heat and oxidation. The second structure is a silicon carbide nanotube/nanowire sphere that can be used for its excellent compressive strength and resiliency as well as its resistance to high heat and oxidation. By converting carbon nanotubes to silicon carbide nanotubes/nanowires, structures that are more easy and cost effective to obtain, can be synthesized to maintain excellent mechanical properties in high temperature and oxidative environments.
Silicon Carbide; Silicon Carbide Nanotubes; Silicon Carbide Nanowires; Carbon Nanotubes