Theses and Dissertations Collection

Hafnium Carbide and diboride are ceramics with ultra-high melting temperatures representing the upper end of refractory materials. Current standard syntheses form powders in an energy intensive carbo- (boro-) thermal reduction or coatings via vapor deposition, a time consuming process requiring high vacuum conditions. Research is being done towards an alternative by thermally decomposing preceramic polymers, such as polycarbynes and "polyborynes".

High atomic weight polymer networks enable the conversion from amorphous polymer to ceramic. For synthesis of polycarbynes, studies on Wurtz coupling of sp3 coordinated bromoform initiated with alkali metals have been published, but these reactions are extremely exothermic and potentially violent.

In an effort to reduce the hazards, reaction set up was performed in a glovebox and the reaction rate was controlled with ultrasonic vibrations. Work towards the "polyboryne" precursor will follow a similar reaction pathway to polycarbyne synthesis.