ilicon-doped boron carbide

Researcher: Dr Vineet Bhakhri

Supervisor: Dr Finn Giuliani

Funding: MOD

A variety of synthesis routes were researched and tested in this project in an attempt to synthesise silicon-doped boron carbide nanostructures. This is a potentially interesting material as it has been theoretically predicted that the addition of Si would suppress a potentially weak polytype of boron carbide resulting in significant increase in performance particularly for armour applications.

The conducted set of experiments has resulted in partial success. The most successful synthesis routes produced some boron carbide nanowires in fractions of less than 1%, growing via a vapour-liquid-solid or solid-liquid-solid mechanism but low yield of nanostructures remained a concern. In order to increase the yield, the vapour pressure was increased by increasing both the temperature of the furnace and the volume of reactants relative to the volume of the furnace. The resulting produce was made up of platelet with composition including stable poly-types B11C3/B13C2. This combines with post growth plasma processing in collaboration with University of Birmingham has increased the yield to above 50% and subsequent in situ high pressure testing at I15 (diamond light source) in collaboration with the Edinburgh University is consistent with the suppression of the weak polytype.