Nanostructured titanium disilicide powders: Preparation by self-propagating high-temperature synthesis and mechanochemical processes and physicochemical properties

Resumo

Nanostructured titanium disilicide (TiSi₂) powders with semiconducting properties have been prepared via cold fusion of silicon and titanium nanopowders and mechanochemical activation of TiSi₂ powders prepared by self-propagating high-temperature synthesis. The semiconducting properties of TiSi₂ have been shown to be determined by the nanocrystallite size. Basic to the formation of TiSi₂ as a semiconductor material is a change in its band structure upon the conversion of the conductor to a semiconductor. The transformation takes place when the crystallite size decreases from microns to the nanometer range (≤70 nm). Such crystallites are nanoclusters with distorted order in the arrangement of the silicon and titanium atoms.